guidance for rtab / subframe bushing replacement

#1

All,

Anyone have a good source of step-by-step information on replacing rear trailing arm bushings & subframe mounts? I found an article on bmwe30.net (http://www.bmwe30.net/cgi-bin/datacgi/database.cgi?file=articles&report=view&ID=00098&Section=05), which provides some good info, but I was hoping to find another source for comparison. I know I need to do this, and I’m sure I can figure it out, but that’s a whole lot of parts to be removing / reinstalling for someone who didn’t know what a halfshaft was 18 months ago!

Thanks much!

Steve

#2

Here’s a good reason for why I’m asking this - I found a second article regarding replacing the subframe bushings (but not the rtab’s) which indicates this can be done w/o removing much at all. This article is found at: http://www.unofficialbmw.com/e30/suspension/e30_rear_subframe_bushing_removal_guide.html

I just don’t want to start pulling off parts w/o knowing exactly what needs to be removed to get this done - as easily as possible!

Steve

#3

I’ve just gone through the subframe & trailing arm removal (and had a couple questions over in Preparing to participate.) This link was suggested in addition to the bmwe30.net one.

http://www.unofficialbmw.com/repair_faqs/subframe.html

I read "Once the pins are out the subframe simply drops out. " from the bmwe30.net article and laughed. The author wasn’t working on a michigan car, mine required an air hammer and I still have parts of the bushing to remove (see other thread for details.)

With regard to the process used to remove the subframe, I did pretty much what the bmwe30.net link describes. I’m sure the unofficialbmw one could work but remember their recipe calls for inserting a 36" rod into the bushing - most people don’t have 36" of working space under their car. Granted it seems to be for the improvised slide hammer, so you might get away with a shorter rod, but space under the car could still be an issue.

Gareth.

#4

Thanks - good info there. I guess that following the method in the second link that I’d posted would not be an option for someone wishing to replace the rtab’s at the same time. That, it looks like, requires removal of the whole subframe?

#5

Steve,
If you mean to say that you need to remove the whole subframe to do the RTABs, that is not actually correct. It is the easier way to do it. If you looked at the RTAB bolts and the limited space to work in , you will see. One thing I noticed in the car I stripped for parts was that the subframe bolts are sort of press fit in, and the tops ob the bolts are covered with goop…like caulk that I had to cut out before I was able to knock the bolts out.

#6

Steve,
If you mean to say that you need to remove the whole subframe to do the RTABs, that is not actually correct. It is the easier way to do it. If you looked at the RTAB bolts and the limited space to work in , you will see. One thing I noticed in the car I stripped for parts was that the subframe bolts are sort of press fit in, and the tops ob the bolts are covered with goop…like caulk that I had to cut out before I was able to knock the bolts out.

#7

Steve,
As an update… I just removed all the bushings tonight, having removed the trailing arms and subframes last weekend. For the subframe bushings, first I rapped on the metal part of the bottom of the bushing with the air hammer, then I fit a puller like the pictures on bmwe30, then I added a bit of heat (only propane, so nothing crazy) as I added heat, I could see the bushing starting to move. I then pushed it out the rest of the way with the puller. The rtabs didn’t need any heat.

New bushings (and other fun stuff) should be here in a couple days, so I’ll report on installation early next week… …hopefully.

Gareth.

#8

Gareth - thanks for the update. Did you see my post on the thread that you’d started (which I should have followed, had I seen it!) regarding whether it would be possible to drop the subframe by just disconnecting the driveshaft? Do you think this would work? And if so, any thoughts on whether this might be an easier way to go vs. removing the diff & everything else ala the directions on bmwe30? Thanks!

Steve

#9

Steve,
Sorry, I guess I missed the post on the other thread. In any case, I think it’ll work fine if you remove the exhaust & drive shaft - then drop the subframe, diff & trailing arms as one assembly. Just remember that you’ll need to still disconnect the brake lines and wheel speed sensors if you want to get the subframe more than a couple inches away from the car.

I think the reason for removing the diff is if you have the driveshaft in place, it’s hard to move the subframe around the driveshaft and down because of clearance to the rear of the diff. (I say hard, I found it impossible.) That said, with the diff removed, you’re wrestling a lot less weight so that makes it a little easier too.

One nice thing about removing the drive shaft is there you don’t have to worry about it resting on the fuel tank’s connection line. I put a piece of safety wire and a jackstand in place to ensure this didn’t happen.

Gareth