Possible Brake Problem, Trunk Release Problem

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04 Apr 2011 18:28 #4294 by Mike1210
I have a 1988 928S4 with 31,000 well maintained miles.
1. While I was driving it today, I noticed a couple of times when I pressed the brake pedal that it squeeked although it worked as usual. Then my brakes were kind of spongy and the pedal went almost all the way to the floor, but still stopped the vehicle. After driving several city blocks with typical braking for stop lights, the brake pedal was then fine. ??? Is this a problem I should address or wait for it to happen again? I saw no signs of leakage on the pavement under the car.

2. My trunk release (next to my seat) sounds like it is working, but unlocks the trunk now maybe every third time I use it; otherwise, I have to unlock the trunk with my key. What do you think is wrong here?

Thanks alot for any insight before I take it to the dealer, if necessary.

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04 Apr 2011 18:47 #4295 by 928mac

I have a 1988 928S4 with 31,000 well maintained miles.
1. While I was driving it today, I noticed a couple of times when I pressed the brake pedal that it squeeked although it worked as usual. Then my brakes were kind of spongy and the pedal went almost all the way to the floor, but still stopped the vehicle. After driving several city blocks with typical braking for stop lights, the brake pedal was then fine. ??? Is this a problem I should address or wait for it to happen again? I saw no signs of leakage on the pavement under the car.

2. My trunk release (next to my seat) sounds like it is working, but unlocks the trunk now maybe every third time I use it; otherwise, I have to unlock the trunk with my key. What do you think is wrong here?

Thanks alot for any insight before I take it to the dealer, if necessary.



Hey Mike, Glad to have you here.

I am guessing that you were driving very aggressively and that it is a hot day and that the brakes got to hot.

when the brake pads get to hot they will get a varnish on them that once cooled will come off with normal braking.

This varnish or glaze will cause a high pitch squeal

If the pads and rotors get really really hot, then the pad and the rotor will compress and the brake peddle will have to be pressed down further to keep the same pressure for stopping.

As far as the trunk goes, there is a part from Roger or 928 intel that will fix this. I believe the cam that pushes on the latch wares and a plastic boot is the fix. I haven't bought mine yet :(

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04 Apr 2011 19:09 #4296 by srshaw3
You could also have accumulated moisture in your brake fluid. Unlike brake fluid, water will compress. Considering the low miles, sometimes brake fluid isn't changed since the brake pads could still be new.

There is also a 928 symptom where the master cylinder leaks into the power booster, so there is no fluid leaking on the ground/floor. I don't recall is this is related to specific years or not.

I would definitely advocate having a good brake shop take a look, as no brakes is not an issue.

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