LF Clunking Noise

[BCS_ZHP]

So developed a noise this week, had to go into & out of a grass parking lot all week and could definitely hear a noise from my front end. Replaced the FCABs on Saturday, they were weak, but that didn't cure it completely. Gary (GSen80) assisted on the FCAB replacement, then we took it for a 4-wheel alignment. Asked that guy to check everything in the front end -- tire rods, ball joints, sway bar links, sway bar bushings -- all was fine. Next to an old friends shop, he too checked everything and couldn't find anything amiss but I still have the noise. And its not the front brakes, it makes this noise at slow speeds over any rough road or bumps.

So Gary & I deduced its definitely coming from only the left front corner, not the rear or the right front, we're positive on that bit of the dilemma. Gary suspects a bad LF strut but there's no signs of any leakage on that specific strut. I talked with Jon (AU2bahn) today and he postulated maybe the LF tophat has gone bad, we might be hearing the bad bearing up there binding and letting go.

I'm lost, has anyone had something like this before? Cheapest way to go is to order a couple of new tophats and try that to see if it cures the problem. And if its not the tophats, then I probably have to buy front struts to see if that cures the problem. But I'm torn between not dumping a lot of money into the stock suspension and doing something aftermarket like a cup kit. Any ideas???

Bruce

[danewilson77]

How old are strut mounts? Springs checked out?

Sent from Williamsburg, VA USA

[BCS_ZHP]

68K miles, all original, it rides tighter than the 40K mile conv. The springs appear to be fine but didn't remove. Going to need a spring compressor to really figure this out.

[danewilson77]

Hmmm...

Sent from Williamsburg, VA USA

[BCS_ZHP]

Dane - talked to the PO, he heard it intermittently too but could never get it to recur for a shop. Well, it's doing it all the time now but no one is sure what it is, they don't want to tell me something to replace and find out that was wrong. You can drive it on Friday and see if you have any idea. But may order top hats anyway to change those this weekend and see if that's the problem. I'm going to call Bimmerworld in the morning and talk with them about it since they sell top hats for only$40 per side.
Bruce

[Johnmadd]

Bruce, I think we have the same issue but different sides. Dane has suggested shock mount and I have yet to confirm but my other guess is motor mount.

[BCS_ZHP]

John,
I talked with Bimmerworld, the dealer, & 2 indys today about this noise -- the shock mount is strongly suspected. So I figure if that left front corner is going to come apart, then I'm going to replace everything including upper & lower spring pads plus all nuts, washers, etc. I ordered everything for both sides even though it appears only my left front is the culprit for now If this works, I should have the necessary parts on hand this weekend to do your right side if you want to try it.
Bruce

[Johnmadd]

I may take you up on that Bruce. We will have to see if it is the same sound.

You also have spring compressor?

[BCS_ZHP]

John,
I have access to a spring compressor, a coworker will lend me his. If I can get all the parts in time, I may use my old faithful mechanic friend to install it. He said book time is only 2 hours, and then I'm going to need an alignment anyway which he can also do because my alignment is jacked up. Took it to a local Indy for a 4-wheel alignment last Saturday after the FCAB replacement. Looked under there tonight and their young alignment guy used a monkey wrench on the tie-rod adjustment even though both sides accept an open end wrench. Also talked with Bimmerworld today cause it's drifting on the highway and he said it likely has toe-in set at zero or even slightly positive because a BMW should be toed slightly negative and never ever wander in the lane.
Bruce

[alexandre]

Please update this thread after the weekend... I'm having the exact same issue.

[Jesse M]

I can almost guarantee you that it is the shock mount. I had the same noise over tiny bumps and could hear the noise you described. I would replace them anyway. Mine were just old and the bearing failed.

[Hornung418]

Actually...this noise turned out to be a loose brake caliper slide pin.

[danewilson77]

Actually...this noise turned out to be a loose brake caliper slide pin.

And a combination of suspension related components.

Sent from Williamsburg, VA USA

[Hornung418]

FCABs mainly.

[Jesse M]

Actually...this noise turned out to be a loose brake caliper slide pin.

That's ... strange.. glad you found it.

[danewilson77]

That's ... strange.. glad you found it.

Not strange since recent brake work had been done.

[Jesse M]

Well, apparently I missed that.