the head

OK I've been trying to figure this out for a while and am at a dead end. I have noise that sounds like a metal creak/squeak that comes with each rotation of the left front wheel (driver's side). There is nothing in the tire like a nail or rock. It was there prior to the dealer replacing the torque arm bushing under warranty. I have removed the pads and lubed the sliding points with CRC brake grease as appropriate and also used the red brake anti-squeal on the back of the pads where the caliper pistons interface with them. I have even gone so far as to remove the bolts that hold the rotor to the hub (2-piece rotor), lightly sanded the "shiny" spots on the clips/retaining hardware, and placed a bare minimum of brake grease on them. I have checked the bearings and they are fine, even repacked the outer bearing. I made sure the wheel speed sensor is not rubbing, nor the wheel lug bolts.
The noise appears after a few blocks of driving and then does not go away.
The rotors do have a lip from wear (40k miles, I'm guessing these are the original rotors). Pads are in great shape - I think the dealer replaced them a year ago when I bought the car. Not that long ago when I took the car in for the rear wiggle, they did try troubleshooting this as well. One of the steps they claim to have done that I have not tried is changing the wheel to the passenger side. They said the noise stayed on the left side. They stopped short of replacing the brakes (I asked them to stop when anything not covered by warranty would be replaced). But since the noise seems to be with each rotation of the wheel, I'm guessing this is just the next logical step.
About the only thing I haven't tried short of replacing it is to remove the rotor from the hub and wire brush the rust off the hub and see if that is it.
I do not have wear sensors so those are not a factor.
Any ideas?

alx

may be a dumb suggestion, but did you make sure your tin shield is not bent and touching the rotor?

the head

Not dumb at all. I did check prior and there are no interference issues with it on the rotor or the caliper.

the head

OK managed to get the rotor off of the hub and cleaned the rust off so the rotor slides on and off easily. Checked for rub spots behind the rotor and didn't see anything. Buttoned it all up and then did something different. I put the wheel on and then started spinning things, pressing on the tire and trying to replicate the sound and happened to notice a big flat spot on the tire. Previously had just looked at the wheel to make sure it was true on runout and not bent along the circumference but didn't check the tire. I drove it slowly and the creak corresponds with a section just in front of the flat spot. I'm now thinking it's the tire and apparently the dealer didn't swap wheels as they said (well, maybe - I have no real idea). Fortunately enough, I have a spare set of front tires that I can put on and see if it goes away.

alx

a creaking tire (rim???) would be something i would like to see. your car is now officially possessed in my book

the head

Well I can say it wasn't the tires. New shoes up front - still there. I guess it's the brakes so that's next. There goes the Christmas bonus.

Maverick1975

Are you absolutely 100% sure it's emanating from the wheels. Could this squeak not be the engine mounts? My ML63 had a squeak like this and I thought it was suspension related but it was work engine mounts (580hp will do that!) Just a thought

the head

I think so. I can drive up and down my driveway and it's at the same point in the rotation of the wheel. I can mark it with a grease pencil and it's in the same spot (I mark it at the contact point with the ground). The brake rotor is warped a bit, but I don't feel anything in the pedal. I'm not sure if it's due to the semi-floating design of the rotor or what. I'm about to send one off for measuring to see if I can just have the rotor made and then just re-use the rotor hub.

the head

Figured it out - FINALLY!

The bolts that hold the rim together around the outer circumference were loose. I found it when I took the wheel off again today to keep looking for this noise and the wheel fell over after removing it and it made a metallic "clang" sound. So after bouncing it on the ground a few times I could lean on the 'spokes' on the wheel and feel it move on the outer bead of the rim. I didn't have a 12-point bit to tighten them but the 6-point hex bit was enough to get a bite and at least snug them. I did check one of these earlier when troubleshooting and it was tight - should have checked several. It seemed that a few that were tight (about 3-4) and then were tight 180 degrees on the other side of the wheel as well. The loose bolts were between the two small groups of tight bolts. None were so loose that you could visibly see them backed out. However, there were a few that took a full turn to tighten. Took it for a drive and it's stone cold quiet. And just ordered a 6mm triple-square bit so I can tighten them correctly without stripping out the bolt head.

WHTEVO

A cheap easy fix is always a good one

Aaron

AMGSport

Kinda scary your two piece rims could've seperated while driving...yikes!

EXECMALIBU

The SL65 wheels have the (18) 8mm bolts that are 12 point and are very light possibly made of Titanium... The bolts are Lock-Tited using permanent Lock-Tite. If someone took the bolts out to straighten or chrome the wheel then they or the rim might be stripped...

Make absolutely sure the 18 bolts are Lock-Tited and are Gorilla tight... If any of them are stripped then I would not use the wheel on a 4500lb car...

abiazis

I have the same squeak that has been driving me nuts.........did all the brake stuff also, etc........I'll check bolts on the rim.........where did you order the 6mm triple square bit?

Thanks for this write-up and bit information in advance........

the head

As mentioned above, it is actually a 8mm 'triple square'. I picked up a 6mm off Ebay, but then found a set for a 6, 8, 10, and 12mm at Auto Zone.

I think the reason was an off-track excursion. It started doing it shortly after that. I torqued them to 12 ft-lb since a "good" wheel bolt on another rim started to spin at about 13 ft-lb. I turned it just enough to get it to move.