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e30 M3 minor rust repair.

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    (continued from previous page)
    With all that done, we pop the crownwheel and cups back off again,
    and start fitting up the pinion. First up drop in the outer pinion

    followed by the seal.....

    and then the inner pinion bearing is pressed on to the pinion shaft
    and then the colapsable spacer(arrowed) is dropped on as well.....

    this lot is then pressed into the casing and up through the outer
    bearing. The pinion flange is popped back on and special tool

    and the pinion nut is retightened.....

    Theres no torque for this nut as again your using it to "preload" or
    squeeze the two bearings below it just the right amount.
    When retightening it you can feel the nut first tighten a little bit as
    the outer bearing gets squashed up against the collapseable spacer,
    but the pinion still is able to slap up and down in the direction below....

    What has happened here is the both bearings have not been squeezed
    close enough together yet and they can lift up and down off their races
    because that collapsible spacer is keeping them apart.
    So, the nut is tightened down more, slowley, crushing the collapsible
    spacer till theres no up and down play and the bearings are sitting snugly
    in their seats and then ever so slightly tightened again in little steps till the
    right preload is got on the bearings. This extra bit of squash (preload)
    on the bearings is done because when you nail the accelerator pedal
    if the bearings were just fitted loosely they'd start to lift out of their
    races and the pinion would start it's break for glory out through the
    diff casing. Instead of leaving two nice big black tyre marks you end
    up leaving one nice big trail of diff oil and gears.
    Again there is a special tool for measuring the correct preload and
    the figures for it are in the manual.

    With everything tightened up correctly and a quick splash of holy water,
    the lock washer is bent in to place....

    casing is flipped over and crownwheel unit and cups refitted....

    and halfshaft flanges refitted....

    And then finally on to the most important check of the lot,
    tooth contact. Some engineers blue....

    spread evenly on 3 crownwheel teeth.....

    and then rotate the diff gears by turning the front pinion flange while
    putting a bit of loading on it by holding one of the output flanges loosely....

    and what your left with should be a marking on the crownwheel teeth
    of where the pinion teeth are contacting it. What your looking for is a
    nice fat contact patch in the middle of the tooth, something like below....

    If the contact patch is too high up towards the tip off the tooth you'll need
    to move the pinion gear closer to the crownwheel by putting a fatter
    shim under the inner pinion bearing.
    And if it's too low to the base of the tooth you'll need to fit a thinner shim
    to move the pinion gear back away from the crownwheel.
    If the contact patch is too far towards the inside of the crownwheel tooth
    then you've got to change the crownwheel bearing cup shims to move
    the crownwheel away from the pinion gear.
    And likewise if the contact patch is towards the outside of the tooth
    change the cup shims to move the crownwheel towards the pinion
    Again if none of the main components have changed during the overhaul
    then the contact patch should be pretty close to right, but you still
    gotta check. If you get the tooth contact patch badly wrong, then don't
    worry to much about it, you'll be getting a chance to rebuild it all again
    after a few miles, when it sh*ts itself.

    After all that mind numbing crap is done, a bit of gasket sealer....

    under the gasket and a little smear above....

    bolt the rear cover back on....

    pop the speedo sender back in with a fresh o ring....

    bungs back in and fill with oil and thats it....

    and all that waffle was for a case with 2 gears and 4 bearings,
    I'm buying a new keyboard for whats coming next.....

    till next time....


      Wow thanks for posting step by step pics. This thread deserves its on subforum.
      Last edited by ///M42 sport; 11-19-2009, 04:05 PM.
      Renting my rear wheel bearing tool kit. SIR

      Your signature picture has been removed since it contained the Photobucket "upgrade your account" image.


        Originally posted by ///M42 sport View Post
        Wow thanks for posting step by step pics. This thread deserves its on subforum.
        You said it. Totally over the top workmanship and photo-documentation. Makes me embarrassed about how I take care of my E30. Also a classic thread title, "minor rust repair."
        "If the sky were to fall tomorrow, the tall would die first."

        -Dr. Paul Forrester

        Do I LOOK like I need a psychological evaluation???


          Damn good blow-by-blow writeup there.

          By the way, that diff bushing looks like the reinforced M version. Do you have the part# or which model/year it came from?


            Originally posted by evilnickwong View Post
            Damn good blow-by-blow writeup there.

            By the way, that diff bushing looks like the reinforced M version. Do you have the part# or which model/year it came from?
            Sorry for the delay replying I bought the bush here.....


              Wow. I was getting ready to rebuild my diff this winter, but after seeing all this and the amount of work it takes I may just send it to a shop. that PDF you linked takes like 50 pages to explain it and uses dozens of special tools. Not to mention I'm rebuilding my limited slip unit at the same time since mine seems to no longer be working.
              Last edited by CorvallisBMW; 11-26-2009, 07:48 PM.


                Evenin all,
                Bit of a gap since the last update, was so busy working on the car
                I couldn't get time to write up all the work. Managed to get a lot
                done since the last update.

                And when you run that through the "Babelfish Bullsh*t Translator" it comes out
                Ages since the last update cause the shed feels like the inside of a freezer
                at this time of year and everything you pick up brings frostbite a step closer.
                The heater heats itself and nothing else and the camera took on a life of its own
                and decided to mix up all the photos for the crack.

