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TOPIC: Strange Brake Problem

Strange Brake Problem 15 May 2013 12:11 #14744


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I've got a strange brake problem on my '93 GTS. I go to a good shop (PowerTech NJ), and they cannot find the problem. The car starts shuddering for about a mile, and then I lose the brakes and the brake pedal goes down to the floor. Then, after the car rests for a while, the brakes come back. There is no loss of brake fluid and there was no warning message on the instrument panel. It sounds like an ABS failure, but wouldn't I still have a brake pedal? If there is no loss of fluid, then it is not an hydraulic problem. The car is now at the shop and does not exhibit any problems. Do any of you have any thoughts?
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Strange Brake Problem 15 May 2013 14:38 #14746


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My approach would be to drive the car for a few miles, then feel of each of the wheels to determine the brake temperature. If any wheel or wheels are hotter than the others, I would check for failing brake lines (swelling to cut the back-flow, causing the brakes to remain slightly applied).

The suspicion is that one or more of the brakes are dragging, causing overheating and boiling the brake fluid. I would also flush the brake system, using new DOT-4 fluid.
Wally Plumley
928 Specialists
www.928gt.com
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Strange Brake Problem 15 May 2013 15:11 #14749


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Thanks, Wally. They already recommended flushing the brake fluid but I'll have them check to see if one of brakes is dragging.
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Strange Brake Problem 15 May 2013 18:53 #14756


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Does the 93 GTS have anti lock brakes? if so, then I would pull the fuse to see if the problem goes away. It is always a good idea to check the temperature coming off the brakes which you can still do.
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Strange Brake Problem 15 May 2013 22:17 #14761


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Brad,

Everything from '86.5 forward has ABS standard. It was optional from like '83 I think.

I agree with Wally and suspect it is one brake that perhaps has a sticking piston and is causing the fluid to boil and then BOOM...no brakes!
James
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Strange Brake Problem 16 May 2013 12:33 #14772


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It doesn't look like a sticking piston/caliper. Our theory now is that the ABS engaged in some way creating friction that boiled the brake fluid. Perhaps the sensors are dirty or bad. Remember there was a studdering for about 1/2 mile just before I lost the brakes. When we find the issue, I'll post the solution.
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Strange Brake Problem 24 May 2013 08:54 #14867


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my car overheated one day in the city, i stopped for a few mins to let it cool down, i hit the break before taking off once i re started. pedal goes all the way down to the floor. i let the car sit a little longer, and it was all back to normal. not a problem with the brakes since.
seems our brake system is very susceptible to heat.
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Strange Brake Problem 28 May 2013 08:09 #14894


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I would strongly suggest flushing the system. That should be done at least every two years, using DOT 4 from a new, unopened container. Don't buy huge containers of fluid, don't use old fluid, and never use silicone fluid.
Wally Plumley
928 Specialists
www.928gt.com
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Strange Brake Problem 10 Jun 2014 21:01 #17280


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Was this ever figured out? From what I've been researching, Master Cylinder issue/failure could be a possibility.
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