To Shim A Driveshaft Properly...?

[95BMWIC]

I have spent the last 3 hours searching threads from a multitude of forums on the topic of shimming a front driveshaft. Here are a couple of the better threads: (There are links of more inside the first thread)..

http://e30tech.com/forum/showthread.php?t=110645&highlight=front+driveshaft

http://savarturbo.se/~mattias/motor/pictures/ix/shim/


Here is what I have deduced so far...

Shimming with washers is a short term fix - however the factory centering flange (centering pin spacer for the front driveshaft) remains and relatively no vibrations are reported when driving.

Shimming with a 1/4 plate is possible, however the centering pin spacer cannot be used - it may engage barely - however it does not "lock" into the driveshaft (see pic of driveshaft and centering pin plate contours) and vibrations have been reported...

Also there is some debate on thickness..
Also you need to locate a machine shop - this is not something you can order... have not located what price this might be..

Shimming by using a bigger guibo (such as rear flex disk for the 325ix) Specs found here:
http://www.e30tech.com/forum/showpost.php?p=1235260&postcount=11

This seems to be preferred but again the centering pin will not reach and if used and will cause the heads of the bolts to hit the transmission case cover - which is suggested you "grind down"..

Chris 325ix suggests that an X5 center pin may fit through the thicker rear 27mm E30 325ix guibo and be used to center the driveshaft.

This seems to me the best way to shim the driveshaft if the X5 pin will work...

I would like to hear from the people who have shimmed their driveshafts with some recommendations.. A lot of the threads are incomplete without people reporting back after a few thousand miles to whether they had trouble or not..

Does our moderator Nando have an opinon? Your thoughts on the X5 centering pin.??

[95BMWIC]

To reiterate my dilemma I have a good front ds (thanks to LuckyH) but my coupler splines are worn. I plan on trying the loctite fix, however I am waiting for information from loctite.. Will post process if anyone is interested in trying this.. Its a daily driver so many miles will be travelled...

I am going to try this, because in reality I figured if it doesn't work, I am only out a few hundred and I would be buying a rebuilt TC anyway.. If it does work, then I precluded the $1500 - $1700..


Robbed from earlier posting..

X5 centering pin - part number.. (centering flange)

http://www.realoem.com/bmw/showparts.do?model=FA53&mospid=47745&btnr=26_0175&hg=26&fg=10

[nando]

I plan on buying the x5 centering pin, but the price jumped recently.

[flyboyx]

To reiterate my dilemma I have a good front ds (thanks to LuckyH) but my coupler splines are worn. I plan on trying the loctite fix, however I am waiting for information from loctite.. Will post process if anyone is interested in trying this.. Its a daily driver so many miles will be travelled...

I am going to try this, because in reality I figured if it doesn't work, I am only out a few hundred and I would be buying a rebuilt TC anyway.. If it does work, then I precluded the $1500 - $1700..


Robbed from earlier posting..

X5 centering pin - part number.. (centering flange)


The x5 centering flange can be found at the junk yard.

I have also heard about the locktite repair, but with the dynamic load in that area,I have my doubts that it could last. I guess it's worth a try.

Wouldn't it be better to just weld an old driveshaft to the splined output? This would likely have the best chance of holding together. Even better but more expensive would be to get the ds lengthened so that it comes to within about 1/8" of the back of it's socket in the output.

http://www.realoem.com/bmw/showparts...75&hg=26&fg=10

[flyboyx]

Ah....f'ing IPad. My response is burried in your quote above.

[nando]

brian.. you find an x5 center pin in a junkyard, buy it for me. we don't have any real junkyards around here anymore, so it's not even really a consideration to me. although I do like shiny new parts, it's $55 at the cheapest place I can find right now. used to be only $30. I'm definitely going to use it one way or another - already have a thicker flexdisk to use with it.

I also don't think the loctite repair will work, but you may as well try. all the docs I saw linked were for systems very different from ours, and it was being used in a very different way.

[nando]

FWIW here's a shot of the thicker flexdiscs next to the stock front flexdisc:



I have two, one is just an original rear flexdisc, the second is an X5M part number that I picked up stupid cheap. it's dimensionally identical to the rear ix flexdisc. the other reason I took pictures of it, is I believe it's a counterfeit.

