Being driven mildly insane by suspension noise (BMW E39 content)

OK, I'm pretty much out of ideas here. Car in question is a 2001 BMW 525i, E39 body. In the last 10k miles or so, I have replaced essentially the entire suspension; in the front left, where the noise is, that means both control arms, sway bar end links, and struts (with mounts). I have also done the brake pads and rotors, the wheel bearings, and the tie rods, and had the car aligned in that time (alignment was just done).

Close inspection shows nothing loose, worn, or out of place.

The noise manifests itself is several ways (it is certainly possible I'm dealing with more than one cause here, but the absence of visible problems makes me think it's probably just one):

• A distinct single click will be heard when coming to a stop or accelerating from a stop, as if something is shifting as weight is transferred fore and aft.

• The same click will be heard going over sharp bumps at lower speeds; it is not apparent at highway speeds. If I had to guess I'd say it is occurring on the upward travel of the suspension rather than the rebound.

• When turning left, that is to say transferring weight off the left front wheel, a creaking will be heard, especially at slow speeds and sharp turn angles.

• The noise occurs fairly consistently, though not always. When the car is cold the noises seem to be more noticeable, though not greatly so.

• (The car also has a front-end shimmy at highway speeds, but I believe this is wheel balance-related rather than a symptom of the suspension issue.)

I've gone over it several times and I just can't figure out where the noise is coming from. Any thoughts would be appreciated.

How long has the noise been occurring? What wheels are on the car? Any chance that this is hubcentric issue with your wheel?

OE BBS Style 5s, same wheels that have been on the car since it left the factory. Hubs are relatively new (comes with the wheel bearing assembly) and clean, and the lug bolts are in fine shape and properly torqued. No sign that this is wheel-related.

Hard to say exactly how long it's been going on. I had a rear suspension issue that was overwhelming lesser noises for a while; now that it's fixed and the car properly aligned, I think I'm discovering other noises that had previously been masked.

With all you've replaced, any remaining creaking and clicking sounds like some broken spotwelds somewhere on the chassis.. This is going to be really hard to track down unless there is a common bad weld on the E39 that you can find out about.

Have someone drive your car around a parking lot at low speed, switching from forward to reverse, braking, turning full lock, etc, while you walk along with the car. If you can hear it from outside you just might be able to track it down.

Were the front wheel bearings replaced after you started hearing the noise?

I had a clunk drive me crazy on the mercedes. I guess one of the rear springs is sagging so I have to spray down the spring rubber top mount with silicone lube every couple of monthes to quite it down. Another weird problem I had was a clicking sound, what the hell is that clicking sound. Mercedes used a radio noise suppression spring in the front wheel bearing retainer nut. The copper spring grounds the bearing to the bearing cup to suppress radio interference from the bearing. The spring had broken and would periodically contact the front bearing and make a clicking sound.

What type of suspension does the BMtrouble you have?

The suspension is a relatively conventional strut arrangement similar to what the various 5-series chassis have used since the beginning. Two arms locate the wheel; BMW refers to these as the thrust arm and the control arm. Both are mounted to the aluminum subframe via large bushings, and to the steering knuckle via integral ball joints. Steering is a conventional rack and pinion.

The wheel bearings were replaced as preventive maintenance when I did the struts. As noted, I had some other noises that were likely masking this one, so I'm not entirely certain how long it's been present.

I had considered that it could be one of the spring pads (they were in good shape so I reused them) or possibly the sway bar bushings (the only thing left that I haven't changed). Either of these could account for the creaking, though I don't know about the clicking. Looking at them again today shows no signs of degradation or dislocation, however.

It could end up being something ridiculously difficult to track down, but I'm hoping that some new eyes on the problem(s) may reveal something obvious I've overlooked.

Look at #3 here http://www.realoem.com/bmw/showparts.do?model=DT53&mospid=47587&btnr=34_1121&hg=34&fg=05

You may want to lubricate it with a grease formulated for brake shims.