front end clunk when going over bumps

[krystar]

i got a clunk i'm trying to hunt down. pretty much only happens under 30mph. it's on the front passenger side. in the morning when cold like sub 20, it gets worse. however after driving a bit, it subsides a little. when sitting in passenger seat, my wife says she feels it in both feet. it feels like it's under the car, not the strut top mount. it sounds like....solid metal hitting solid metal. however occasionally it will repeatedly clunk with the right bump or speed. it only happens if passenger wheel hits a bump. no amount of bump on the driver side wheel makes the noise.

so far i've replaced:

entire LCA (new balljoints)
entire tie rod assembly
LCAB
sway bar endlinks
used strut
regreased strut mount



possible suspects?
engine mount?
tranny mount?




97 328 convertible.

[Luccia at Pelican Parts]

I would have guessed sway bar end links... Have you check the sway bar bushings? Since your wife says she feels it under the vehicle, I'd check there first. You'll want to check them for play. If they look like they need to be replaced, I'd suggest Powerflex as they'll last much longer than OEM replacement bushings.

1997 BMW 328i Base Convertible - Suspension Upgrades & Performance - Page 7

Also, while you're diagnosing this issue, just be sure to check the condition of your strut mounts. I know you greased them, but if it looks like the rubber is starting to separate from the inner metal sleeve it could cause an issue. Check over any and all bushings. Let me know what you find.

[krystar]

i'm able to induce a faint clunk very similar if i do a hard right jerk on steering. it happens on the return stroke of the suspension. hard left jerk has no clunk.

[krystar]

you mean the sway bar middle bushings? i think checked those already but will again. just disconnect endlinks and wiggle?

[Luccia at Pelican Parts]

The bushing that the yellow arrow is pointing at. We have info on them here about half way down in the body of text: BMW E30/E36 Front Suspension Overhaul | 3-Series (1983-1999) | Pelican Parts DIY Maitenance Article It will be fairly noticeable if they looked worn/damaged or torn. You can attempt to jiggle them inside the bracket and see if there is play. If there is movement/play it could definitely cause a clunk and make you feel something under the vehicle.



I'd also suggest you get under the vehicle while it's on jacks. Possibly have someone move the steering from side to side - somewhat aggressively. Jiggle things under there and see if you can recreate the clunk.

[krystar]

just checked. sway bushings are fine.

and just for good measure i removed the sway bar entirely and went for a drive. clunk still there.

[Luccia at Pelican Parts]

Ok, removing the sway bar was a good idea and that illuminates it from the process. I'd get under the vehicle and jiggle things around. Take a rubber mallet to things and knock on components to see if you can replicate it.

Another idea, Casey might have some additional input for you. The suspension overhaul article I posted above, click it. Scroll to the bottom of the comment box and leave a detailed comment, including everything you've checked/replaced. Casey will reply with his input on what it potentially could be as well.