                So heres what actually got done.
                The driveshaft....

                despite looking their age both joints on the shaft still rotate in all directions
                without any sticking or tightness, so a clean up and they're good to go.....

                what is getting changed is the centre bearing. Before splitting the shaft
                a quick check for the original marks to help align it correctly when going
                back together. If they're gone, two small dabs of tipex will do.....

                collar screwed back off the shaft and splines slid apart.....

                a slice around the rubber allows the outer piece of carrier bearing
                to be cut away (along with tops of fingers).....

                pop the circlip and the large washer behind it off....

                and then simply pull the bearing off the shaft with the pullers....

                which is how it goes in the fantasy world of "workshop manual land".
                However in the real world no amount of pulling, beating or swearing
                would remove the bearing. So the special bearing removing tool had
                to be used, also known as an angle grinder.....

                shaft gets a quick lick of sandpaper to clean up where the new
                bearing is going to sit....

                the new carrier bearing has the bearing recessed on one side like so......

                and flush on the other side like so.....

                the bearing in the centre is heated up using the heat gun....

                which allows it to slide up on to the shaft easily, with the recessed
                side facing in and the flush side facing out like so.....

                then the washer and circlip go back on and if you've fitted the
                bearing the wrong way around you now realise the cirlip won't
                reach in to fit in it's groove anymore, which will mean the whole thing has
                to come off again to be flipped around, which is nice......

                then the threaded cup is slid back up on to the splines, some copper
                grease on the splines and then the other half of the shaft is slid back
                on with the white marks aligned....

                The threaded cup isn't tightened up to lock the shaft length till it's
                all refitted back on the car and extended to the correct length....

                The last thing to do then was rebolt the rubber "guibo"
                or donut onto the gearbox end of the shaft. Mine was in
                good nick as i'd only replaced it a while back. Unfortunately
                shortly after replacing it I read about the E34 M5 one
                (p/n 26 11 2 226 527) being a straight forward replacement,
                only its alot thicker and as such most probably longer lasting,
                (f*ck it anyway)......


                  With the driveshaft out of the way, there was no avoiding it any longer,
                  next up was going to be the big aluminium box full of gears.
                  First thing to note is, the following waffle is all about the Getrag 265/5
                  dogleg gearbox. The bit thats worth noting about that, is, the 265/5
                  gearbox is the dog leg gearbox, meaning that 1st is all
                  the way over to the left and down (under reverse).
                  The Getrag 265/6 which was also fitted to M3's (mostly
                  American versions I think) is the non dog leg 5 speed overdrive gearbox.
                  It pays to make a mental note of the difference between a 265/5 and
                  a 265/6 cause when your looking up parts on real.oem or looking up
                  the manual for torques or proceedures theres a difference between
                  the two internally. And its frustrating ordering in parts for your
                  box only to find upon collection that the bits you've ordered are
                  for the wrong one and are non refundable. (And despite trying,
                  no amount of hammering will make them fit)
                  On to the actual disassembly of the box. This is
                  a very complicated proceedure, and I'm now going to attempt to
                  explain the highly skilled, meticulous, disassembly of my gearbox.
                  Measure in exactly 253 mm from the rear output flange and
                  up 176mm from the bottom of the casing on the left hand side and
                  mark this spot with a large red x.....

                  Then hit this spot an unmercyfull wallop with special tool part
                  no. 959sledgehammer.....

                  and ta-daaaa......

                  (click on this link for full size image:

                  For anyone who's not comfortable using the sledge hammer method of disassembly,

                  the the full strip down procedure is given here in the Bmw workshop manual....[/color]


                  [color=white]click the link, click on the "contents" box, click on "23 manual transmission"
                  and then make sure you click on the right gearbox 265/5 or 265/6.
                  With the gearbox assunder it can help a little to know how all this crap in
                  here is supposed to work. If for no other resason just so you can easily
                  identify what part of the rebuild has gone t*ts up.

                  WARNING: You will most likely know less about the workings
                  of a gearbox after reading my explanation than before reading it.
                  Inside the gearbox casing theres 3 main shafts.....

                  Theres one or two cogs missing from the above picture but its enough to
                  get the idea. Pictured are the 3 shafts, the input, output and layshaft. The first
                  thing thats makes fuck all sense, at first, is how is the top shaft in the picture is
                  in fact two shafts (input shaft & output shaft)?
                  The input shaft as seen below is short and only has one gear
                  and one bearing on it, and in the end of the input shaft is
                  a hole with a small roller bearing in it which allows the other
                  shaft, the output shaft, to sit into it and be supported......

                  new bearing in the hole, old one out on the bench....

                  The whole idea behind this setup is that the two shafts can move at
                  different speeds to each other. The input shaft at the front of the box
                  is connected through your clutch to the engine flywheel. So, with
                  the clutch let out this shaft is always spinning at engine speed. The whole aim
                  of the game is to pass this drive through a series of gears to reduce the revs
                  coming out the back of the box. 1st gear reducing it the most, working
                  right up to 5th gear which in this box is 1:1 ie one turn in = one turn out.
                  And heres the selection of gears it uses to do this......
                  (1st and reverse are missing from right of pic)

                  With the input shaft spinning the one gear thats solidly connected
                  to this (5th gear) is also spinning....

                  and because 5th gear on the input shaft is also connected to
                  5th gear on the layshaft (underneath it) then the whole layshaft
                  is also spinning too. And because basically the layshaft is one
                  big solid lump of metal, then all the other gears it's in contact with
                  are spinning too.
                  So, gearbox in neutral, engine turning over, all thats marked
                  red is spinning at engine speed....

