Brakes Locked Up...

[SteveHMaine]

Thanks Jim,

Do you know exactly what the fuses do and what effect they would have on the current (pardon the pun) situation?

All the brake components are good as far as I know, I do use a power bleeder and everything was replaced about a year and a half ago prior to a PCA event in NH.

This happened quite unexpectedly. Unfortunately my wife was driving the car at the time so I don't have first hand knowledge of the symptoms prior to lock-up. I drove the car the day before she did and everything was fine.

I discovered the problem about a week later when I tried to take the car out of the garage. Then she tried to explain to me what happened. She said the brakes siezed for a moment as she approched a traffic light, but that was it.

I'm suspect the master cylinder too.

Thanks,

Steve

[MNBoxster]

Hi,

@SteveHMaine, The highest likelyhood is that the Master Cylinder has gone the way of all flesh. The MC is actually made by Lucas and a generic part is available, probably saving some dough. The Lucas PN# is PMK483 (32066700) and is a direct cross-link to Porsche PN# 996.355.910.00

But, the F1 Fuse is a High-current, 50Amp fuse (think Fusible Link). It's located in the Current Distributor which is mounted on the Firewall on the passenger side. You need to remove some of the footwell trim to access it. It is sealed with a label to prevent unauthorized access. The Fuses are mounted using 5mm nuts and run (L-R) F1-F7. The F1 Fuse handles all the ABS hardware - Pump, Modulators etc. I'm not certain, but the default mode (Blown Fuse) could well be to lock-up the system as a safety feature. Since the issue as you describe it appears to be intermittent, my suspiscion is not so strong on this being the cause. You'd want to pull the link (F1) and test it for continuity.

The B9 fuse is located in the 2nd row of the ATC Fusebox. It's function is to regulate power to the ABS Module (Brain). Again, I don't what (if any) default mode exists. If these fuses, and all the other Brake system items mentioned earlier, check out, then I'd start suspecting the ABS Module for improper function. Keep us informed - Good Luck!...

Happy Motoring!... Jim'99

[SteveHMaine]

Great info on the master cylinder!

This is why I love this site and "Porsche People".

Steve