03-14-2010, 01:52 AM
Officially Welcomed to the 'Fest
Join Date: Jul 2008
Mein Auto: 528i
Rebuilding the front suspension, with pics
1999 BMW 528iT, 120K miles. Front end is original.
Used OEM or better for the overhaul. Struts, Thrust arms, control arms, tie rods, sway bar links and all the misc accessories.
At the last minute decided to do the wheel bearings and what a good decision that turned out to be.
I wish I could take credit for this but let's just say I got a bit of capable help with it.
I won't duplicate the already excellent "Front Suspension DIY" but here are a few additional items to point out.
Here are the thrust arm and control arm installed, the Beilstein HD strut is visible in its unmistakable yellow color.
The new wheel bearing installed.
I tried to use an air tool with the plate out and laying on the floor and 4 bolts visible in the back, but my compressor was flaky so ended up putting it in a vice and undoing the 4 bolts in the back. The other method is to unbolt the wheel bearing with the plate installed in the car, that's another good idea, just a bit slower.
My old wheel bearings were on the verge of wearing out, judging by the slight noise that came out of them. The fact is, the wheel bearings are impossible to remove without removing the strut, more evidence of engineering genius. Since I had the whole thing out, I thought might as well swap the wheel bearings too.
One of the most troublesome elements in this whole saga was the passenger's side sway bar bushing, difficult to remove the old one and nearly impossible to put in the new one, very little clearance. To be specific, the bushing itself went in OK but the bracket that goes over it was the problem, it just wouldn't go in. The trick was to loosen the driver's side sway bar bushing bolts, giving it some room, then the impossible becomes just difficult. Stupid design, needs just a few inches of clearance.
The driver's side sway bar bushing was OTOH a piece of cake, just came out, since there is no exhaust in the way like on passenger's side.
Let's review this pile of the dead bones.
First, the OEM struts were completely, catastrophically dead, all the oil leaked, could be compressed by hand. The "bounce test" suggested they were shot.
The thrust arms, control arms and tie rods were all in various stages of decomposition. The bushings cracked, one tie rod pretty loose.
The wheel bearings were either already worn out or just about to be. They, like the rest of the components had 120K miles on them so they were right on time.
The bearings for the struts were in bad shape. One was completely gone.
The sway bar bushing were obviously worn but not destroyed.
The only piece in the whole suspension that was "OK" and could probably be reused, especially considering it's the easiest component to replace, was the sway bar links. They were put in some 40K miles prior which explains why they weren't shot.
One casualty of this whole engagement was the unrelated air pump vent tube. During the jacking up phase, it just decided to crack its tired, brittle 10 year old self. A quick trip to the dealership and 35 Federal Reserve Notes later, resulted in a new one installed. I know I could have used regular hose but what the hey. Basically a POS is a POS and the new tube doesn't seem to be redesigned.
To summarize, the handling has improved, which is obvious in that the steering wheel is greatly responsive to the slightest move. Basically, it handles like a new car, precise. I haven't yet tested it on curvy roads but I expect less body roll.
1999 BMW 528iT. Station wagons are back.
Last edited by etc; 03-14-2010 at 03:32 AM.