[Yzandrl]

Once again, I’m bringing a case before the learned colleagues on e90post for diagnosis. :-)

The patient and history: a 2006 330i with performance suspension and brakes that were installed in 2013 with all the M3 parts and has 74K miles but less than half on the new components. It has worked like a dream for two years. However, it has this noise that is getting worse now over the months.

The symptom: It is a light double clunk-clunk in the front that occurs occasionally when driving and turning at slow speeds or specifically EVERY time when…

• Leaving the car to rest for a while (an hour or so) on a ‘smooth surface’ such as parking garage.
• Starting the car
• Putting it into drive
• Let the foot off the brake going forward
• and turning left (this rewards you with a light knock/clunk, almost two movements combined to make one clunk-clunk noise, and then another lighter knock/clunk when the wheel returns to a straight position).

The kicker? I cannot reproduce it by just stopping again and starting and it won’t happen again until the next time I park it and leave it alone for an hour or two and repeat.

Things that have been tried to diagnosis it?

• We’ve put it up on a lift and used a pry bar to test all the ball joints, fittings, and more. (Everything is new/tight)
• Had an alignment done (all good)
• The stabilizer rubber and ends (tight, no play)
• The rack is solidly mounted (no play, tight, and has sufficient fluid, no leaks, nothing)
• The sub frame is snug (not loose)
• We’ve turned the wheels checking the tie rods (inner, outer, no play)
• We’ve checked the control arms, tension arms (solid, no play)
• We’ve moved the steering wheel left right (no play, solid, even a centimeter left or right transitions to both wheel visibly).
• Turning the steering wheel with engine on or off trying to make a noise (none is found while on the ground or unloaded on lift)

It is tight, silent, and everything is nearly new condition, fluid levels are fine, there is no play in the system and it doesn’t show up when driving normally minus the occasional slow turn surprise.

The dealership can’t find it and has ‘officially stated’ it is fine, normal, and safe to drive. They find that going further would be a waste of money (Admittedly, a fair answer). I still would really, really like to find out what the issue is and then decide IF it is worth fixing…but right now anything I do would be just throwing parts at it hoping to fix it which is a very poor choice on a nearly 10 year old car regardless of condition.

The only other potential point where the noise occurs is when moving slowly, and turning into my driveway (right hand turn) which has a ‘lip’ transition from the road to the driveway leaving both wheels at a slight different height (nearly 1 inch difference) and when turning the suspension is under a slightly increased load. However this is just a noise and not the ‘same’ as described above.

I’m stumped; any ideas of what I could check or test?

[justpete]

Originally Posted by Yzandrl

Once again, I’m bringing a case before the learned colleagues on e90post for diagnosis. :-)

The patient and history: a 2006 330i with performance suspension and brakes that were installed in 2013 with all the M3 parts and has 74K miles but less than half on the new components. It has worked like a dream for two years. However, it has this noise that is getting worse now over the months.

The symptom: It is a light double clunk-clunk in the front that occurs occasionally when driving and turning at slow speeds or specifically EVERY time when…

• Leaving the car to rest for a while (an hour or so) on a ‘smooth surface’ such as parking garage.
• Starting the car
• Putting it into drive
• Let the foot off the brake going forward
• and turning left (this rewards you with a light knock/clunk, almost two movements combined to make one clunk-clunk noise, and then another lighter knock/clunk when the wheel returns to a straight position).

The kicker? I cannot reproduce it by just stopping again and starting and it won’t happen again until the next time I park it and leave it alone for an hour or two and repeat.

Things that have been tried to diagnosis it?

• We’ve put it up on a lift and used a pry bar to test all the ball joints, fittings, and more. (Everything is new/tight)
• Had an alignment done (all good)
• The stabilizer rubber and ends (tight, no play)
• The rack is solidly mounted (no play, tight, and has sufficient fluid, no leaks, nothing)
• The sub frame is snug (not loose)
• We’ve turned the wheels checking the tie rods (inner, outer, no play)
• We’ve checked the control arms, tension arms (solid, no play)
• We’ve moved the steering wheel left right (no play, solid, even a centimeter left or right transitions to both wheel visibly).
• Turning the steering wheel with engine on or off trying to make a noise (none is found while on the ground or unloaded on lift)

It is tight, silent, and everything is nearly new condition, fluid levels are fine, there is no play in the system and it doesn’t show up when driving normally minus the occasional slow turn surprise.

The dealership can’t find it and has ‘officially stated’ it is fine, normal, and safe to drive. They find that going further would be a waste of money (Admittedly, a fair answer). I still would really, really like to find out what the issue is and then decide IF it is worth fixing…but right now anything I do would be just throwing parts at it hoping to fix it which is a very poor choice on a nearly 10 year old car regardless of condition.

The only other potential point where the noise occurs is when moving slowly, and turning into my driveway (right hand turn) which has a ‘lip’ transition from the road to the driveway leaving both wheels at a slight different height (nearly 1 inch difference) and when turning the suspension is under a slightly increased load. However this is just a noise and not the ‘same’ as described above.

