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Old 12-15-2003, 02:08 AM
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unkl300d unkl300d is offline
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Join Date: Jul 1999
Location: San Francisco, Ca
Posts: 2,207
Tech advice please-C280 brake noise..calipers?

Hello. I hope to have a tech give an opinion in order to get me to the next step.
Recently my low milaage 1995 C280 developed a 'dampened' brake pedal. The car seemed less efficiently braking and the pedal felt heavy when braking.

I had my indie change all four rotors and pads since the rear rotors were scored and the pads seemed close to ready for new.
The front rotors did have lip and the pads were at about 25-30%.

I figured that this would resolve the problem.
The road test after the new materials still resulted in a heavy pedal but it seemed to get better progressively. It did brake more efficiently , however.

The owner was not available at the time and the mechanic
in charge tested the vacuum of the master cylinder. It was OK.
I decided to observe as I used the car.

A couple of days later, the brake pedal seemed normal, braking efficiency was excellent but the pads squeaked terribley after the car was braking downhill.

Earlier the shop owner left a message for me stating that he was concerned that my calipers may be faulty since the heavy pedal was reported to him.

At no point in time before or after materials replacement did the brakes pull to either side and before the new pads, the brakes did not squeal at all.

The shop owner asserts by phone that the pad squeal is symptomatic of bad front calipers. He states that the pistons are not releasing back fast enough. He does not agree that it is just a matter of adding brake paste. He also tells me that he does not like rebuilding calipers because of failure rate etc.

My current observations after about 300 miles of usage is that
there still is no pull, car brakes well, pedal sensitivity seems normal but the pads still initiate squealing after braking downhill.
Once they heat up downhill, they begin to squeal alot and then even on flat road.

An exception occurs periodically in that the pads do not squeal
after downhill or flat surface but may develop later in the day.
So the squeal is inconsistant but does initiate 98% of the time.

Over the last two days I have heard a faint 1-2 seconds of sudued squeal pitch sound during normal driving without brakes applied. This has been a rare occurrance so far.

Question is, does this sound like a job for brake paste (no paste on pads right now) or does the caliper theory sound plausible?

If calipers are at fault can they be rebuilt with a kit reliabley by a mechanic?

Thank you.
1979 300D 199 K miles
1995 C280 95 K miles
1992 Cadillac Eldorado Touring Coupe 57K miles
1979 240D 140Kmiles (bought for parents) *SOLD.
1989 300SE 148 K miles *SOLD
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