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etc 03-14-2010 01:52 AM

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.

helpmyfive 03-14-2010 06:14 AM

What cost of all the parts? Time?

cn90 03-14-2010 07:09 AM


Originally Posted by helpmyfive (Post 5015892)
What cost of all the parts? Time?

Everything from procedure, PNs, to prices is here. I highly recommend, good people to do business with:

Time: about 8-10h depending on the experience.
(The only hiccup is the passenger's side swaybar bushing as I mentioned in the DIY, it took me 1.5h just for that stupid thing).
Very doable.

My car runs really solid now.

I am doing the REAR suspension in a few months using mmm635's DIY and will post a DIY later.

Fudman 03-14-2010 08:08 AM

Nice! Gotta ask how you torqued up the thrust and control arm bushing bolts. I replaced my control arms, weighted the car, turned the wheels lock to lock to access the bushing bolts and torqued them. This caused my steering wheel to be out of alignment. :cry: Not a huge problem, more annoying than anything. I have since redone this torquing procedure several times but the steering wheel is still out of alignment. The last time, I loosened up the bushing bolts, drove the car slowly, turning the wheel lock to lock to hopefully undo what I did. I then straightened the wheels, jacked up the car onto wheel pads I built of 2x10s, weighted the car and retorqued the bolts using new nuts. It's still off line. :mad: Is there a proper way to torque these bolts or should I just have an alignment done? :dunno: I'm gonna do my thrust arms and struts in a few weeks so I'm planning to have an alignment done anyway. Just wondering if you experienced anything like this.

cn90 03-14-2010 08:15 AM

Fudman, you did everything right, torque the nuts with car on the ground/weight.
Yes, you need alignment.

etc, I sent my old parts to a local metal scrapyard.
I keep 1 old thrust arm for target practice (tapping new bolts into aluminum!).

Hooray! 03-14-2010 08:19 AM

Good pics. The seller I purchased my car from had new OEM thrust arms installed (look like yours) with the OEM rubber bushings. I later read about solid bushings as an option (Bav Auto and others have them), did you consider these? I'm told our OEM thrust arm bushings will be toast in 60k just like the originals where the solid type have a longer life, how long did your first set last. Also, how do you like your new struts? Those are what I'm considering putting in as well, heard nothing but good reviews on them. Nice to have a tight front end again isn't it?

cn90 03-14-2010 08:48 AM


Originally Posted by Hooray! (Post 5016096)
.... I later read about solid bushings as an option (Bav Auto and others have them), did you consider these?

I as well the OP (etc) uses Thrust Arm (which is itself Lemforder), where the factory Boge bushing (liquid-filled) is replaced with Meyle HD Bushing.
What you see in the pics above the Meyle HD Bushing pressed in there.

Mark@EAC 03-14-2010 09:36 AM

well done! A complete front overhaul is a bit of work but the rewards are well worth it.

Jared has made up lists of the most commonly replaced suspension items for e39s, you can bookmark them for later reference. they are helpful to show you what parts are wear items and current pricing of the parts.

6 cylinder e39s:

540i e39s:

etc 03-14-2010 02:08 PM

To clarify, I got major help on this project from another dedicated forum member, half an hour from me. I did my share of the job but I wasn't the brains in this overhaul.

However, my confidence level has risen tremendously, if I have to do this again, I think I could probably do it alone. A great learning experience.

To reiterate, it's mostly time consuming but there are a few rough spots you have to watch for that can really slow you down. Like making sure the Strut spring fits nicely in the rubber gasket and does not rub against the metal. I think a hour was lost right there trying to seat it right. And another hour was lost fitting the passenger side sway bar bushing due to the idiotic design with no clearance.
That and an hour was lost trying to get the compressor to work right, to no avail and resorting to hand tools.

etc 03-14-2010 02:12 PM


Originally Posted by helpmyfive (Post 5015892)
What cost of all the parts? Time?

Just the parts where right around 1600 FRNs.

That includes the somewhat optional wheel bearings. If you have to overhaul the front end, you should probably overhaul the wheel bearings while you are at it, since (1) they are probably close to being shot and (2), they are super easy to do with the struts out.

etc 03-14-2010 02:18 PM


Originally Posted by cn90 (Post 5015959)

My car runs really solid now.

I am doing the REAR suspension in a few months using mmm635's DIY and will post a DIY later.

Yes, that's what I need. I have downtime planned in April or May when the weather is nice. My rear suspension is completely shot.

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