School me on Proportioning Valves 72

[Eturnit3]

I have a few minor issues and I need some schooling. The truck is a 72-k1500 disc front on d44 drum rear on 14b. Replaced everything, new cylinders new master cylinder, booster is functional but not new. Bled fluid to all corners, but on the test drive I still have fairly loose feeling brakes. I adjusted the read shoes out to just barely drag when I spin them by hand. Half way around the block, I get a brake light on the dash (the one that normally comes on when my e-brake is on) so I guess my biggest question is, what does the light mean. I assumed it meant no fluid or short in the switch thats on the proportioning valve. Can anyone explain what this switch/senser does? School me guys Im lost.

[OrrieG]

The switch is in the center of the proportioning valve and sense when the valve moves to either side indicating loss of fluid in one of the circuits. Sounds like you need to bleed again. Make sure the front calipers have the bleeder on the top, they can be flipped side to side and will not bleed out with the bleeder on the bottom. When I've had mine completely apart it has taken hours and multiple tries to get all the air out. Speed bleeders are cheap and help. If the proportioning valve gets offset there is a procedure in most manuals on how to reset it. I've never done it, mine always seemed to find there way back to center on their own.