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Rampage rear prop valve leaks

1334 Views 7 Replies 5 Participants Last post by  87shelbyt2
My rear brake prop valve leaks and my brake man can't find parts or replacements. He says he's never seen such a setup before. Is there a reasonable replacement system such as from a minivan or maybe a K-wagon that can accomodate the load variations of a pickup? I currently have the complete brake system from an '85 Shelby Charger in place. I'm having new rubber lines installed from frame to hub to replace the old swollen units. But the prop valve is a problem I can't just remove as this is still a 'work truck' meaning I do haul the occasional load and I don't want any squirrely performance in the rear while doing so. Any help would be appreciated here.
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I haven't researched this personally, but I have been told by other Rampage owners that the valve is not available--new or rebuilt.
Since this is an '84 Rampage and the minivan first came out in '84, and they have VERY similar rear suspension types and load variables, could it be possible to use the rear proportioning valve from a Caravan? I'm desperate for an answer, this truck is due to go in for a paint job soon and I want the brakes DONE before it goes in. I've done a little research and the Caravan had a height sensing valve at least thru '85 model year, and some sort of a change was made in '86, but I don't know if it was eliminated then.
If you removed the valve all together, you'd probably be okay. The rear brakes would be "slightly" underpowered when you've got it loaded down. But it's not like you're running 1320's with a cube of brick back there are you? :D
Worse comes to worse, get two inline adjustable proportioning valves from Summit. Turn the pressure down so you don't get lock up when braking empty, then crank them up when hauling. I was going to do this with my minivan, but since I don't tow with it, I just ran straight line.

-Chuck James
On my Rampage i just got rid of that P.O.S completly, and built all new hard line. I also put in a regular proportioning valve from an 86 Charger, and it stops way better then the original setup!

Good luck on finding a good used one :)

First, thanks for alll the input. I've thought long and hard on removing the %#@! thing altogether, but Chrysler put it there for a reason and I remember reading about it at the time they were developing the Rampage that they had all kinds of handling problems until they worked out this brake/suspension system. I won't be hauling any really heavy loads (been there, done that, can't drive over 25 mph and the wheel bearings squeak all the way, and the load just behind the cab to distribute the weight evenly front to back) so maybe I can just do as suggested and put in the '86 Charger prop valve and remove the height valve. Is there any difference between the stock Charger and Shelby Charger master Cyl and prop valve? If I'm going to replace it I might as well put in a complete matched system. Are the later units larger bore masters for more volume? Thanks again.
I'm pretty sure the Shelby masters were a 7/8 bore. Not sure about the non-Shelby. It should be metal stamped on the top side toward the front of the master. Prop valves- again, not sure- sorry.
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