rear subframe & other questions

#1

Hey, I picked up a '87 325is a week last friday. I’ve been looking for a car to build for spece30 for a while and after acting too slow on this same car a few months ago, its recent new owner (the guy quicker than me) was transferred out of town and decided to sell.

So, I’ve ordered some suspension bits from bimmerworld and figured i’d spend the weekend taking things apart. I went to drop the rear subframe and even after removing the bolts that hold the bushings to the body, the subframe still stayed attached. It looked like the metal of the bushing was rusted to the washer, which again rusted to the body. I quick hit with the air hammer to the bushing between the carrier and the washer and both sides were loose. The washer also came off. but still attached to the body is a small section of the bushing’s metal. On the attached pic, its the very top of part #3. Besides heat, any suggestions to getting it out?

With the subframe removed, I was looking at it to see what it would take to press new bushings in. It looks like there are three dimples pressed in each side, two on the outside and one on the inside. Is this normal? Seems like it might make things a bit more interesting pressing the old bushings out.

Finally, I also removed the exhaust from the downpipe back. Has anyone found or fabricated a solution for (relativly) quickly removing the cat for the track, but still be able to re-install it for road use? I’m not sure if this car will ever see road use or if its even worth the effort, but still, I’d be interested if there is a good solution.

Thanks,
Gareth.

#2

here is an Oldie but goodie…
http://www.unofficialbmw.com/repair_faqs/subframe.html
this one has pics…
http://www.bmwe30.net/cgi-bin/datacgi/database.cgi?file=articles&report=view&ID=00098&Section=

#3

Thanks for the links. Definatly looks like heat is in order for actually getting the bushings out of the carrier. Unfortunatly I didn’t see any info regarding the dimples or what to do when the bushing doesn’t come out in one piece. :S I’m guessing the answer is heat there too - just still in denial.

Gareth

#4

I’ve been mulling over the exhaust question for months. Tomorrow I’m going to take the plunge and do the following: swap out my good cat for a gutted cat that has straight pipes installed within the carcass of a crap one. Replace the muffler with (2) 27" long 2" dia. Thrush glasspacks. I finally decided I didn’t want to break the bank paying someone to fabricate something fancy and I want to make noise. Not only will noise be part of the fun, but I want to hear my throttle position on the track. I was conflicted, however, because I don’t have a tow vehicle and therefore drive to the track. Maybe I’ll hate my decision, but I’ve already had a daily driver that became more and more of a track car, and I was stuck in the middle. The less I have to fiddle with when I hit the track, the better. I did consider getting an electronically operated butterfly valve installed right before the cat so I could either run the OEM exhaust system or just dump the exhaust before the cat in what amounts to a straight pipe set-up. Ultimately I just didn’t have the energy to pursue this more, nor the funds to pay for it (each glasspack was only $24 at Advance compared to $240 for the butterfly valve). I was also concerned with dumping heat and noxious gases underneath the car.

Good luck!
Sasha

#5

Well, geez, go ahead and post a thread on this subject the day before I get around to it. Just kidding. Yep, I’d found the same two articles.

Rather than removing the entire rear of the car, as the article on bmwe30.net suggests, would it be easier (or possible, more to the point) to lower the subframe by just removing the driveshaft and exhaust and dropping it down? And then, with the lowered subframe, replace the rtab’s at the same time? I’m just hoping to avoid removing the drive axles, diff (just got it back on a couple weeks ago!), brakes, etc… and it looks at least like this might be a possibility. I’m sure something must get in the way, though.

Steve

#6

nasaregistrar wrote:

[quote]here is an Oldie but goodie…
http://www.unofficialbmw.com/repair_faqs/subframe.html
this one has pics…
http://www.bmwe30.net/cgi-bin/datacgi/database.cgi?file=articles&report=view&ID=00098&Section=[/quote]

To anyone who used this method of removing the bushings - did you use a 5# or 10# slide hammer? (The link does not specify.)

#7

sdais wrote:

[quote]nasaregistrar wrote:

[quote]here is an Oldie but goodie…
http://www.unofficialbmw.com/repair_faqs/subframe.html
this one has pics…
http://www.bmwe30.net/cgi-bin/datacgi/database.cgi?file=articles&report=view&ID=00098&Section=[/quote]

To anyone who used this method of removing the bushings - did you use a 5# or 10# slide hammer? (The link does not specify.)[/quote]I was fortunate in that Steve brought his pimpy tool to VIR, and I have an extra subframe I carted down to get the bushings pressed out.

#8

I’m willing to loan my tool out to anyone who needs it. It’s been all over the country and pulled close to 10 sets of subframe bushings up to this point.

Send me an e-mail if interested to work out the details.

Steven

#9

I finally got around to replacing the subframe bushings & rtab’s a couple of weekends ago. I found that afterward I had a pretty significant decrease in rear camber, nearly 0.5 degrees, on each wheel. (I used the standard concentric rtab’s, not the offset bushings). I guess this would make some sense in that worn bushings would allow the weight of the car to tilt the trailing arms inward. Did anyone else who’s done this have this happen?

#10

Yes, solid or nearly solid subframe bushings and diff mount help a TON in the handling. The balance is roughly the same on my current car as my old one. But the rear end is alot more stable with harder bushings and the black poly diff mount. When you keep that sucker from moving and twisting it really helps the handling.

I’ve found that when you get the "stuck" subframe it’s easiest to simply break the aluminum sleeves in the stock bushing off to get the subframe out of the way. They use heat, monkey snot, and a chisel to clean out the remains.