1992 500E brake noise... - PeachParts Mercedes-Benz Forum

blackmercedes · #1 04-21-2004, 04:18 PM

My cousin has a 1992 500E. She bought the car about 35,000km's ago (around 20Kmiles) and had it gone through with great detail. Included was brand new brakes on all four corners, discs and pads included.

Today, I was giving her a hand with an oil change (she bought a LiquidVac and I helped...) and when she was driving into my garage, the brakes made a HORRID grinding noise. I jacked the car and took off all four wheels, finding all pads (inside too...) in top shape and the discs looked good too. Didn't measure for run out, but they have no "lipping."

I hosed them off, hoping to get rid of dust. Still noisy.

Stumped. Should she be worried? I know MB's brakes are noisy, but these are LOUD!

BTW, I drove the car and the brakes work GREAT!

G-Benz · #2 04-21-2004, 05:33 PM

Different pad compounds do different things...consider now that asbestos pads are history (healthwise), most pads are metallic or some form of semi-metallic material. So there are more complaints about brake squeal nowadays than ever before!

And why not? Hot metal against really hot metal!

Fortunately there is a cure. For our cars, two things are the culprit...slight pad movement against the disc and/or calipers, and warped rotors.

The first symptom is easiest to fix. Get some brake paste (or brake grease, or brake spray) at the local auto parts store...different names for products that do the same thing.

Remove the pads and apply the product on the brake pad backsides (the side that contacts the calipers, not the disc). Reinstall the pads.

I've used paste before with good results, but this time I tried the spray as an experiment since I did my W124 front pads this weekend...so far no squeal!

If your rotors are warped, it may contribute to the noise...and btw, there isn't much factory tolerance for turning rotors, so replacement is the norm...fortunately, they are fairly inexpensive.

The rule of thumb here is to replace rotors once for every two to three brake pad jobs you do.

Now I hafta do the ML pads this weekend...

Ali Al-Chalabi · #3 04-21-2004, 06:42 PM

The early production run 500Es used a Brembo aluminum caliper which was dropped in favor of a cast iron ATE caliper due to noise complaints.

I wonder if the vehicle in question has the aluminum calipers which are supposedly more prone to noise or the cast iron calipers that were introduced as a solution to the noise complaints.

blackmercedes · #4 04-23-2004, 09:37 PM

We took the car out to ensure the brakes are working up to snuff. I did a about ten full-on panic stops and the brakes are working VERY well.

Well, after that, the pedal is feeling better and the grinding noises are gone. Jan retured home today with a smile on her face.