                  So how the fu*k is the output shaft coming out the back of the box
                  not spinning if all the gears on it are spinning?......

                  The answer is all the gears on the output shaft (top shaft), while sitting on it, are
                  not actually connected to it. Between the centre of the gears and
                  and the shaft are little roller bearings, so no matter how fast you
                  turn the gears you wont turn the shaft.....

                  So to get the output shaft to turn you have to "lock" one of these
                  gears to the shaft and to do this you use the syncro hubs.....

                  The syncro hubs sit in between the gears and have two main pieces.
                  The centre of the syncro hub is connected solidly to the output
                  shaft by splines (red bit in pic below) and the outside part (blue bit)
                  is also splined onto the red bit, the only difference being the
                  blue piece can slide over and back on the red piece.....

                  The reason it can slide over and back is so it can lock on to these little
                  teeth on the side's of the main gears (red piece below) while also staying
                  connected to the centre of the syncro hub.........

                  So when the blue piece of the syncro hub slides over to grab these
                  red teeth in the pic below it's also still connected to the centre piece
                  of the syncro hub, and bingo, you've just locked one of the gears
                  to the output shaft. Now the output shaft is being driven......

                  In the pic below the red syncro hub is slid to the
                  left and the gear to the left of it (3rd gear) is "engaged" and locked to the
                  output shaft, hence the output shaft (To Differential) is now
                  been driven by the engine.....

                  The other bit in here thats important is the syncro ring.....

                  It sits in between the gear and the syncrohub and it has the shittiest job
                  of the lot. When the syncro hub moves over to grab them little teeth
                  on the side of the gear and lock it on to the shaft it runs into a little
                  problem. The hub and the gear are rotating at different speeds. So
                  if one tries to mesh with the other like this then theres going to be
                  a horrible sound in the gearbox and a whole lot of new little bits
                  stuck to that drain bung magnet. What needs to happen is the two
                  need to be rotating at the same speed so they can lock together.
                  This is where the syncro ring comes in. The inside of the syncro ring
                  is cone shaped.....

                  and the bit of the gear it slides on to is also cone shaped.....

                  so as the syncro hub sleeve moves across it grabs the brass syncro
                  ring first and then squeezes this up against the gear to get it rotating at
                  the same speed and then as they synchronize it can then slide fully across
                  and lock onto the gear......

                  And then at last, the final bit, for anyone left that hasn't got bored and
                  logged out to go look for porn sites. How does moving one simple
                  gear lever from up in the drivers seat move all these syncro hubs
                  down in the gearbox?
                  The box has 6 gears, 1st 2nd 3rd 4th 5th and reverse that can be selected.
                  Each syncro hub can slide forward or back to select the gear in front
                  of it or behind it, so thats 3 syncro hubs that need to moved.
                  A brass "selector fork" sits on to each one of these syncro hubs....


                    and these 3 selector forks are solidly connected to 3 rods....
                    (only 2 forks in picture)

                    Theres also another rod in there too, its the "selector rod" and its
                    the only one thats connected to your gearlever. When you move your
                    gearlever right it rotates right, move your gearlever left it rotates left.....

                    attached to this "selector rod" (the funky green one) is a finger (also
                    funky green). And as mentioned when you move the gearlever left
                    and right when in neutral the green rod rotates left and right moving
                    this green finger up and down between the 3 selector fork rods
                    (funky purple, blue and yellow).........

                    move the gearlever all the way to the right, the selector rod
                    rotates all the way to the right and the finger moves all the way up
                    to engauge with a cut out in the purple rod. Now when you move
                    the gear lever back or forward in to 4th or 5th gear position the
                    green finger moves the purple rod backwards or forwards, which
                    in turn moves the purple fork which moves the syncro hub forward
                    to engage 5th gear or backwards to engauge 4th.....

                    Leave the gear lever in the middle position and move it backwards
                    or forwards between 2nd and 3rd gear position and the green finger
                    hooks up with the blue shaft and fork moving the 2nd/3rd syncro hub
                    locking in either 2nd or 3rd gear.....

                    and finally move the lever all the way to the left over for reverse
                    and first, the green finger gets rotated all the way down to hook up
                    with the yellow shaft and either select 1st or reverse down the back
                    of the box......

                    And thats roughly how it all works,

                    I think,


                    The main reason for pulling the box asunder was I wanted to replace
                    the bearings in there. A couple of months before pulling the car off
                    the road a nasty clicking sound came into the front end of the gearbox,
                    so we pulled the box and stripped off the front casing to try and find
                    the culprit before the clicking progressed to a knocking and finally
                    the big "boom". The front input shaft bearing looked ok, a little bit gritty
                    when spun but not the cause of the noise....

                    and then we went on to the one under it, the front layshaft bearing.
                    We had a sneaky feeling this could have been the cause of the noise.
                    Call it a sixth sense if you will but there was something bugging us
                    about this bearing. Here's the two of them side by side, it takes a
                    sharp eye to spot the difference, but if you look close enough you
                    should be able to see the tiny defect.....

