Proportioning Valve in Brake Circuit????

OK I am stumped.
I have ITB Geo Prizm (Toyota) and ITB Corolla FX
I want to put an adjustable proportioning valve in to reduce rear brake lock up however the brake line circuit is not like I expected.
There is already a fixed proportioning valve in the circuit, then there is a seperate line to each of the rea callipers from that valve.
Also the front callipers come from the same fixed valve.
I know I do not want to put a valve on each rear calliper line as it would be very difficult to balance them both.

Any suggestions, ideas or do I just have to suck it up??

Cheers SteveP

I don't know for sure but maybe you need to block one of the rears at the exisiting valve, put the adjustable valve in the remaining rear line and tee off to each rear caliper. But then again I don't know so get some better advice.

Steve, on my 1st gen RX-7 there WAS a OEM proportioning valve in the circuit. From the OEM proportioning valve one line to each front & one line to the rear that split to a line to each rear wheel. I eliminated the OEM proportioning valve & continued to have the same lines to the front & rear while installing the adjustable proportioning valve in the single line traveling to the rear wheels. I will presume that with your OEM proportioning valve removed you can install a brake line tee someplace after your adjustable proportioning valve & before the rear wheels.

IIRC my master cylinder had two out lines for the front & one out line for the rear that all went to the OEM proportioning valve. Then the two front & one rear line came out of the OEM proportioning valve.

How many lines are "out" from your master cylinder & where do the lines go ?

I have the same problem of seperate lines to each rear caliper.

Has anyone done this?

Thanks...

~Brian

Actually, I have seen double installations. It can make sense. Having individual control allows you to tailor the force to meet your specific needs. Certain tracks are just made for trail braking, and turning, but often braking is compromised because the inside rear lifts a bit and locks. Having the ability to dial that one back, and the other one up a bit might be pretty handy...it might help lap times, or making passes, but it will for sure help avoid expensive flatspots!

(I haven't installed the setup yet myself, but have seen it in some cars)

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I know I do not want to put a valve on each rear calliper line as it would be very difficult to balance them both.

Any suggestions, ideas or do I just have to suck it up??

Cheers SteveP
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Kirk was just talking about his dual rear prop valve install in his ITB Golf. Check it out in the VW forum. Title is something like "golf version 3.2..."

Actually, if you use a click style lever unit, balancing them would be easy. (Those are recommended anyway for ease of setting on the track, easy confirmation of correct setting, and easier documentation and repeatability.)

NO, NO, NO, David, don't get drawn into this ass-a-nine thread any further than you all ready are. :018: