[1986Benzy]

I have a 1986 300E, there has been a subtle grinding / whirling noise that would appear to be coming from the front passenger wheel area, it is clearly correlated with the speed and rotation of the tire, that also stops whenever I put my foot on the break. (I swear it started after going over a particularly large pothole). I recently took the car to a shop, where they initially thought it was a bad wheel bearing but after looking at it simply tightened the shock. However, the noise still is persisting. My other thought is that a brake pad is possibly dis aligned but does anyone have an alternative suggestion / hypothesis?

Thanks,

 

[sbaert]

My initial guess would be bad ball joints and/or bearings. I would also seriously look at every single steering & suspension for wear & tear/failure.

 

[Kajtek1]

Noise stopping with braking makes it tricky.
I would lift the wheel and rotate it, listening if you can hear any noise this way.
Than I would put new brake pads and recheck the rotors.

 

[1986Benzy]

My initial guess would be bad ball joints and/or bearings. I would also seriously look at every single steering & suspension for wear & tear/failure.

yeah I actually had the shop take a look at the suspension and they seemed to think everything was in really good order. The car only has 95,000 miles on it although I realize just the length of its life generates substantial wear. Again I swear I can pinpoint when this noise started - after that wheel took a particular pothole hit / dip.

I also would add that while the volume of the noise does not increase with speed the frequency of it does, hence my belief that its something out of line or rubbing during the rotations

 

[sbaert]

Also be sure to check the ABS pickup sensor and wheel. Sometimes there is metallic build up on the sensor which can rub on the sensor wheel.

I'm thinking the ball joint took a fatal blow when it met the pothole and while the damage may not be visible, the now damaged ball joint might be rubbing slightly on the dust shield for the brake rotor.

 

[herr.benz]

I would agree that Its sounds like your ball bearing are shot. I had this issue in a chevy blazer...know this is a benz forum. But nonetheless check those bearing again. I would check the pads and rotors for roughness first though

 

[1986Benzy]

My knowledge of cars is extremely limited but would the ball bearing being damaged be consistent with the noise completely stopping while breaking?

 

[Kajtek1]

My knowledge of cars is extremely limited but would the ball bearing being damaged be consistent with the noise completely stopping while breaking?

Very likely not, nor the sensor rubbing would stop with braking, but with complicated suspension geometry lot of things can interfere with each other.
When shop mechanics gave up on finding the problem , it is not going to be easy.

 

[tuttebenne]

I like Kajtek's suggestion to lift the wheel and spin it slowly at first and faster if you don't hear the noise. This approach can get you close to the problem relatively easily.

Does this car have "Kleen Wheels" brake dust shields on it?

Also, have you checked the wheel to see if it had bent and now is running out?

 

[Kajtek1]

Also since this is likely pothole related - check the rims. I lost rim on Los Angeles pothole once, when car cut me off and I went braking on the shoulder. The pothole made almost 1" dent on the rim lip, although the tire hold the air and I noticed that 150 miles later.
Checking if the wheel is straight is not easy. Usually on lifted wheel, I put a block of wood on the driveway and observe the gap between the block and the edge of the tire while turning.
All the safety precautions apply, especially when you are checking the rear wheels and have to release parking brake.

 

[1986Benzy]

Very likely not, nor the sensor rubbing would stop with braking, but with complicated suspension geometry lot of things can interfere with each other.
When shop mechanics gave up on finding the problem , it is not going to be easy.

Well from what I was told they didn't give up, they just didnt see anything wrong, they said they drove it around and didn't notice anything except the loose shock. Unless your listening for it and going pretty slowly (under 20 mph) its pretty difficult to hear the noise

 

[Kajtek1]

I think the proper wording would be "they choose not to hear it"
This way, or the other you are on your own.