                    Yeah, the bearing cage had completely shit itself, allowing the balls
                    to move around as they pleased, which had resulted in the clicking
                    sound. The cage that holds the balls spaced out is made out of a hard
                    plastic type stuff (*might not be correct technical term). And the reason
                    it had broken up was the inner race of the bearing had started to pit,
                    and got worse over time, which meant the little balls were bouncing
                    over the pothole created......

                    Eventually it got to hard for the plastic cage to hold on to the balls
                    as they bounced and it broke up. Next up had the box been kept
                    driven would probably have been one of the balls getting jammed
                    or popping out of the bearing, either of which would probably have
                    resulted in a nice little explosion of bits inside the box. Thankfully
                    due to that clicking sound we got a little warning that the end was
                    coming. At the time we only replaced the front end bearings because
                    the car is my everyday car and I needed it back on the road as soon
                    as possible. So now it's all coming asunder and all the 5 main bearing
                    in the box are getting changed.....

                    Number 4 and 5 in the pic above are on either ends of the layshaft (bottom shaft)
                    and are just normal bearings available aftermarket. The front layshaft
                    bearing (on left in pic) 25x62x17mm was replaced with a Timken
                    bearing p/n 6305/C3. The rear one (on right) 72x30x19mm was
                    replaced with a SKF bearing p/n 6306/C3....

                    Number 3, the rear bearing on the output shaft is identical to
                    the number 5 the layshaft rear bearing, and again was replaced with
                    a SKF bearing p/n 6306/C3.....

                    So that just left us with number 1 and 2 to source. I could only get
                    these from the main dealer as they're a bit odd ball bearings.
                    The first one (number 1 bmw p/n 23121204580 ) the input shaft bearing
                    is special because it has a groove cut into the outside race to take a circlip
                    as seen below......

                    This must be made from rare minerals as thats the only reason I can
                    see why it cost 80 something euro! But if that one was made from
                    rare minerals then they must have to travel all the way to the moon
                    to get the stuff to make bearing number 2 (bmw p/n 23231205191).
                    This is a 2 piece needle roller bearing and it weighs in at 208 euro.
                    That hurt.....

                    With all the main bearings done it was time to move on to the smaller
                    ones. The red arrowed one below was changed because it has one of them
                    hard plastic races holding it together and these get brittle over time....

                    bmw p/n 23221207784.......

                    all the blue arrowed ones are the little double row needle roller
                    bearings that fit inside the gears. These were available after market
                    but had a 4 week order in time so I just got them from the main
                    dealer instead (bmw p/n 23221228279)......

                    Only 2 of them little needle roller bearings ride on the shaft, the rest of
                    them ride on their own little separate inner race's pictured below.
                    None of these needed replacing as there was no marks on them
                    and they showed no signs of wear.....

                    The other thing that I wanted to pay special attention to while in here
                    was the syncro rings. 1st gear had a habit of being awkward to select
                    in this box in stop go traffic, especially when warm. So all the syncro's
                    got checked while assunder.....

                    to check them the syncro ring is placed on top of it's gear, lightly pressed
                    down and the gap (arrowed below) measured with feeler blades.....

                    for a new syncro ring sitting on a gear the gap is 1.0 to 1.3mm
                    if the gap on the old one is below 0.8mm she kaput.
                    The only difference is reverse gear, 0.5-0.6 new less than 0.4mm replace.
                    Given I couldn't fit a fly's pubic hair bewteen my 1st gear syncro
                    ring and the gear I could safely say it was fu*ked...

                    One of the other things that got checked was the shift forks. These
                    sit into the groove on the syncro hubs and push them backwards and
                    forwards. As the syncro hubs are allways spinning and the fork are
                    allways held still, the side faces of the forks can tend to wear, giving
                    a slopply gear change (you have to move the gear lever move before
                    a worn fork actually starts to move the syncro hub)......

                    minimum fork thickness is 4.8mm, thankfully mine were all good to go.....


                      With everything cleaned, checked and replaced if worn, it was time to
                      try and figure out how it all went back together.
                      Starting with the rear casing......

                      and this little collection of bits whose job it is to spring load the gear
                      lever when your moving it from side to side in neutral....

                      smaller of the two springs dropped in like so.....

                      flat washer and circlip on top, to stop it wandering....

                      and then this little tube whose job it is to grab the selector rod....

                      as you can see the tube has a specially cut internal section which allows
                      the selector rod to side back and forth inside it undisturbed, but when
                      the selector rod is rotated left or right (when you move the gear lever
                      left or right) it rotates the whole tube left or right......

                      the selector rod is kept free during all this movement thanks to 4
                      little rollers stuck on the shaft (one hidden underneath)....

                      the tube sits into the casing like so.....

                      making sure the leg attached to the tube is the right side of that first
                      spring that was fitted.....

                      the second bigger spring goes on next, the legs of which sit like below......

                      followed by a washer and circlip.....

                      next up is the method of stopping the gear lever from being pushed
                      to far to the left or right. The little tube just fitted has an elongated
                      notch cut into it like so......

                      and when in place this notch lines up inside with this hole on the casing.....

                      into which is screwed this little locater bolt....

                      before screwing it in, its given a dab of loctite to lock it in place but
                      also to seal it so gearbox oil can't weep out.....

                      when it's in theres the head of the bolt and the casing has been drilled
                      for lockwire.....

                      so some lockwire is fitted....

                      when all that crap is fitted this next little selection of stuff is hammered
                      in, in this order....

                      into this hole....

                      this little plunger gives you that extra bit of spring force to overcome
                      when your pushing the gearlever all the way over for reverse. A little
                      bit of gasket sealer on the sides of the black plug below on fitment
                      helps keep it oil tight.....

