Another rear subframe thread.

[Jean]

Hi! I was able to drop the subframe / rear diff / trailing arms out, it did take me about 3 hours under the car w/out a lift and i am no mechanic by any means.

I pulled the parking brake cables from under the car after removing the two nuts on the parking brake assembly in the car, no problems here. There was just not enough room under the car to get the trailing arms out w/o removing the subframe, maybe if the car was on the lift it would be different... I removed the 4 nuts holding the diff flange to the drive shaft. Disconnected rear sway bar end links from the trailing arms and removed the two bolts holding the shocks. I then partially removed the two 22mm nuts holding the subrame and it started to drop down on it's own weight. I then removed the brake lines, I actually just cut the soft lines as i'll be replacing them and didn't have a flair wrench with me.

Now here is where I ran into a little problem. I didn't want to drop or move the rear axle since I wasn't sure what I was getting myself into. I could not drop the rear subrame with the rear diff attached to it because the bolts holding the rear axle to the rear diff were getting caught and were in the way. I let the two 22mm nuts on the subrame and 1 bolt through the rear. diff cover hold the whole thing in place while I removed the 4 smaller bolts holding the diff and the hex bolts on each side and dropped the diff. Once the diff was out of the way I was able to drop the rear subframe w/o much trouble.

I haven't dissasembled the rear brakes yet..

[Mike325]

Sounds good:D

[Jean]

What are the weak points on the rear trailing arms and/or subrame, is it just the little tabs for the rear swaybar ? M trailing arms actually have an extra piece of metal welded between the / \ bars turning it somewhat into an "A" shape.

[Mike325]

I am not sure of any weak spots except for the mentioned rear sway mounts are the TA.

[Jean]

Here is a picture, what was the reason behind this ?

[mops]

Hey guys.

Great thread :)

I started dropping the subframe on saturday. I'm kinda going slow, but many of the bolts where rusted and required special care during removal. I'm quite happy with the fact that I didnt break anything yet (knock on wood :) ), but will have to replace few bolts with new ones so far...

anyways, I'm stuck in the same exact spot and this thread begins :) 1 of the bushings came off nicely (rubber was cracked to pieces and essentially inner and outer part of bushings were disjoint). But the other one holds strong. I can't break it loose. I hammered the bolt from underneath and it doesnt move. I even jacked the whole car by that subframe bolt and it didnt move either. I do not have rubber/goo on the top side of the bolt - it's nice and clean there, but the thing wont move... Today I'll try to jack it up again and then hammer the chasis from the top.

what i don't understand is that the inner part of bushing sits on that bolt. it is screwer in or just pushed in ? if I apply force will it slip out without damaging the bolt ? The side where the subframe got dropped, the inner part is stuck hard on the bolt and wont move...

wierd thing is that I got bentley and 3 other e30 manuals and none of them cover the rear subframe topic....

[Mike325]

You are talking about the two large bolts that hold the subframe to the body of the car? The 22mm ones? They do come out of the car from the bottom to the top, under the rear seat. I am suprized that it can not come out. Usually, you just hit them with a hammer a few times to knock them up. Have you tried spraying some rust penatrant on the top of the bolt? Maybe that will help. Maybe you could heat up the top of the bolt as well with a torch. Then have someone hit it up as you do that.

[mops]

Update.

I got those bolts out by hammering from the underside of the car - they came out, however inner part of the bush was still stuck hard.

I ended up cutting through tthe rubber bush by using specially made rounded chiesel and using carjack to force it through the rubber. Once I dropped the subframe, I got the inner part of the bush (stuck to the car) by whacking it with a hammer few times.

I removed trailing arm bushes by using 1/2" 32mm deep socket, m20 headbolt and a matching nut to construct a puller. worked great.

subframe busches were really hard to remove. between the outer part of the busch and the subframe there's a thin layer of rubber, that absorbs all the sofce of impact, so forget about hammering it. you need either a press, or a custom made puller or what i did, which is to collapse the busch to the inside.

