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Proportion Valve Blues

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Bruno2

Re: Proportion Valve Blues

I need to do this on my 96. I had an issue a few years ago where it was keeping the pressure on my rear drums after the pedal was released. I took the valve off and cleaned it. A new valve is like $280.00. That kept the brakes from locking down like they did before. However, I have eternal ABS light on. Seems like the ABS isnt working either. I did after extensive searching on the web find a tutorial on how to rebuild them, but it wasnt my valve in the tutorial.

Whitey: 1996 F 250 XL CCLB 4X4 7.3 DI ZF5 (The Work Horse) Lots of power mods
Whitey Jr: AKA Jr 1982 F 150 CCLB 4X4 351W C6 (Jr Work Horse) respectable power, but not over the top
The Bronco: 1987 Bronco XLT 351W C6 (needs work) Lots of off road mods and plenty of power mods
The Dodge: 2006 Ram 2500 CCSB 4X4 5.9 HO Cummins (The reliable ride that cant keep an AC in itself) (5th AC go around almost complete)

Gary Lewis

Re: Proportion Valve Blues

Administrator

This probably isn't your problem now that you have gotten the brakes to release, but there's an adjustment on the pushrod between the booster and the master. If you make that too long the brakes can't fully release.

Scott, the welder guy, and I found that out the hard way recently. He came over with his '78 with brake prob's. After bleeding and adjusting the rears we still had no pedal, so adjusted that rod. It made all the difference in the world, but the brakes wouldn't release fully. Backing the screw off slightly fixed it.

Gary, AKA "Gary fellow": Profile

Dad's: '81 F150 Ranger XLT 4x4: Down for restomod: Full-roller "stroked 351M" w/Trick Flow heads & intake, EEC-V SEFI/E4OD/3.50 gears w/Kevlar clutches
Blue: 2015 F150 Platinum 4x4 SuperCrew wearing Blue Jeans & sporting a 3.5L EB & Max Tow
Big Blue: 1985 F250HD 4x4: 460/ZF5/3.55's, D60 w/Ox locker & 10.25 Sterling/Trutrac, Blue Top & Borgeson, & EEC-V MAF/SEFI

Bruno2

Re: Proportion Valve Blues

Does the master need to come off to do this?

Gary Lewis

Re: Proportion Valve Blues

Administrator

Jein - German slang for yes and no. Pull the two bolts holding the master to the booster and tilt the master forward and a bit to the side. You'll see the pushrod.

The factory manual gives a precise length the rod should be and warns that if it is too long the brakes won't disengage. And, it shows how to make a U-shaped gauge to measure it, which is otherwise very difficult to do. We guestimated it and got it wrong, so Scott said he knows someone with a laser cutting system and was going to ask him to make that tool.

Gary, AKA "Gary fellow": Profile

Bruno2

Re: Proportion Valve Blues

This is my "ABS" light though. Is it the same issue?

Gary Lewis

Re: Proportion Valve Blues

Administrator

Maybe not. I don't know what causes the ABS light to come on. This issue causes one side of the brake system to keep some pressure in the system. So, would that turn the ABS light on?

Gary, AKA "Gary fellow": Profile