                      After that it's onto the centre casing and the fitment of the worlds most
                      expensive gearbox bearing. Only fitting the outside piece of this at the
                      moment, the inner ring will be used later....

                      the aluminium casing around the bearing hole in the centre of the casing
                      is given a nice heating with the heat gun, to ever so slightly expand it,
                      which allows the colder bearing to slide easily into place. The bearing
                      only fits in from one side as theres a ridge to stop it sliding through....

                      then the two little countersunk allen key head bolts are fitted through
                      the casing and screwed into the 2 little retainer tabs which stops the bearing
                      falling out the other side. Bit of loctite on these two bolts does no harm....

                      After that it's on to the replacing the 2 layshaft bearings......

                      the front old one is pulled off....


                        new bearing is heated up with the heat gun and popped on....

                        the bearing the other end is only a small bit more involved. The bearing
                        is behind the last gear on the shaft, so the bolt and fat washer that holds
                        this gear on is first removed, and then the gear is pulled off its splines
                        on the shaft.....

                        with the gear out of the way, the old bearing is pulled off and new one
                        heated and slid on......

                        and then it's time for the first bit of shimming.
                        When the gear is pushed back on the shaft on top of the new bearing,
                        its up to the fat washer and bolt to hold them all secure and tight.
                        If the gear was pushed back on the shaft and wasn't level
                        with the top of the shaft, then when the fat washer and bolt were tightened
                        down the gear and bearing would still be free to wobble around a
                        little underneath it.
                        So, with a depth gauge, the length of exposed shaft on top of the bearing
                        (marked X below) is measured....

                        "X" was measured at 34.8mm.
                        Then the length of the gear is measured (Y)....

                        and as you can see it was 34.7mm
                        So a 0.1mm shim is needed to bring the gear flush with the end of the

                        shim fitted, gear heated up and slipped on, fat washer refitted and
                        bolt loctited and tightened back in place. Layshaft finished.....

                        After that it's on to short the input shaft, replacing the front bearing
                        first (making sure the recess in the outer race for the circlip is facing
                        away from the gears as pictured).....

                        and then the little bearing in the end of the shaft.
                        (new one fitted, old on on bench).....

                        After that it's on to the output shaft which holds the majority of
                        removable pieces.There's a collar at one end of the shaft which
                        means the shaft is built up in two steps as arrowed....

                        first up the long side is built up. The shaft is placed into special tool
                        p/n 959axlestand to hold it secure......

                        first up one of those little double row needle bearings
                        (like the one shown below) is slid on.....

                        then 3rd gear and a syncro ring is slid on....

                        followed by a syncro hub. The syncro hub is a tight fit on the shafts
                        splines so it's heated with the heat gun first to expand it and allow it
                        to push on by hand (soon to be burnt hand).....

                        after that its another syncro ring (they're all identical to each other),
                        followed by 2nd gear....

                        another of those needle bearing slides inside the gear
                        (like the one pictured below).....

                        this bearing however isn't a snug fit on the shaft, instead it runs on
                        a removable collar like below, so the collar is slid down in between the
                        bearing and shaft.....

                        After that, next on is the centre piece of the worlds most expensive
                        gearbox bearing (yeah that price really got to me)....

                        And thats as far as can be built up this end of the shaft at the
                        moment, so, the shaft is rotated in the stand and we start building up
                        the other end.....

                        first on this end is another of those double row bearings....

                        followed by 4th gear and it's syncro ring.....

                        and then a syncro hub (again heated in the centre to slide on easy)....

                        and with the syncro hub in place, last to go on this end of the shaft is
                        a fat spacer and a circlip to hold everything in place. Again everything
                        has to be held on tightly this end of the shaft, there can be no play for the gears
                        to move around.
                        So, with that in mind, that spacer under the circlip comes in a range
                        of different sizes, going up in small increments. Pop the circlip on
                        without the washer under it, measure the gap below it and then use the
                        largest size spacer that will fit to keep everything packed tight
                        (use a new circlip going back, they only cost buttons and if the
                        old one fails it'll cause the box to go "boom") .....

                        and with that done the input and output shafts are fitted together
                        (one just slides in to the end of the other)....

                        and then the whole lot is popped back up in to the stand again
                        for a bit of measuring.....

                        The measurement we're after this time is is marked "A"
                        in the pic below. And it's the distance from the top of
                        the expensive bearing inner race up to the next "ledge"
                        on the shaft at the top of those splines.....

                        same idea again as the layshaft shimming. The stuff thats going
                        on the shaft here needs to be held tight by the stuff that comes
                        on top of it. Only problem is the stuff coming on top of it will only fit
                        down as far as this "ledge" in the shaft. So we've got to make
                        sure this stuff fits on level with the top of the ledge.
                        And this is done by measuring the piece of shaft with
                        a depth gauge ( "A" = 52.5mm)......


                          And then measuring the stuff thats sliding on here.
                          First of which is a syncro hub. Theres 3 of these in total in the box
                          and while the other 2 are identical to each other, the one that fits here
                          has 2 small important differences. The centre's of both the other
                          syncro hubs are smooth on both sides, like the bit marked red below.....