Wierd huh? I got it super discounted, there was a shop a while back that emptied it's warehouse of old BMW stuff. I didn't even notice until I had it side by side the one from my ix- the BMW stamp and part # are filed off the rubber, and the casting quality is noticeably worse.

What I believe to be the fake one is on the left..


filed off area where the BMW logo goes..


filed off BMW part #


you can sort of see in the picture, but it's harder to tell, that the quality of the rubber casting isn't the same. I know there are counterfeit BMW flexdiscs out there (and other BMW parts too), but I've never noticed one before. I imagine they just molded a real BMW flexdisc and filed off the part # after the fact to avoid trouble. the rest of the markings are indentical. From what I know, the fake ones don't have the same internal windings and aren't as strong. I'm not sure I'll use it, I think I'd rather take my chances with the other one which is used but in great shape.. and definitely 100% made by BMW.

Oh, the "fake" one has a giant ugly white "made in germany" marking on the side, that you never see on real BMW parts. None of my original flexdiscs have a mark like that. I also know that the chinese copycats like to put markings like that which are actually fake parts (fuel pumps are a big one, real Bosch pumps are made in austria, not germany). be careful out there...

all the other parts I got appear to be genuine. the shop probably didn't even realize it. how could you know unless you held it up next to an original?

[5Toes]

So X5m guibos fit e30s..?

[nando]

where's a facepalm.jpg when I need one?

why don't you read the thread. ;)

[shifty]

Here you go, freshly stolen:

[95BMWIC]

I haven't made up my mind on the loctite fix yet.

I left a message for the rep to call me, but haven't heard back. I will post the conversation once I hear. I want to know the bonding strength and what kind of pressures (torque) it can withstand.

I am exploring the loctite solution as I believe this may provide a better solution than welding the shaft to coupler. When you weld the coupler, I am afraid that the seal could be damaged by the heat causing it to fail and TC fluid to leak out (correct me if I am wrong).

I am hoping a bond can be created in which the damaged coupler splines can be repaired to such a point that there will be little friction between the coupler and the new drive shaft. Also with the addition of the guibo spacer, the splines would be engaged and locked with new splines helping the situation. Finally, I would be able to brake the bond and release the shaft much easier than the welded route..

But of course, I am only contemplating this.. I need to talk to the rep first..

I am currently searching for a used X-5 pin, but I am afraid nando is right, it is easier said than done..

I believe the thicker guibo and the x-5 pin offers the best solution so far.

[flyboyx]

I haven't made up my mind on the loctite fix yet.

I left a message for the rep to call me, but haven't heard back. I will post the conversation once I hear. I want to know the bonding strength and what kind of pressures (torque) it can withstand.

I am exploring the loctite solution as I believe this may provide a better solution than welding the shaft to coupler. When you weld the coupler, I am afraid that the seal could be damaged by the heat causing it to fail and TC fluid to leak out (correct me if I am wrong).

I am hoping a bond can be created in which the damaged coupler splines can be repaired to such a point that there will be little friction between the coupler and the new drive shaft. Also with the addition of the guibo spacer, the splines would be engaged and locked with new splines helping the situation. Finally, I would be able to brake the bond and release the shaft much easier than the welded route..

But of course, I am only contemplating this.. I need to talk to the rep first..

I am currently searching for a used X-5 pin, but I am afraid nando is right, it is easier said than done..

I believe the thicker guibo and the x-5 pin offers the best solution so far.

well, this would only be the case if you replace your driveshaft with a good one that hasn't been rounded off. if you stick the old rounded off driveshaft in the socket where the splines are already rounded. you are simply engaging your rounded splines into the good portion. that certainly won't last long. kind of like chasing good with bad.

i think the e34ix centering plate would work too. its a shame that realoem lists this one at about 200 bucks.

[BonnschE30]

I'm running a rear guibo up front at the moment without a centering pin. No vibrations or looseness or problems thus far, probably 1000 miles so far. In all honesty I'd really like to see if the X5 centering pin works before I buy one.... Let the flaming begin?

[nando]

I'll have one to test when my order from blunt comes in.

I think the centering pin is mostly to keep it straight while bolting it down. it's like hubcentric wheels. I haven't had hubcentric wheels in 3 years and I have no vibrations at all.

[nando]

X5 center pin came in - it's a *perfect* fit. It was about $50.