jahummer

Had brakes changed by dealer couple thousand miles ago on MY00 w220, brakes worked great and quietly. Recently had rain every day for about a week and drove through flooded streets (6" of water or so). Now that the rain is over and the roads are dry, my brakes are squealing loudly every time I use them.

Any idea why and what the fix would be? Thanks for your help.

GDawgC220

my guess is some rust has formed from the big puddles? have you tried to wash the wheels with a good wheel cleaner to get rid of what may be on the brakes? also, how dirty are the wheels? brake dust does contribute to squeeking also.

try this, take some wheel cleaner (i recommend Eagle one A to Z, orange colored) spray the wheels and hose them off GOOD. Then drive around to see if there's any difference

jahummer

They are pretty dirty considering there hasn't been a dry day in 2 weeks (so no car washing). I'll try that and let you know what happens. Thanks!

saturnstyl

Question: Did they change the pads only, or the pads and rotors? I don't like replacing pads without rotors anymore, creates too many noise problems. Mercedes rotors are soft, and the grooved surfaces they have when worn are bad for making noise with new pads.

jahummer

Everything was changed, pads, sensors, shims, anti-squeal paste & rotors.

saturnstyl

Well no matter then! Parts warranty!!! Take it back and they will make it right. Maybe you got some really old brake pads, I think they have been changing the formulation of the matierial to help eliminate noises. Could also be that a shim slipped out during assembly, it happens sometimes.

jahummer

OKay, I cleaned the wheels and brakes, but the squealing has not gone away. So I stopped by the dealer today and they said because of all of the humidity, I need to do more braking to get rid of the squealing. Well I have never had this problem before so I am still a bit skeptical.

saturnstyl

It is quite prevalent on the 129 cars (SL) that the brakes squeal under light application. Driving around the block and making several hard stops temporarily fixes it. Its not a problem on the 220 cars though. I live in an area of almost constant 100% humidity and its not an issue. I call BS. Let it ride for a week or so and if it doesn't clear up take it back.

Kestas

Perhaps the antisqueal paste got washed away and needs to be replenished.

jahummer

Does that really happen? I've never had problems with squealing brakes before. It doesn't squeal under heavy braking, only light braking.

Kestas

A lot of effort has gone into manufacturing disc brake systems that don't squeal. Squeal is the #1 reason for return visit to a mechanic after brake work.

A little background. Squeal manifests itself because of the tiny bit of shimmy in the rotor vibrates the brake pad backing against the metal parts. Antisqueal paste is supposed to lubricate or dampen this rubbing to get rid of the noise.

If your brakes have squeal now, your rotors have a bit of vibration. It is concieveable that this vibration under water washed away the antisqueal paste. MB uses what is essentially copper-based antisieze compound for antisqueal. A lot of aftermarket brakes are serviced with a (blue) goop that hardens, but stays plastic. It makes sense to me that the MB (copper-based antisieze) compound is easier to wash off underwater than the goop. If driving through deep water is an unavoidable habit, then you may want to switch to the blue goop for antisqueal on your brakes.

I can only guess that heavy braking perhaps prevents the vibration that gives you the noise you're hearing.

jahummer

Okay, had my pads checked out. Apparently the squealing is coming from the rear and is due to the the fact that the Jurid brand pads are metallic, at least according to the tech. He said that the jurids have the best stopping power and lowest pad wear and dust but are noisy.

mleskovar

No passenger car pads are supposed to constantly squeel. True, sometimes the squeel goes away with time, but not usually. My guess is the lubrication (paste). Since I started using ceramic paste my squeeling has stopped. I've put new pads on, had them squeel, immediately took them off/cleaned/new paste...and the noise stopped.