1992 GMC Sierra

Brakes problem
1992 GMC Sierra V8 Four Wheel Drive Manual 170000 miles

The dash brake light comes on at different intervals sometimes quick some times 5 to 10 min. Why would it be on? The proportioning valve was ceeping so I replaced the it with a used one. It still ceeps but every thing is tight. The brakes are solid, the problem started when I replaced the rear differencial with a used one from a 97.
June 6, 2009.

The switch in the MC may be bad, any seeping is not a good thing. Brake connections are double inverted flare and should not leak, unless crossthreaded or bad flare.

Jun 6, 2009.