I went through Chris Grim's thread collecting any extra information to add to the minimopar table (split pressures and ratios) in an excel chart. Failed to be able to read any tag (??) on my 1992 P bodies proportioning valve.
Looked in my 1992 FSM and P bodies both Drum and disc only use a Yellow 400 psi split .43 ratio valve.
There is a chart and none of the high pressure valves exist on the newer cars. 500psi is the highest but .27 .43 and .59 are all used.
I will post it up when I get some functional batteries.
Still mulling over in my head how the valves compare to the type of body and rear brakes used.
I think I will just type it up
AA 14" disc-drum 400psi .43 Yellow
AA 14" disc-disc 400psi .27 White
AP 14" disc-drum 400psi .43 Yellow
AP 14" disc-disc 400psi .43 Yellow
AY 14" disc-drum 500psi .59 Black
AG 14" disc-drum 400psi .43 Yellow
AG 15" disc-disc 400psi .27 White
AJ 14" disc-drum 400psi .43 Yellow
AJ 15" disc-disc 400psi .43 Yellow
AJ 14" disc-disc 500psi .27 Grey
Now, my attempts at understanding based on other threads i have read. One issue in my mind is the claim by some that disc brakes need more pressure to the rear..Maybe the old disc brake setups were just piles of crap?
The willwood brakes I am adding are 4 pot calipers vs our 1 piston calipers in front. But i think since these are meant to replace drum brakes they will not be a huge problem. I still want to understand our stock Proportioning valves before being forced to redo my brake lines like Brian.
I have the feeling the convertible option on some cars was an important determining factor for prop valves, even if most of them didnt get the option! thanks a lot James! (effin vert P body):P
AA 14" disc-drum 400psi .43 Yellow (240mm drums?)
AA 14" disc-disc 400psi .27 White (goes against the idea that modern disc brakes need more pressure)
AP 14" disc-drum 400psi .43 Yellow (220mm drums?)
AP 14" disc-disc 400psi .43 Yellow (not sure why the lighter P body gets more rear disc bias? This makes no sense to me. maybe it is because of the rear heavy convertible versions?)
AY 14" disc-drum 500psi .59 Black (heaviest drum brake car with more body weight in the rear, i can understand the higher split pressure and ratio though Vigo with his "cant tow as well as your 3.0 AA AY 3.3" might disagree)
AG 14" disc-drum 400psi .43 Yellow
AG 15" disc-disc 400psi .27 White (less pressure in the rear used, like the AA body 14" disc)
AJ 14" disc-drum 400psi .43 Yellow
AJ 15" disc-disc 400psi .43 Yellow (this 15" car gets a higher ratio then the G body, maybe because of the rear heavy convertible versions?
AJ 14" disc-disc 500psi .27 Grey (higher pressure because the 14" discs are less likely to lock up but once they split you don't want too much pressure? why does this car not use the 400psi .43 yellow? Is this a weird convertible issue again?)
Seems that they are more worried about having too little rear brake bias then too much. Worried enough that they over brake biased J and P body cars even in 1992 so that the convertible versions would be able to brake properly.
This is just a hypothesis but any suggestions?
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(This is what I originally wrote before I looked into what prop valve I had. I originally wanted to ask about a front/rear brake setup, deleting the diagonal setup.)
After seeing someone use some nice copper brake line that can be bent by hand, I decided it would be nice to change brakes lines from diagonal to front/rear. This would allow a single adjustable proportioning valve to be used. Adjusting two valves sounds absolutely terrible.
Brians post here on the subject got me worried and also a bit confused.
http://www.turbo-mopar.com/forums/sh...7&postcount=58
The easiest fix would jut be a