I made a cut half way through the outer bush part with a hacksaw. then carefully happeded in a thin screwdriver beterrn the subframe an outer bush tube. then a bigger screwdriver. then bigger and it fell out by itself... the other one i was trying to save time and didnt bother to cut it just started hammering in screwdrivers and such -> not a good idea. wasted 3 screwdrivers, spent more time mucking around but got it out aswell. another thing i did was to put the collar side of the bushing into vice and collapse it that way.

Now I'm working on supports for the swaybar mounting points. I'm thinking about modyfying it alltogether... inclusing a swaybar...

[sakdbma]

Update.
subframe busches were really hard to remove. between the outer part of the busch and the subframe there's a thin layer of rubber, that absorbs all the sofce of impact, so forget about hammering it. you need either a press, or a custom made puller or what i did, which is to collapse the busch to the inside.

I made a cut half way through the outer bush part with a hacksaw. then carefully happeded in a thin screwdriver beterrn the subframe an outer bush tube. then a bigger screwdriver. then bigger and it fell out by itself... the other one i was trying to save time and didnt bother to cut it just started hammering in screwdrivers and such -> not a good idea. wasted 3 screwdrivers, spent more time mucking around but got it out aswell. another thing i did was to put the collar side of the bushing into vice and collapse it that way.

Like i said on BS dude, blow torches are your friend :D I just melted the fuckers out!!

And yea about three posts up is a pic of re-enforced T.A's what does that improve/change if anything?

[rcko]

Read this thread and others and were helpfull... To remove the SF from the car I ended up using 3 jaw puller and then a crow bar to remove the stuck alumn insert. To remove the bushing from the SF I used a press and pipe inserts with lots of liquid wrench.

I really recommend to folks that while they are swapping these bushings out to consider doing the a arm busings, diff bushing, brake lines, diff maintenance, axle, brakes, drive axle, and anthing else back here. You will have soo much better access to alot of the components back here with the subframe off that it just makes sense.

Also, dont forget to install those metal washers back in. I did, dont know if it will be an issue since I went with the super hardest polyurethane bushings that AKG sells there is no slack/play. But yeah, dont forget them... especially if you are using the soft rubber softer urethane.

While disconnecting the brake lines, make sure to really closely inspect the metal hardlines. IF there is any corrosion, spray then good with a penetrant and proceed very carefully to remove them. I didnt and had one actually rip off. I got lucky there was enough slack in the flex line to allow for the fix to be nothing more that a re-flare on what was left of the hard line, but be carefull. Support the hardline and lossen the flex line instead whenever you can.

[xLibelle]

nm

[FredK]

A little story of skinning the cat a different way.

I wanted to remove the subframe without removing the rear section of the exhaust, which could introduce its own set of problems. But, my trick is applicable to anyone wanting to quickly remove the bushings from the body (2-3 minutes a side).

So, to start, I removed the subframe rubber hanger, and loosened the straps so the exhaust could hang down a little. I supported the exhaust tip with a jackstand, to avoid straining the back section. I removed the M14 studs that pass through the center of the subframe bushings.

I think rocking the subframe back and forth will place the exact kind of shear loads on the tops of the bushings that will cause the top of the bushing to break off in the body. So, one of the ways to do this is to tap the bottom of the bushing with screw threads, screw a bolt into the bushing, then pound on the bushing from up top.

Good luck finding an M16 tap and bolt. An M16 tap ain't cheap either. You could use a 5/8-11 tap. But these cost $25. Screw that! :nice:

I decided to get a 5/8" lag bolt (less than two bucks at Lowes) and thread it into the soft aluminum bushing and pound it from up top. Worked like a charm. I put a 1 foot 3/8" extension inside the subframe pin bores while inside the car, and pounded on it a few times to break the bushings free.

[NC325iC]

so you put a bolt in the bushings itself and put a 1 foot ratchet extension on it from the inside and just beat away at it... seems alot easier than the way i did it (more or less sawzall method)

[FredK]

Yep, that's what I did.

[GoKart]

Yep, that's what I did.

How did you then get the new ones in... ?