                          The one that fits here however has a small step in it on one side,
                          arrowed below.....

                          The second difference from the other two hubs is this little groove on
                          one side of the outside ring, which doesn't concern us right now....

                          right, back to what we need to measure, one of the little needle roller
                          bearing collars that fits inside each gear is held up against the smooth
                          side of the syncro hub like so.....

                          and using a micrometer we're measuring to the inside ledge of
                          the step on this side of the syncro hub, like so......

                          which when measured came to 53.3mm ("B"). So the height of the
                          stuff we're fitting to the shaft is 53.3mm and the length of shaft we
                          need to fill is 53.5mm to bring them flush with the end of the splines.
                          So taking "B" from "A" (53.5mm - 53.3mm) gives us the gap we need
                          to fill with a shim = 0.2mm. That shim ain't been fitted yet though, we
                          have a bit of assembly to do first.

                          The input/output shafts and the layshaft are placed together like so.....

                          the middle casing is popped up into the vise and the metal around the
                          centre holes where the bearings fit into are heated up with the heat gun
                          to expand them.....

                          and then while it's nice and hot the shafts are offered up and
                          slid through like so.....

                          and now that the shafts are fitted to the casing we can pop on that
                          little 0.2mm shim we measured....

                          followed by the bearing collar (which was heated cause it's a tight fit
                          on the shaft).....

                          and then the bearing.....

                          and then 1st gear is slid on meshing with 1st gear on the layshaft
                          beside it.....

                          next up was that shiny new syncro ring.....

                          and finally that odd ball syncro hub, making sure that the recess cut
                          out of the outer ring is facing in towards the casing....

                          the only snag is, when fitting this last syncro hub you've got to fit it's
                          shift fork and rod at the same time.....

                          like so......

                          because if you don't, you'll never get the fork on afterwards, and even
                          if you did manage it, theres no access to knock in the roll pin that
                          secures the fork to the rod......

                          There's two other things thats probably worth noting at this stage.
                          The first is, theres a few little notches machined out of the end of the
                          shift fork rod, circled below.....

                          theres two ways you can roll pin that shift fork onto the rod,
                          1) like above with the notches facing downward which is correct, or,
                          2) the rod rotated 180degrees from above pic,which leaves the notches
                          facing upwards, which you only find out much later is the wrong way around
                          and means dissembling the lot to switch it around again.
                          (the urge to take out a hammer and chisel and beat some new notches
                          into it out of frustration will take a lot of effort to subdue at this point).

                          The other point worth noting is although the 3 shift forks will only go
                          together in the box the right way (they won't physically fit any other
                          way) it still helps a lot, if upon disassembly, you scribe onto the side
                          of each fork, an arrow showing which way it faces (towards front of box)
                          and which syncro hub it came off (ie. 5th/4th, 3rd/2nd or 1st/rev).
                          It just saves a lot of head scratching while you try to figure it out
                          upon reassembly. Which when all assembled ends up looking like

                          once happy that all notches and forks look like they are where they
                          should be, then it's time to hammer in the remaining roll pins....

                          With all that crap done it's back to building up the end of the
                          output shaft again. Remember that last odd ball syncro hub that
                          was fitted with the little ridge in the centre?....

                          well now we get to see why it was important the ridge faced out
                          this way. These two little thrust type washers......

                          pop into that ridge.....

                          which is then followed by the last syncro ring and reverse gear.....

                          and the little bearing for inside the gear.....

                          and finally heat up the bearing cone and slip it in between the bearing
                          and the shaft.....

                          next to go on is a 0.5mm shim, no measuring or calculating for this one,
                          every box just gets a 0.5mm shim here.....


                            One of the final things to go on the shaft is the last of the bigger
                            main bearings. But before it can go on we needed to do a bit of
                            measuring with it first. The bearing will be fitted on the shaft and
                            when the rear casing is offered up and pushed on it will sit inside this
                            recess in the casing.....

                            and this support ring will bolt it tight into that recess inside the box....

                            if you just dropped the bearing into the casing recess and bolted on
                            the cover above what you'll find is that it doesn't clamp the bearing
                            real tight in there. The bearing will actually be able to move back
                            and forth a little. So what you've got to do is measure how much
                            "slack" is in there and pack it up with shims so that the support ring
                            clamps the bearing tight when bolted up.
                            To do this first we measured the depth of the recess in the casing

                            and then fitted the bearing into the support ring.....

                            and measured how much stuck out (12.9mm)......

                            13.1mm of a hole minus 12.9mm of a bearing to stick into it is
                            going to leave you with 0.2mm of a gap in there, so, a 0.2mm shim
                            is fitted under the bearing before it's sat into the support ring like so.....

                            Now when all that is bolted together, that bearing is going to be
                            clamped nice and secure between the ring and the casing.
                            With the shims figured out and fitted between the bearing and the
                            ring, the bearing could now be slid onto the shaft.
                            The heads are cut off two long m6 bolts and these are screwed in to
                            two of the five threaded holes of the support ring, for reasons you'll
                            see in a while.....

                            centre of the bearing is heated with the heat gun and slid onto the shaft.....

                            and finally this little spacer is slid on.....

                            After that it's time to get the rear casing ready for going on.
                            Output flange seal is changed
                            (available after market for buttons, size: 40x55x8mm)......

