disc brake pre72/post73 proportioning valves

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dhughens

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After significant searching, I cannot find if the later proportioning valve can be used successfully on an early disc setup. Specifically, using a 73-76 bbp, single piston proportioning valve, on a pre72 sbp, KH, four piston setup. I thought I saw this posted somewhere that it didn't matter but I cannot seem to find that post. Present setup will be early front discs with 9" rear drums.

My concern is the different caliper fluid capacities might need a different valve. If it is not an issue, how late of a valve can be used and from what disc brake car (aspen, volare, cordoba, etc.?) My intention is to presenly leave the 9" rears alone and eventually upgrade them to 11's or disc's when I figure what I am going to do with the rearend. I figure I will probably have to address the valve again at that time. Thanks, dan...
 
Not sure if is proportioning, or the valve just to turn on the light. Later MC's have the valve for the rear inside. I put a Masterpower kit in my 70, for front discs, good. Buddy put a different kit in a 69 b body, good.
 
I've noticed the "texas" valve on my 73 Charger looks identical to the one on my 87 5th Ave, which is also identical to all the late 90's Dakotas and Rams I've been looking at in salvage yards.

No idea if there's any difference internally, but I have a friend who says he has used late model truck m/c and prop/dist vlave to do disk coversion on 60s and 70s cars.
 
Frankly, if you are not concerned about restoration correctness, I'd get an aftermarket adjustable one
 
The same valve was used for disc brake A body cars from 71 to at least 1975. Youll have no problems using the later valve on a early car. This is a 71 and later disc prop valve for a body cars in the pic. kelsey hayes brakes were used till 72 and then the single BBP started in 73.
 

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That one's brass.
All mine are steel and rounded, with one of the front outlets at a 45* angle.
 
To my knowledge the cast valve your talking about was never used in an A body unless it was after 75. But both B and E body cars used the cast valve starting in 72. My listings dont go past 75 so after that I cant comment
 

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These disc / drum valves are the same. When you go to disc on rear use the drum / drum valve you are taking off.
 
The P valves just supply full pressure to the front 2 brake lines (common plenum inside) and then there is a spring loaded piston that is preloaded to like 300 lbs that gets forced back when you apply the brakes that uncovers the rear feed. Its a way to apply the fronts prior to the rears. It also serves as a brake warning light. I bet most if not all do the same thing and are biased equally.
 
Thanks for all the comments. I would like to repeat what I think has been said to verify. I can use any disc/drum proportioning valve from a 67-76 a-body to use on a sbp K/H front disc and 9"drum brake system. If I changed to 10" or 11" rear drum brakes, I would not need to change the proportioning valve as they are all the same. Would this be correct? Also, to verify, the drum/drum a-body valve would be used if I went to disc brakes front and rear? Thanks again, dan...
 
Come on people... this was getting interesting! More responses!
I was also wondering if the drum/drum prop valve is the way to go when doing a 4 wheel disc install.
 
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