John Struthers

Yeah,
I still have the black electricians tape covering my incessant brake warn pod light.
Just went thru the system again -two year service- : Disconnected Battery.
Pulled the wheels, calipers, pads, rotors. Pads and rotors still mic.' in the excellent condition zone for thickness, runout, no grooves/waves. No leaks anywhere! Pad wear sensors virginal. Pulled both pressure regulators aka
'switches'. Mighty Vac'd the system -flush- .
Good pedal, stopping power is MARVY. Hooked up the battery.
Still got the warn light ...bigger and brighter than Stuttgart!
Been thru the WSM's.
Tried everything/replaced everything mentioned/suggested here on the
Rennlist.
However, I do have a little used 1996 publication, Catalog Part Number
PNA 000147 A. The Parts and Technical Reference Catalog
Water Cooled Models 924, 944, and 928 Models 1977 - 1988.
On Pages 85 & 86 there is a simple check valve and grommet in the exploded view that I HAVE NOT checked or replaced as well as the gasket on the back of the booster and the grommet between the booster and Master Cylinder mount flange face. While there is absolutely no apparent fluid leakage what I am wondering IS can any of these above mentioned items be involved in a bleed down of pressure that would trigger the warn?
Guru's/ Brake experts? Neophytes? Anybody?

SeanR

What year is your car, and did you check the e-brake areas?

John Struthers

82', Weissach 4.5L, auto.
So, no ABS issues.
E-brake has nothing to do -as far as I know- with the closed, dual circuit, brake fluid charged system.
Additionally, the E-brake warn (on) is a separate sensor and wire circuit.

Ron_H

This may be unrelated but also may not. A day after the last Parade, we could run the autocross course again in small groups for a small fee. Of course i plunked down the money and gave it a vigorous go. (I just knew I could shave a few seconds off of my best time.) I scrambled, slid, bumped and rock and rolled around that course with a vengence. Just after the last run and on my way back to Norcal, the brake warning light came on. But I knew I had just changed the pads and the sensors on the fronts. I had been standing on the brakes a couple of times on the course that morning. I reasoned that I had disturbed the sensors and kept pushing the red button on the console to turn off the light and went on. After returning to Norcal, and after a couple of days, I noticed that the light would not come on and I reasoned that the problem had fixed itself by the sensors bedding down and stabilizing. (wishful thinking, huh?) Surely enough, the light came on again and then off. Then another day and it came on and then off and then on and off. Then it wouldn't come on at all........for a couple of hours. Mystery to me without tearing into the system. It now stays off for a couple of hours or more and then for some strange reason it will come one again. Guess it is time to open up all of the components and search. The car stops perfectly well. No problems there and the antilock system works well also.