Brake Light On - Proportioning Valve

Reply Subscribe

Thread Tools

Search this Thread

08-28-2007, 08:01 AM

zforce

Newbie

Thread Starter

Join Date: Aug 2007

Location:

Posts: 5

Brake Light On - Proportioning Valve

I have a 79 Camaro with front disk - rear drum brakes in which I replaced the hardware at all four wheels. I'm trying to bleed the rears, but I suspect that the proportioning valve is not centered becauseI cant build pressure andmy brake light is on.Any ideas onthis would be much appreciated.

Thanks
zforce

08-28-2007, 08:32 AM

thebandit110

2nd Gear member

Join Date: Jan 2007

Posts: 403

RE: Brake Light On - Proportioning Valve

there is a sensor on the prop. valve. did you put the cap on it??

08-28-2007, 08:56 AM

zforce

Newbie

Thread Starter

Join Date: Aug 2007

Location:

Posts: 5

RE: Brake Light On - Proportioning Valve

Yes, the cap is on the sensor. From the little that I've learned on these is that I suspect it is out of position internally, therfore not allowing proper fluid flow to the rear system.

09-05-2007, 06:13 PM

zforce

Newbie

Thread Starter

Join Date: Aug 2007

Location:

Posts: 5

RE: Brake Light On - Proportioning Valve

Here's the answer:

Test Combination/Proportioning Valve

1. 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.
2. If the light does come on, this indicates that the pressure differential valve is stuck in the front or rear position.
3. 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.
4. 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.
5. 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.
6. 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)