Posted By: B1arno
proportioning valve (update) - 07/05/09 07:13 PM
Problem solved! I looked for the pin mentioned a couple of times that needed to be pushed in or pulled out in order to bleed the rear brakes. I could not find the pin, so I disconnected the brake line going into the proportioning valve. Still no pressure. I went back to the master and bench bled the reservior for the rear brakes. Bingo! I apparently did not get the master bench bled well enough the first time to the rear brakes. Thanks to those that replied!
Arno
Posted By: RapidRobert
Re: proportioning valve - 07/05/09 08:01 PM
The "off center" refers to the electrical contact that will shift over to one side when either side looses psi which will ground the electrical nub on the outside of the valve & light up a warning light on your dash. No prop valve issues before you rebuilt the system? I know you know this but I'd check that the lines are routed correctly on it. Some suggestions: disconnect the incoming line from the M/C drum half & see if fluid is reaching the prop valve, if the prop valve has the metering pin pull it out(or push it in) I forget which. Still nothing, take off the prop valve & open it up(if they can be opened)& see whats the problem.
Posted By: Blue66Charger
Re: proportioning valve - 07/06/09 12:24 AM
If you're pressure bleeding (like pumping the pedal while opening the bleeder) I believe the pin must be pulled up during the process. If you use a vacuum at each wheel or the "drip method", it shouldn't matter. I'm betting that's the prob.
Posted By: Crizila
Re: proportioning valve - 07/06/09 12:59 AM
Your car should have a 2 function valve in it - combination porportioning and brake warning light. These valves rearly go bad and are not rebuildable / repairable / adjustable. The porportioning part of the valve reduces the hydraulic pressure to the rear brakes to prevent rear wheel skid during heavy braking. The warning part of the valve you already know about. If the valve is shuttled over, it doesn't block the brake fluid from going to the failed side of the system. BTW, pull the wire and ground it to make sure you have a good bulb in the dash - I'm not sure if it's seperate from the park brake light. The little stem at the front of the valve is only used for pressure bleeding the system. By pushing it in or pulling it out ( depending on the valve ) it temporarily defeats the front brake hold off system. On a drum / disc system, you have to hold off the fluid from going to the front brakes until there is enough pressure in the rear system to over come the brake shoe return springs ( 75 to 135 PSI ). That aint your problem. About the only thing you can do with that valve is pull it off and inspect the ports for any debree. When they go bad, it's usually because they leak