Rear suspension in a weekend?

[LateFan]

Hey - can a guy replace the rear subframe and trailing arm bushings by himself in a day / weekend? Or is this a two-man job?

I'll probably have to take it to a shop with a press on Monday, so it really isn't happening in just a weekend anyway.

Thanks -

[Som]

I would say if you've got someone who's familiar with the process, a weekend would be fine.

It took me way longer than that, but I replaced a ton more things when the subframe was dropped. And I'm slow. And I like to clean / respray things. And I'm slow.

After I'd reinstalled the subframe, I over-torqued my aluminum bushings and had to drop/reinstall it again. I remember the 2nd time the drop was extremely quick to drop (hour, maybe?).

Here's the general process, with my "pain points". I'm sure others can chime in if there are easy ways to get around the pain points.

1) You're going to disconnect all the wiring (ABS/speedo sensor) and the inside brake lines
2) You're going to disconnect the e-brake cable -- I was replacing my rotors anyway, but I'm not sure there's an easy way to unhook the cable without getting to the parking brake mechanism under the rotor. Removing the rotor could be a pain point because of the set screw and potential rust that has form between the rotor and the flange. Obviously you'll need to remove the caliper to do this -- just leave it hanging somewhere without putting strain on the hydraulic hose. If you end up exposing the parking drum brake like I think you'll need to, I'd recommend taking a photo of it before you start messing with it, so you know how to put it back together. I found there to be a bunch of variations on the internals here (different spring types and drawings not being clear on which of the springs have the kink in it, etc etc).
3) Loosen the lock nut on the drive-shaft just aft of the center bearing.
4) Remove the 4 nuts attaching the after drive shaft to the diff input flange. Having a 2nd person to set/release the e-brake while you're under the car helps with this.
5) Slide the aft driveshaft towards the front of the car as much as possible -- disengaging the bolts from the diff input flange.
6) At this point, you'll want to support the center of the diff with a jack. Placed in the right spot, the entire rear subframe/diff balances perfectly at this point.
7) Remove the bolt/nut attached to the diff bushing.
8) You're going to remove the subframe nut (22mm nut).
9) You're going to unbolt the side frame supports for the subframe bolts.
10) You need to get the subframe bolt out. This is another pain point, particularly if the car has never had them removed. These are long bolts that drop down from under the rear passenger bench seat. There's a foamy sealant that comes from the factory for covering the hole these go into. You have to cut/dig that stuff out. The usual way for getting the bolt out is to spin the nut back onto the bolt partially to protect the threads, then whack it with a mallet/dead blow/sledgehammer.
11) Once out, there's not much else holding the subframe to the car -- but it's not super easy to drop down. This is another pain point as parts of the sides of the body will prevent you from straight dropping the subframe, as will the bracket for the diff bushing. Also -- be careful of the driveshaft -- it may be disengaged from the diff, but it's still in that big hole in the subframe. If you drop the weight of the subframe/diff onto it, you could cause some damage to the shaft, the center bearing, and the pipe that connects the fuel tanks (mine had this, might be an '87 thing that's not on the newer E30s). Either way, getting the subframe off was a pain point. One thing that helps getting a good feel of the weight of the subframe and leaning it backwards as you're lowering it to help clear the driveshaft.
12) Remove the trailing arm bushing bolts.
13) Torch then cut the "bulbous" part of the bushing before using a trailing arm bushing removal tool to remove the bushings themselves. The tool is basically a threaded rod with nut/cap on one side and a nut/capped pipe on the other. Tightening the nuts will press the bushing out. See here: http://www.akgmotorsport.com/rtabremove.html. I want to say this is typically described as a pain point, but with the tool and liberal use of the torch, it was pretty easy.
14) Use the same tool (typically) to reinstall/press the new bushings on. Not sure if you're going with poly or stock. With poly you'll want to make sure to grease up every part that moves -- the rod-to-bushing interface and the bushing-to-trailing arm interface. Not sure if grease is necessary for the stock bushing -- guessing it is.
15) Insert both trailer arm bolts for a side before tightening down.
16) For the subframe bushings, I made a little tool that fits into the notched holes of the bushings to press them out. There's a good thread here (http://www.bimmerforums.com/forum/sh...bushing-puller) about making a tool out of a modified Craftsman puller and a cheap Harbor Freight part.
17) I used a hydraulic press to push the new aluminum bushings back in. Not sure how different poly/stock bushings would be here.
18) I'd probably replace the diff bushing here, too. I think I torched the hell out of it, then notched the outer ring with a dremel and pried it off. Used a press to get an aluminum one in.
19) Now you're ready to reinstall. Line up the subframe and lift with the jack. This is another pain point for the same reason dropping it was a pain point -- lining things up so that a) you get the drive shaft into the hole, b) the subframe bushings line up with the body, and c) the diff bushing slides into the diff bracket on the body. Again the "lean it back then slowly lift/lean it forward" strategy worked for me here. Another pain point for me, even after everything was "back in place", was that the bushing rods didn't slide into the holes in the body -- it was almost as if the subframe was 2 or 3mm too skinny. What helped a bit here was using a file to taper the rod a bit to help it slide in. I'm sure other people have their tricks, too.
20) Attach the diff bolt (loosely).
21) Drop the subframe bolts through the body and through the subframe bushings
22) Attach the side frame supports
23) Loosely attach the subframe bolt nut
24) Slide the driveshaft bolts into the diff input flange. Loosely put the nuts on.
25) Tighten down the subframe bolt nut
26) Tighten the diff bolt
27) Tighten diff input flange bolts
28) Reattach the inside brake lines
29) Reattach the ABS sensor wires
30) Reattach the speedo sensor plug to the diff
31) Reattach the e-brake cable. (Pain point for me because I had taken my entire parking brake apart and it took me a while to figure out how it all went back together again)
32) Reattach the rotor, set screw, and caliper.

