Brake warning light

[lifeinak]

I just did a rear drum brake job on my 72 and the brake warning light is now on. New everything including wheel cylinders. Anyone please direct me to the correct thread or details of where I went wrong. Blead rears only, do I need to reset proportioning valve? How can you not love this forum?? Best people, best info, best trucks. Help. Thanks

[pablo101]

I have the same thing on my 71, been told to center the proportioning valve..

Test Combination/Proportioning Valve

Use a test light by attaching a clip to a positive contact on the vehicle and touch the point of the tester to the electrical connection of the combination valve. If the the light does not come on, the valve system is operating correctly and no further testing is required.
If the light does come on, this indicates that the pressure differential valve is stuck in the front or rear position.
Bleed the brake system to determine if the front or rear lines are blocked off. Set up one front wheel and one rear wheel for bleeding at the same time. Crack both bleeder screws and gently pump the pedal a few times.
The blocked side will trickle fluid out when the bleeder screw is cracked and the pedal pressed. An unblocked line will squirt fluid out the bleeder.
The lines that are clear must be left open and the blocked lines should have the bleeder screws tight to cause pressure to build up on that side. Be sure to use the standard bleeding procedures to prevent air from entering the system.
Slowly press the pedal with steady pressure a number of times until the light goes out; this will center the differential valve. You may also hear a pop come from the proportioning valve. This is the metering valve returning to its equalized position. When the light goes out, close the bleeder screw. (See fig. below)

[lifeinak]

Thanks for the reply, I'll be working on it.