Rear Suspension Overhaul Part I: Trailing Arms, Wheel Bearings and Surviving a 20 Ton Shop Press.

The rear overhaul was a tall order. I started in early 2013 and finally finished in April 2014. There were many contributing life factors, but overall I tracked most of my hours. Total time spent in the garage on the car doing odds and ends was well over 60 hours. So it was about 2 weeks of work straight. If you actually had that time and all the correct parts.

Looking at it in those terms makes it seem like a much smaller job than it actually was. Having gone through it all I would probably do things a little differently in the future. I'll go over that.

Step 1: What's the service consist of?

Here's what I changed just on the rear suspension.

New trailing arm bushing (RTAB) (e46 split design Meyle HD/TCK Limiters)
New subframe bushings (Bimmerworld solid aluminum)
New upper and lower rear control arm ball joints (OE BMW/Lemfoerder)
New rear adjustable lower camber arms. (Turner Race)
New wheel bearings, snap ring, nut (FAG)
New differential bushings (Turner solid aluminum/delrin front)
New sway bar bushings (Lemfoerder)
New wheel bearing and associated hardware (FAG)
New boots/grease for axles R&R (GKN LOEBRO)

Weld reinforcements for the RTAB pocket (AKG)
Weld reinforcements for the rear sway bar attachment (TMS)

Powdercoat all parts

Step 2: Start unboltin' shit

Obviously to get at everything you got to drop the exhaust. After that was down I got a better look at what we're dealing with.

Axle, subframe and diff with 20 years of dirt on it.

Tired sway bar bushing.

RTAB that probably has never been changed.

Dirt.

Cracked front differential bushing.

We'll see more as the parts come off. First order of business is to remove the axles. I'm not going to pretend like these are the simplest things to take off. The T-12 or T-14 (it's probably T-13 if that exists) star nut head is a pain in the ass. They're really easy to strip. I didn't use air tools at first for this very reason, but I found that a slow crank was actually worse than an impact. After ruining two bolts I impacted the rest off with no problem. Don't be afraid of air tools here. Also helps with immobilizing the drive-train.

I had to use one of those craftsman extractor style sockets you see here because I was super smart about rounding off the head on a few bolts. The bolts are $10 each from BMW by the way.

Once the axles are free you can give them a whack with a big hammer and they should come free.

From here I took to removing the trailing arm out of the bushing pocket. At this point you could remove the drive shaft output flange and 4 sub-frame bolts and drop the entire rear suspension. I decided to take out each trailing arm to make the whole mess less heavy.

And this is what a blown RTAB looks like. It is not supposed to be broken free from it's bushing. Looks like the original "flanged" design that most likely came on the car. After having owned an m3 now for the better part of 4 years I tell anyone who just bought one to replace these right away. If you didn't buy from an enthusiast they're most likely toast and can be a major factor in poor handling.

Here I am excitedly showing how much play actually exists in these now defunct bushings.

With the rear trailing arms removed I set out to pull the hubs apart. This is no easy task since there is a huge dust shield in the way making any press work a bitch. I found a a video where a guy put a bearing separator behind the hub and uses the lugs to push the hub out from the trailing arm.

You can do this on the car as well if you're just doing wheel bearings. Problem was the separator wasn't thick enough or the bolts weren't long enough. I had to build up an area to press against to pull the hub off.

Now this method puts a lot of force on the threads of the hub and can strip your hub. If you don't have a press and want to pull the bearings with the trailing arm on the car this is really your best best. If you equally use 5 studs to remove the hub it will be less stress on your threads.

There is no way to NOT destroy the bearing. Removing the hub pulls the bearing apart.

And then you're left with this. The inner bearing race jammed up against the hub. Again without a press this is a bitch to get off. My buddy was wondering how to get these off without a press so I used the same method again. Apply the bearing separator and then turn the bolts through pushing the hub off the race.

Needless to say this took forever and looks pretty ghetto but it works. For the other side I used the same principles of force but just used a press instead. Life was much better and about 95% faster on the other side.

Alternatively shown here with a press, gripping the race tightly and propping it up on some steel blocks I was able to push the other side out with little swearing.

Before I got to that point I had to press the hub out from the trailing arm. I basically have the setup above this picture underneath the dust shield. Using a press is a combination of creativity, the hardware store aisle and experience. I understand now why shops charge what they do to press things. You need ALOT of special sized sleeves and press fittings. I would've spent more on those things alone vs just having a shop press them if I didn't have access to a bunch of scrap in the fab shop at work.

 Since the RTAB have those flanges on them, I had to grind them away to get a surface to press against.

The two control arm bushings came out easy enough with a square tall pipe beneath them. This is a 20 ton press from harbor freight by the way. Honestly, it works great. The wheel bearing as well as the bushings for the sub-frame and control arms also still had to be pressed out and I was just getting started. This is all I'm going to talk about with the press if you have any questions leave them in the comments below!