                            and then the selector shaft seal (size:15x21x5mm).....

                            and then refit the reverse idler shaft stuff.....

                            the shaft sticks up out of the rear casing and onto it is dropped, bearing,

                            followed by the idler geared shaft.....

                            and then a fat little spacer with a corner cut out.....

                            As usual the cut out piece has to be in a specific location when the
                            rear casing is offered up to the box and the chances of it staying as
                            pictured when you lift the whole lot up is zero to none.
                            So, fat blob of grease on the back of the spacer and stick it in place in
                            the box instead....

                            The 2nd last thing needed in the rear casing before it can go on, is this....

                            There's five of these balls and three springs in total for the rear casing,
                            only one spring is needed at the moment, and it slides in through
                            a little drilling in the casing marked by the green arrow.
                            (you can just about see the spring in place, red arrow).....

                            And finally just before the rear casing is offered up,
                            bit of gasket poo and gasket is stuck to centre casing side....

                            And then just as your ready to offer the rear casing up, these 4 little
                            roller/spacer thingies (*may not be correct technical name)
                            are stuck into place on the selector shaft with the aid of four
                            blobs of grease....

                            don't be shy with the grease on those, the little fu*kers love to drop off
                            and head off for a wander while your shoving the rear casing on.
                            And then at long last the rear casing can be offered up,
                            but, it can only go on this far (because that'd be far to simple).....

                            quick check to make sure them 2 little m6 bolts that were screwed
                            into the bearing ring have come through the casing in the right place.....

                            and then the reason why the casing can't slide all the way home yet.
                            That little spring is in the way of the selector fork rod sitting into
                            it's final resting place.....

                            So, one of the little balls like pictured below is placed on top of the
                            spring in the casing and is pushed back into it's hole to let the rod by......

                            that sounds so simple when written, but in reality can provided hours
                            of entertainment for all the family. And when you've mastered
                            that one, it's on to the one next door, same idea, spring drops down
                            from the top into place, ball on top and squeeze down to allow the
                            next rod to push through, and, as if that wasn't challenging enough
                            you've also got to place a ball directly between the two selector shafts aswell
                            (that ball is hidden in this pic, the final pic in this sequence makes it a little
                            easier to see where they all end up!)......


                              and then finally the last one's, again a ball between the two shafts and
                              the final one sits on top of its spring and is depressed in it's recess
                              to let the shaft by (at this stage you'll either be a pro at
                              this or have set fire to the garage out of rage, if you look carefully
                              you might just notice the fire extinguisher fumes in the background
                              of this pic).....

                              when you've finally succumbed to the rage and decided to beat them all into
                              place with the sledgehammer this is where all the balls should end up
                              (red circles = the balls, blue circles = the end of the selector shafts)........

                              when they're all in place and all the rods are covering them, the casing
                              can be tapped the final half inch home. Then the collection of 5 little
                              plugs can be tapped back in, to cover all them drilling's in the casing.....

                              Then it's on to the bearing support ring and them two long m6 bolts
                              sticking out the back. The five bolts get a wee dab of thread lock....

                              The 2 long m6 studs sticking out the back should have kept
                              all the holes aligned allowing you to fit 3 of them into the 3 empty holes
                              ,finger tight, and then the two long bolts are taken out and replaced
                              by the other 2 proper bolts......

                              When they're all in then tighten them up evenly.
                              Front casing is nowhere near as dramatic. Stick the gasket on with
                              some gasket goo either side, heat the centre of it up so it sides on
                              easily over the bearings and then just batter it on.....

                              When it's on this little collection of crap.....

                              is battered into this hole,

                              After that the rear output flange goes on. A little gasket goo rubbed
                              on the inside of the splines helps keep it oil tight.....

                              special tool p/n 959rustybar makes a return to hold the flange while
                              the nut in the centre is torqued up.....

                              The nut no longer needs that brass type lock ring placed over it
                              next, as the factory revised the procedure to just use loctite on the
                              nut instead.

                              After that and it's back to the front end to do the final bit of measuring
                              and shimming.
                              The spacer ring is first slipped onto the bit of the input shaft bearing
                              thats sticking out.....

                              followed by the circlip that snaps into the recess cut in the
                              outside of the bearing.....

                              when all thats fitted, a few soft taps inwards on the end of the input
                              shaft to make sure it's fully home. (that circlip should be tight up against
                              the spacer ring, which in turn should be tight up against the housing.
                              With that done the little cover thats going to go over these bearings is
                              preped. The cone/tube "thingy" that the clutch release bearing rides on
                              (black yoke below) fits into the cover....

                              a tiny smear of gasket goo on the cover where the cone sits into
                              to keep it oil tight. The cone also has a notch on it so it'll only
                              sit in fully in one position....

                              with that in, the input shaft seal is fitted in to it (30x42x7mm, big money
                              from main dealer for some reason, available for buttons aftermarket)......

                              and then the measuring. The idea of this cover is that the 2 bearings
                              will sit into the two recesses in the cover. The recesses have to be
                              shimed so that when the cover is bolted on tight theres no wiggle
                              room left for the bearings. So to figure out what size shims are needed
                              first up we measured the depth from the face of the cover to the bottom
                              of the hole (the face of the cone/tube thingy)......

                              and that came out at 7.1mm, and then measured how much bearing
                              was sticking out of the box......

