E34 touring front suspension clunk

[Nick_S]

I'm trying to figure out what is clunking in my front end. Have receipts from previous owner that nearly all bushings are new within the last 25k. I put new bilstein sports with bav-auto springs and new shock mounts last summer. When I go over bumps or brake it clunks. Took a wheel off tonight and have isolated it down to forward and back movement. The clunk seems to be resonating from thr shock mount but I'm not convinced that's the issue as the movement is towards the bottom of the strut housing. I'm quite the noob at suspension geometry so I'm trying to figure this out. Any help is appreciated.

[AndrewBird]

The gland nut holding the strut into the tube might be loose, causing the strut to move around. Bad upper mounts will also clunk, ball joints, etc.

Put the car in the air, grab each side of the tire and shake it back and forth. Than grab the top and bottom and do he same. When the clunk occurs will help narrow down what is clunking.

[Nick_S]

I had it up on a jack with the wheel off. I can pretty definitively narrow it down to back and fourth movement. While moving it I was feeling around the upper part of the strut and couldn't really feel much moving. Seems to be mostly isolated towards the bottom. I'm guessing it's from worn control arm bushings, hoping it's not the ball joints and will replace with some poly bushings. It was freezing and dark so I couldn't get a real good look. Will be able to get it on a lift this weekend.

[mottati]

sounds like thrust arm bushing. If they were poor quality or not installed properly (i.e. torqued down while car was in the air rather than with suspension under load) they could definitely fail in 25k miles.

[Nick_S]

sounds like thrust arm bushing. If they were poor quality or not installed properly (i.e. torqued down while car was in the air rather than with suspension under load) they could definitely fail in 25k miles.

You're the second person who has mentioned this. To clarify, the thrust arm is same as the upper control arm?

[MikeDE]

Nick,

I replaced my beatdown original struts/springs/strut bearings/thrust arm bushings yesterday with Lowtec sports/HR 45-10mm/Sachs/E34 M5 bushings respectively, and no more clunk, which occured mainly in low-speed situations.

I would definitely do the thrust-arm bushings first, have a good size/long tie-rod/ball-joint puller handy if you don't want to pull the strut assy. A hammer worked on mine as my puller was too small & the assemblies were already out. The E34 M5/540i bushings are a great deal, they cost me €42($56) from the dealer. They're higher durometer rubber than the standard units, and are cheap enough to replace every other year. Just make sure you tighten them down AT RIDE HEIGHT. I did mine, drove it about 30 seconds so it settled, then drove it up on ramps to tighten them down.

Good Luck....edit: yeah it's the upper arm that head towards the rear of the car.

[Nick_S]

Good to know! The low speed clunk is exactly what I'm getting. Opinions on poly vs. OEM bushing? I'd like to get a few more years out of the car (just hit 260K) so if I didn't have to mess with these again that would be ideal.

[m735is]

On both my e34 and e32, I had a clunk when braking and going over slow speed bumps, like turning into a parking lot that has a trimmed down curb. Ultimately it turned out to be the lower control arm ball joint. After a lot of replacement parts and messing around, I could only get the ball joint to show signs of looseness with the strut tube detached from the support arm. All other scenarios kept just enough tension on the joint and it felt tight.
Although upper arm bushings are always a good place to start.

[Nick_S]

On both my e34 and e32, I had a clunk when braking and going over slow speed bumps, like turning into a parking lot that has a trimmed down curb. Ultimately it turned out to be the lower control arm ball joint. After a lot of replacement parts and messing around, I could only get the ball joint to show signs of looseness with the strut tube detached from the support arm. All other scenarios kept just enough tension on the joint and it felt tight.
Although upper arm bushings are always a good place to start.

exact thing I'm experiencing. Unfortunately it's been too damn frigid to bother with it. Although strangely it does it less in the cold weather?

[CorvallisBMW]

Make sure that you get the 750i thrust arms, they're more robust than the standard e34 ones. And like everyone said, be sure that you don't tighten them down until the suspension is under load. They are very susceptible to incorrect pre-load and failure to do it correctly will definitely cause failure within 25k miles.

Here's a photo of the 750i vs stock e34 bushings side-by-side:

[slammin.e28]

Buy these, put them in, enjoy car.

http://mooseheadengineering.com/#!/~...126&id=6647004

No e28/e34 should be without them.

[mooseheadm5]

E32 arms are not the same length as E34, I wouldn't recommend them. Meyle HD arms come with HD bushings like the ones in the pic above, though.

[Nick_S]

Buy these, put them in, enjoy car.

http://mooseheadengineering.com/#!/~/product/category=1512126&id=6647004

No e28/e34 should be without them.

Damn, those look awesome. Thanks for the link. Soon as the weather breaks above 20 degree's I'll get on this.