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Here is my 1978 dilemma : At low speeds, I hear a squeak from the passenger real wheel. It is not the brakes as they still have plenty of wear left in them. I did notice that the calipers may be rubbing on the bolt holding them together and I have tried to put a small drop of lubricant on this spot, yet the squeak comes & goes. Once the brakes are applied, the pitch changes. Any suggestions..
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Re: C3 1978 Break Squeak ... Calipers?
It probably has runnout on the rotors. This caused the pad to squeak on the retaining pin. -
Re: C3 1978 Break Squeak ... Calipers?
Steve----
There are 2 possibilities that come to mind quickly:
1) Just because there is plenty of wear left in the pads does not mean that they cannot be the cause of the squeeking sound. 1965-82 Corvette disc brake systems are of the constant contact pad type. Certain friction pad compounds will tend to squeek. In this case, just what you are experiencing will occur----the "tone" of the squeeking will change when the brakes are applied. The fix is to remove the pads (ON BOTH SIDES OF THE CAR), clean with "Brakeclean" solvent, if necessary; roughen the surface of the pads with medium grui sandpaper; and re-install. If this doesn't work, the next step is to replace them.
2) another possible problem is excessive disc brake rotor runout. This will cause the steel backing plates of the pads to rub against the calipers creating a squeeking noise, especially noticeable at low speeds. However, usually if this condition is the cause, the noise will stop when the brakes are applied.In Appreciation of John HinckleyComment
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Re: C3 1978 Break Squeak ... Calipers?
I put up with that annoying noise for some time. Forget the backing tape, lubes and other band-aid solutions. I went with Muskegon Brake organic pads and the problem disappeared immediately. People often think that this is a heat problem. It is not, particularly with semi-metallic pads. It is a cold problem: the pads are designed to work at high temps because they are in constant contact with the rotors. I suspect that you find the noise occurs in city driving and not highway where the heat builds up as it was designed to do. The organic pads are more accommodating as to heat ranges. They wear more quickly but are just fine for "normal" driving.Comment
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Re: C3 1978 Break Squeak ... Calipers?
The orignal '65 design pads were "organic" (non-metallic), and, as far as I know, only the J-56 HD systems used semi-metallic pads through the end of production of this basic brake system design in 1982. Of course, unless you find a set of OEM replacement pads that are at least 20 or more years old, the current compounds will not be asbestos based as were the originals from the sixties.
Unless you're using your car for track events, non-metallic pads should provide more than adequate brake performance, and non-metallics typically don't dust and squeak/squeal as much as metallics. In addition, current non-metallic pads should be easy on the rotors and wear well, but they might take a bit more pedal effort because of a higher Cf than asbestos based pads.
DukeComment
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Re: C3 1978 Break Squeak ... Calipers?
The early pads were asbestos-based: non-metallic. When those pads were banned in the 1970s for reasons related to carcinogenic issues, GM tried to compensate for lack of gripping/heat-resistant properties by introducing the semi-metallics. A compromise that has not worked for me for street driving. The new organic compounds are the answer. Not for competition mind you. But just fine for the street!Comment
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If it's not the brakes
You may be in the early stages of wheel bearing or u-joint failure.Comment
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If it's not the brakes
You may be in the late stages of wheel bearing or u-joint failure.Comment
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Re: C3 1978 Break Squeak ... Calipers?
My '81 has the same problem on the passenger side only for the 12 yrs I've owned it. I'll bleed the brakes and it goes away for a year or so. I believe since it is the farest from the master cylinder, a let up in line pressure causes it to move a touch slower.
FYI the rear bearings were replaced and rotors trued, made no difference in mine.
Later,
JUComment
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Re: C3 1978 Break Squeak ... Calipers?
I have found that a rusted off E-brake spring will be the cause of noise in some cases. It is more of a grinding at times and will come and go at low speeds but can also sound like a squeak.Lyle
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