I'd like to share with fellow listers an interesting brake problem that
I experienced this weekend. Let me preface the story by saying
that the car underwent a thorough, concours quality, professional
restoration. I've put about 500-600 miles on it since without any
problems. Any input on possible solutions is greatly appreciated.
Twenty minutes into a leisurely afternoon drive I press the brake
while going into some twisties. A mile or so up the road the
brakes become a bit mushy. I come to a T intersection where a
friend who'd been following in another car informs me that my brake
lights have been on since braking for the twisties.
Meanwhile, the temp gauge is starting to climb (it had been running
cool up to this point) and I'm getting nervous she's going to spill her
guts on the road (the car, not the woman in the passenger seat).
Another mile down the road (brakes still feeling mushy and brake
lights still stuck on), all four brakes begin to smoke. No safe place
available to stop. :-( Another 0.5 miles and I reach my destination.
Smoke's pouring off the brakes!!! I can't decide whether run for my
fire extingusher or hots dogs for an impromptu "weenie" roast. I
opt for a cold frosty one instead, letting the car cool down for a
couple of hours.
The car's complete cooled down, so I start it up. Brake lights have
gone off and no more mushy pedal feel. Brake fluid level is OK.
The brakes seem to be operating fine.
When I felt the mushy pedal, I immediately assumed either a fluid
leak or a failing booster. I've found no obvious evidence of leaks or
disappearing fluid. The fact that the brakes went back to working
perfectly after the car cooled down makes me want to rule out
gradual booster failure.
So what else is connected to the booster? The vacuum line. All of
the evidence seems to point to it. Here's my theory: when the car
gets up to operating temp and stays there for around 20 mins (or
maybe this is the time req'd to reach a certain vacuum pressure?),
something funky happens to the vacuum line/pressure, causing the
booster to temporarily malfunction. Further, I think the problem
with the engine seeming to run hot is a result of the super high
underhood temperature generated by the sticking brakes, not an
inherent engine/coolin problem.
What do you think? How can I test the system to see if the
vacuume line is indeed the problem? What's the solution?
Thanks,
Gary
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