Squealing from the front but maybe not the brakes...

[Friz]

Hi All,

My 2004 w203 gives me a squeal from the front drivers side when going through a gentle right hand bend. It doesn't happen when cold. But as it warms up I can hear it start. A quick touch of the brakes stops it but then it returns awhile later. If I continue on without touching the brakes it turns into an embarrassingly loud screech. But again, a quick touch of the brakes stops it. I originally though it was the front pads so I changed those. They needed it anyway. While down there I had a look at everything else and it looks good. Discs look fine and rotate freely. All the bushings and everything look fine too.

But the squeal still shows up. Not at motorway speeds but more on the backroads around 40-60 mph. And only in gentle right hand bends.

What should I be looking for? Ball joints? Wheel bearings?

Thanks.

 

[andymerc]

could be a brake caplier sticking were the pads unevenly worn when they were changed? does the right hand wheel feel warmer than the left after driving?

 

[SSBB]

Almost certainly a wheel bearing.
When your car is on a bend there are different forces acting on the wheels, they are being 'flexed' verticaly which puts lateral stresses on the bearings. When you touch the brakes, the car attempts to right itself, (which is why if you took your hands of the steering wheel it would turn back to its central position ) and relieves those stresses getting rid of the noise until the bearings settle again.

 

[SSBB]

Raise the car on a jack, hold the wheel (brakes off) at 12 O'clock and 6 O'clock and then simultaneously push and pull (gently). Rotate the wheel one quarter and repeat until a full revolution has been done. You should be able to feel any lateral (sideways) play. It does take a bit of experience to know what it feels like but worth trying yourself before taking to a dealer.

 

[Friz]

Raise the car on a jack, hold the wheel (brakes off) at 12 O'clock and 6 O'clock and then simultaneously push and pull (gently). Rotate the wheel one quarter and repeat until a full revolution has been done. You should be able to feel any lateral (sideways) play. It does take a bit of experience to know what it feels like but worth trying yourself before taking to a dealer.

Did that. no play at all either in the 12-6 or the 3-9 positions.

I just keep thinking maybe some bearing grease.

 

[Friz]

could be a brake caplier sticking were the pads unevenly worn when they were changed? does the right hand wheel feel warmer than the left after driving?

everything was even.

 

[lynall]

What no play at all what so ever? there should be a very small amount of play on the merc front bearings.



Lynall

 

[BlackC55]

do you have the sport pack brakes?

 

[Friz]

Nope. Standard brakes. And no. There is no play at all.

 

[Friz]

Oh wait. Just re-read SSBB's post. I didn't rotate the 1/4 turns. Just checked the 12-6 and the 3-9.

Makes sense though. I'll try that tonight.

 

[BlackC55]

It will be the pad retaing springs on the pad carrier causing your issue. They rub on the disc and make a very high pitched squeek.

 

[Friz]

It will be the pad retaing springs on the pad carrier causing your issue. They rub on the disc and make a very high pitched squeek.

That actually makes a hell of alot of sense. I can picture that happening...


How to correct?

 

[Friz]

Took that front wheel off again and had a look at the clips. top one was about half a centimeter right of center. Took both the top and bottom ones off and cleaned all the gunked up brake dust out of them, placed them back centered, and haven't heard the squeal since...

Happy days.