I’m stumped; any ideas of what I could check or test?

Wheel bearings? Upper strut mount? Or is the spring moving against the perch?

[mob17]

I had similar noises and it was the top mount. But i would have thought if it were that simple your garage/dealer would have diagnosed it.

By the way my BMW dealership said my front top mounts dont fit my "aftermarket coilovers", which is bullshit as they are Ohlins and one was just siezed.

Take it to a specialist suspension indy?

[vwetish]

I would say strut mount going bad.

[Yzandrl]

I think that is my next item to check. I had it on a lift yesterday and went through the entire suspension components taking a few hours to really see it all. I finally gave up and starting thinking maybe it is from wear in a way that isn't loose but moves weird with a notch, catch, or tension point that breaks free with that noise after exerting pressure. I then started playing games by putting one front tire on at a time, lowering it to compress the one wheel and steering left and right while the other was uncompressed just to see what noise it would make. I tried to see if the spring was moving or binding but there is no wear on the rubber and they didn't move or anything out of place. I thought it might even be wheel bearing or brake related as I was running out of ideas so I pulled the brakes off and had some rust on the guide pins so I wire brushed it off, made sure the clip was good, and cleaned them up nice (the bearings were fine too). So, I have nice clean brakes at least…
So for checking this top hat/strut mount...what is a good way to go about it? I’ve had bearing and strut mount play before and it was always a rattle that I could find on my local cobblestone road. I don’t think it is loose enough to diagnose it by wiggling, lifting, pulling fenders or driving cobblestones for that rattle noise. How can I do this? Do I compress the spring, zip tie it, lift it up and then check for play? Should I remove the nut and check the washer stack? If I mark it carefully the position and remove the assembly, will I need an alignment afterwards? (note: I just had an alignment done with the switching to summer tires and after they ‘looked for my noise’ so I would think they would have found it). Any other tests? After that, what is left? The damper only with internal noise?

[Yzandrl]

I think I found the problem. I zip tied the springs and checked for play. There is none and the bearing isn't loose, but it doesn't turn smooth, it is stuck until enough pressure is there from the wheel turn then the bearing turns with a 'dunk' noise as the tension is released and bearing turns into position matching the piston rod. I only found it only by putting it back on the ground, holding the top nut with my fingers and having someone turn the wheel and voilà they made the noise and I felt the nut ‘jump’. It wouldn't replicate while in on the lift. I hope that the damper internal seal is not shot now from rotation like this. I plan to swap them out in the next few days. I figure new since I'm in there and they are a few years old it is better to replace than to try to remove, degrease them and repack with a quality bicycle bearing lube and re-seal since they may be damaged and not just dirty.

[ajsalida]

If you install the two washers under the strut mount and on top of the spring perch wrong order or the curved one wrong side up, you'll eventually get this problem. Of course the bearing itself might be bad.

[vwetish]

Originally Posted by ajsalida

If you install the two washers under the strut mount and on top of the spring perch wrong order or the curved one wrong side up, you'll eventually get this problem. Of course the bearing itself might be bad.

is only one washer that needs to be with convex side up.
the other thing is not a washer but a dust/debris shield that you can go with out (some models don't even have it)

[ajsalida]

Originally Posted by vwetish

is only one washer that needs to be with convex side up.
the other thing is not a washer but a dust/debris shield that you can go with out (some models don't even have it)

Yes, correct, only one convex washer. The other is a dust seal under the mount but it looks like a washer and people screw it up all the time. I would not recommend leaving it out.

[Yzandrl]

I was able to determine and remove the noise finally when I took it apart and replaced the mounts and some extras. With the intent to be extra careful as I didn’t want to have to arrange a ride to the dealership when I broke, or found something overly worn, I ordered all the washers, bolts, and replaced all the spring rubbers and dust cover since they were cheap and rubber dries out.

The issue was two-parts. One of the garages did not install the plastic caps on the top allowing dirt in which allowed the bearing to fail pre-maturely; I should have figured that out so I’ll take the hit. The primary cause was the washer with one side flat and one side convex was missing completely allowing the spring plate to rub directly on the strut mount. The spring seat had rub marks in it and I replaced that and all the rubber items on the damper. Since it was replaced, it is fixed and even turns easier than before since the friction in the bearing and the spring seat is gone.

One question, when I finished putting the strut mounts in, one had no play (wobble) but the second one has a slight bearing play in it when I move it back and forth. Is that acceptable? I don’t hear any noise from it.

Sadly, this will join my growing list of stories from garage mistakes/failures. I know they are forced to work aggressive schedules and cut corners (like never using a torque wrench, only the air wrench) but this one really has pissed. Most of these are dealerships too because of my location independents are difficult to find that can even change a battery properly without a reset tool for example. On the good side I’ve become very proficient and have a very large and ever growing suite of tools.