I did this about 9 months ago, and this was all typed up off memory, so I may be off on some of the bits, but I think I got the gist of it. If it seems like something that you can take on in a weekend, go for it! :)

Som

[LateFan]

And I'm slow. And I like to clean / respray things. And I'm slow.

^^^ This is me as well!

Thank you - good to see where you had troubles. Here are some I was going to use:

http://www.e30tech.com/forum/showthread.php?t=6480&page=6

http://www.r3vlimited.com/board/showthread.php?t=78367&highlight=subframe+lag+bolt+bushing&page=7

http://www.r3vlimited.com/board/showthread.php?t=74184

The car is dry, no rust, and not too gunked up underneath. That doesn't mean any of this tuff is going to come out easily!

Thanks again -

[rturbo 930]

13) Torch then cut the "bulbous" part of the bushing before using a trailing arm bushing removal tool to remove the bushings themselves. The tool is basically a threaded rod with nut/cap on one side and a nut/capped pipe on the other. Tightening the nuts will press the bushing out. See here: http://www.akgmotorsport.com/rtabremove.html. I want to say this is typically described as a pain point, but with the tool and liberal use of the torch, it was pretty easy.

I wouldn't use a torch on the bushings. It just leaves you with a sticky rubbery mess. I'd trim them as shown in the DIY, although actually, I don't remember having to do any trimming at all to get them out, and they came out pretty easily.

Getting the trailing arms with new bushings (I used 2 piece IE bushings) into the subframe was a bitch though. If I were doing it again, I would use one piece bushings if you're going with poly.

[LateFan]

We will be using all OEM / Lemforder.

[Som]

One thing I was just thinking about. I remember the driveshaft was a pain to work around with the dropping/raising of the subframe.

I remember the first time through being worried about removing the center bearing and messing up the alignment of the driveshaft. I had all the exhaust/heat panels off the bottom of the car, so I don't know if these would interfere, but I would look into possibly removing the 2 center bearing bolts and carefully pulling the driveshaft from the rear-subframe hole altogether. Before I removed them when dropping it the 2nd time, I hit the 2 bolts and bracket with spray paint (and let it dry) to make sure I could put the center bearing back on in the exact spot. You're not supposed to pivot the driveshaft too much on the center bearing, but I think it should be possible to get the clearance you need without any extreme angles there.

Then you can drop/raise without worrying about the drive shaft. When everything is back in place work the driveshaft back in place and bolt everything down.

Regarding the torching -- obviously if you can do it easily without torching, by all means! :) Wasn't too messy for me (it kinda just becomes crumbly and brittle). I guess I didn't think the "mushroomed" part would squeeze if I didn't remove it, and I much prefer removing burnt rubber than trying to saw/slice hardened rubber. To each their own, though! :)

Som

[LateFan]

"in a weekend." HAH!