                              and that came out at 6.8mm.
                              So, from the hole depth..........................7.1mm
                              take away the bearing height...................6.8mm
                              and you get the size of shim needed ........0.3mm
                              Only theres one other thing to take into account,
                              that cover may have a gasket (some do, some don't)
                              and when you fit a gasket it brings the cover back another
                              tiny bit away from the bearing. So the manual says add
                              another 0.2mm for the thickness of the gasket.
                              So now the hole is..........7.3mm
                              minus bearing height.......6.8mm
                              equals shim thickness.....0.5mm

                              Same sort of deal for the bottom hole/bearing.
                              Measure the recess.......

                              That came to 5.2mm, and then measure how much the
                              bearing protrudes......

                              which came out at 4.7mm
                              So once again,
                              hole depth............................................. .....5.2mm
                              plus the bit for the gasket..........................0.2mm
                              equals............................................ .............5.4mm
                              minus the amount the bearing sticks out....4.7mm
                              leaves you with the shim size needed........0.7mm
                              Only it doesn't, because the manual says this bottom shaft
                              needs 0.1/0.2mm endfloat. Which means it needs a little space
                              to move around and stretch it's feet. So from the shim size of
                              0.7mm (which would have packed it tight) you subtract 0.1mm
                              to leave the true shim needed at 0.6mm (now the shaft has 0.1mm
                              of space to move around in as speced).
                              And if you understood all that, fair play to you, cause i'm writing it
                              and it's making fu*k all sense to me as I read it back.
                              Anywho, gasket goo'ed on, shims greased in place, it's time to throw
                              the cover on....

                              7 little bolts, 3 long for the top, 4 short for the bottom, get them the
                              wrong way around and the long ones will screw in the bottom
                              and right through the casing and burst your bearing inside, which
                              is nice.....

                              Last edited by xworks; 02-27-2011, 04:51 AM.


                                and ta-daaaaa.....

                                With the box overhauled it was time to turn the attention to the outside
                                bit's and pieces. First up, gearlinkage. When I got this car the gear change
                                resembled stirring a bowl of porridge with a large wooden spoon, it
                                was vague to say the least. I changed one little bit of the linkage
                                at the time, which helped, but I knew there was more to fix at some
                                stage. So now the day has come.
                                Theres 4 places where the linkage can get worn, and my car proving
                                as helpful as ever was w*nked in all 4 places......

                                position 1
                                This bit is probably familiar to most e30 owners as it's the bit
                                that wears most. It's cheap enough from the main dealer (p/n 25117503525)
                                and it's handy enough to change.......

                                Position 2
                                Was a bit surprised to find so much wear here. The bolt had
                                started to chew it's way through the bracket. Elongating the hole
                                and wearing down the bolt....

                                Position 4

                                This is the little ball the the gearlever rotates on. As the ball is metal
                                it doesn't wear, but the plastic bushing it sits in does.
                                New bushing main dealer p/n 25111220600......

                                Position 3
                                The little bush just under the ball on the gearlever.....

                                as you can see in the exploded part of the pic theres only a small
                                bit of wear here, but it doesn't take much to make the lever feel
                                sloppy. Theres no bush to change here, the only remedy is a new
                                gear lever. Thankfully I had a spare Z3 one which was good to go....

                                So, rob the post office on the way to the main dealer's......

                                Z3 lever fitted.....

                                new rubber bush in the end of the stabilizer bar as it was worn too....

                                fresh bracket and bolt fitted onto the new bush....

                                and then time to fit back the lower link. Two new plastic washers
                                fitted on the inside (p/n 25111220439 they're important and they're
                                also the cheapest part you'll ever buy from a main dealer)......

                                pop the link bar back in one end, with another plastic washer on the
                                outside before refitting the circlip........

                                slide in the other end of the link........

                                pop another fresh washer on......

                                and then the circlip......

                                If them circlips are loose sliding on, then replace them, there should
                                be a tight "click" as they pop on. If they fall off down the line, you'll
                                loose the ability to change gear, and it won't happen close to home,
                                it'll be in the middle of nowhere, it'll be dark and raining and you'll
                                be the tight arse fool walking back up the road, in pitch black darkness
                                looking for a lost clip that you were to tight to change. (yes, I wore that t-shirt).

                                And then finally, rebolt the stabilizer bracket to the box with the
                                two long bolts that are a pig to get to when the box is fitted in the car....

                                after that, reverse light switch goes back in with a new washer....

                                wires attached.....

                                and clipped on here.....

                                and here....

                                before magically reappearing inside the rubber boot.....

                                (the wires in the above picture were the old ones and since
                                fitting them and posting this up I've had a very helpful pm
                                from a member over on E30zone to say that the old wires can
                                short out due to age and in his case actually cause a fire.
                                The wires are now being renewed tomorrow.)

                                There was something not quite right about the geabox rubber
                                mountings, but I just couldn't put my finger on it.....

                                so I replaced them to be on the safe side....

                                bellhousing bolted back on along with the little bracket to support
                                the exhaust downpipe......

                                clutch fork, retaining spring and clutch release bearing back on.....

                                a lick of silver paint.....

                                and thats a brief description of how we overhauled my gearbox.
                                If you've made it this far, congratulations, most of what you've just
                                read is probably wrong. But sure there was nothing better on tv

                                Till next time.......