brake dash light on...why?

[pseudoboyfriend]

Hey all,

THe dash light that comes on when the parking brake is set is on. Isn't normally in the morning, but after driving for a while it comes on and stays on (temperature sensitive maybe?). THe parking brake is not set (sets and unlocks just fine). All the wires, vacuum hoses, etc seem to work fine. Brake fluid levels are fine... The only thing that seems odd is that the parking brake cable is a little looser than it probably should be. Would that cause the light to be on? Can anyone think of anything else to check? Brakes work good and all, but the light makes me worry.

Isaac

[mrltd]

Does it go off if you pull the parking brake lever up?

[Archangel]

the prop valve is getting stuck maybe? I know that's what causes my brake light to be always on, I just pulled the plug off the valve switch and now light is on only when parking brake is on.

[pseudoboyfriend]

No. Parking brake seems to have no effect. I've wiggled, pulled, disconnected, reconnected, etc... mechanically everything seems fine.

Prop valve sounds like a possibility...

[1987cp]

Sounds very much like a bad proportioning valve, then. My solution (after driving with no rear brakes for a few weeks because of retarded factory crap) was to ditch the factory prop valve entirely and run the hardlines directly to the front brakes, and install a Wilwood adjustable proportioning valve on the rears. Best part is, you get exactly the brake bias you want without having to complain about the factory settings!

[pseudoboyfriend]

Now, the proportioning valve is part of the master cylinder right? So I'd be looking at replacing it, or doing as you say and getting an aftermarket valve and splicing into the front lines...hmm...

[1987cp]

Nope, the prop valve is very annoyingly located. It's down on the driver's side framerail way too close to the firewall, and it's next to impossible to get to, which was part of the reason I got totally fed up with it. It's hard enough to crack open 18-year-old brake fittings without being physically unable to get to them! :p The good news is of course that all you need to eliminate the factory prop valve is a brake line "T" from AutoZone, and some line and fittings. On one of my cars the single line going to the rear brakes rotted out under the driver's seat, so I just put a compression-fitting doodad in a convenient location and ran it straight to the master cylinder for the time being. Now I've got an extra adjustable prop valve on my desk that I need to install if I ever get around to it - full pressure to the rear drums at all times isn't a particularly good thing. :p

Dunno, maybe the pic at this link could help:

http://picasaweb.google.com/mcwest2002/CarPicsOctober06/photo#5005555353688226002