1989 Proportioning Valve leak

[marksatterfield]

The front portion of my proportioning valve is leaking. I've not been able to source the piece -- I've tried Ford, Advance Auto, Autozone, NAPA, and a few local shops. Ford identifies the same piece for a 1987 Ford Thunderbird V6 as E7SZ-2B091-A. (The part for a 1989 Ford Mustang is E7ZZ, not sure what the difference is.)

Haynes calls the piece a combination Proportioning Valve & Shuttle Valve.

The device has a bolt on the front and the rear (for factory assembly, I believe), with two inputs on top and two outputs on the bottom. The inputs are sourced from two of the three ports of the master cylinder. The front output appears to go to the rear brakes, while the rear output appears to go to the front right brake. The front left brake is driven directly off the third port of the master cylinder.

So a few questions:

1) How can I source a new/rebuilt proportioning valve? Or find a rebuilt kit? Or figure out how to rebuild it? It is leaking out of the front plug. I believe the proportioning valve inside also has a rubber gasket (from Internet searches) that will need to be replaced.
2) Why is the FL brake driven off the master cylinder, while the FR brake is driven off this valve? I suspect it has something to do with preventing a single point of failure.
3) If I can't get a new/rebuilt one, how can I repair the car? I'm thinking that I might have to buy an adjustable proportioning valve for the rear brakes, and somehow "straight through" the FR brake. Details would definitely be appreciated!

Thanks guys,
--Mark

Mark Satterfield - Florida, Miami, Clearwater, Tampa, Melbourne, Orlando - Computers, Engineering

 

[AKA3Toes]

---If still searching and haven't installed an aftermarket, universal, adjustable Proportioning Valve like those from Wildwood, contact Vanco Power Brakes and ask if they have one or can rebuild yours for you. They're a vendor on an International Harvester forum I have been a member of for almost 20 years. If they have Proportioning Valves for IH Scouts, then it's safe to say they have them for everything... LOL.

---Their website is kind of basic, so it's best to contact them directly than search. Maybe a good pic of yours will help... but I would think they could cross the part number. Problem with Prop Valves is they're usually a dealership part, so you have to deal with counter-monkeys at the dealership (often worse than big name, corporate parts houses) or a specialty company. Vanco's pretty fair on their prices, so don't let fear of a "specialty" company scare you... lol.

---Make sure you come back and post a part number for the one you purchase, so others can make orders quicker if they too need one. Though I have serviced two for Scouts that were in good condition (before I knew about Vanco), I would not suggest doing so. While most seals and such can be found at separate auto parts stores and some other odds-and-ends found at various home improvement centers, once you break something like a 20-year old brass screw that holds a valve seal, or mar the bore with rust scale while pulling the shuttle out. Then what?

---Good luck.