I got the subframe out, axles off, trailing arms off, most bushings out. Was trying the slick FredK simple way to get the subframe bushings out but it just wasn't working, so I pulled the exhaust, dropped the subframe, and I'm doing it all on the floor.

Getting it all back together and lined up and back in place seems like it'll be quite a chore. Especially lining up the driveshaft flange.

[Som]

Consider dropping the CSB. Move the driveshaft out of the way completely, put the subframe back in (I had enough of a problem as it was with this part without worrying about the driveshaft), then put the driveshaft back in.

Som

Edit: Oh, and that's still good progress in a weekend in my book! :)

[LateFan]

OY! Whatta lotta work for an old guy!



Empty..



Back together with all new bushings...now to teeter totter it on a jack....



Took the bushings out last night late, dropped off pieces at a shop with a big press this morning, he had them ready by 5.

Those sway bar links are a pain to get back on - force doesn't work. I tried the boiling water trick and some dish soap and they popped right on!

[LateFan]

It's in!! It's a miracle!

Took about 6 attempts, including having the thing slide backwards down the jack arm. Tried so many ways to have it tilt back and still be stable, but then how do you rotate it forward once the driveshaft is inside the subframe? 2x4 blocks, 2x6 wedges....Argh. I tried going in at an angle. I tried FredK's rocking back and forth side to side.

I finally took off the heat shields and pulled the center driveshaft support, but the driveshaft doesn't kink much (Mine is an '86es, so it has a crossover pipe between the tanks).

It JUST. WILL. NOT. CLEAR the driveshaft studs AND the wheel well lips at the same time! So as a last resort, I popped the driveshaft studs out of the flange - they're just splined studs and came right out.....duh.

That gave me just enough space to clear the end of the shaft and get the pins up near the holes. Some careful wiggling and jostling and SHOVING and up only a 1/4" at a time, and it slid right up into the chassis pin holes. Rotated it up into the diff mount and put those bolts in so fast before anything moved! (TIP - put those driveshaft studs back in before you've got the crossmember rotated and pushed forward, or you won't be able to reach in there for the top ones.)

I used a pry bar to ooch the crossmember sideways to get the subframe bolt holes to line up.

That may have been the hardest thing I've tried on a car.

My conclusions (for my skilz level):
This is a two-man job, even if one is bored most of the time.
It is more than a weekend job. I still have to hook up the driveshaft, heatshields, wires, brake lines, bleed the brakes, exhaust re-installed...what else....

Go very slowly and carefully. Keep valuable body parts out from under any heavy balanced metal object - it can slip without warning. Spend the extra time to pull things that are in the way - it will go much more smoothly. Don't get frustrated, just concentrate and keep trying.

[Som]

Nice!! :)

Did you try rotating the driveshaft when you dropped the CSB? I'm wondering if the angle of the shaft dictates how far it'll "fold down". I could have sworn mine cleared easily and I've got the crossover pipe, too. Same goes for reaching the top flange bolts -- that's where 2 people make things faster -- one person disengages the tranny so you can rotate the drive shaft, then reengages it so you can tighten the nuts down.

Otherwise, I think you made great time for a first pass at it! :)

Som

[LateFan]

Nope, but I could shine a light forward to the tranny and see that that U-joint was already jammed and it wasn't going to bend any more than it was. Taking the flange studs out was the ticket - didn't realize they were just pushed in.

Rear end is nice now with all OEM rubber. Feels solid.

Thanks for all the advice. (Also note - I cleaned nothing, I sprayed nothing. That's a first - I just wanted it back in...and my son is leaving on a 1000 mile trip tomorrow..))

[Som]

Sweet. It looks like you disconnected the parking brake cables from the handle vs. from under the rotor. I totally didn't think of doing that. Would've helped the 2nd time around since I had re-assembled the parking brake assembly before I destroyed the first subframe bushings I put in by over-tightening. I could have just done what you did instead of disassemble/reassembling the parking brake.

Som

[LateFan]

The parking brake handle way is slick - 2 8mm nuts, slip the cables outboard from under the handle U channels, and the whole thing slides right out the tubes in the back.

I drilled and cut the center diff bushing out. I bent and completely stripped a threaded rod and several (hardware store) nuts trying to get the TA bushings out. I took it to a shop I like and it took him 2 hours of labor to get the rest out and the new ones in. And he said some of them were a lot of work. Worth it.