Do Proportioning Valves Wear Out?

Judge Mills said
I am in the process from converting from 4 wheel drums to 4 wheel discs. Based on my research, I wouldn't stick with an old prop valve. I'd recommend getting an adjustable prop valve, like this Wilwood I picked up. In the long run, I think you'd be better off, especially if you route all those brake lines and you get a car that locks up the rear before the front. http://www.summitracing.com/parts/wil-260-11179

Just don't forget the residual valve if you use drums with that valve. Disks don't need them, but drum brake systems require residual pressure in the lines. Most of the drum valves are around 10 psi. Also, keep in mind that you probably can't use stock brake lines with that valve, so you'd have to make your own...

67Dart273 said
The outer housing might be brass but all the internal stuff "ain't." It's a high pressure control valve of sorts. Anybody thinks something like that can't wear out is kidding themselves.

Actually, most of it IS brass, as you can see from the rebuild link above. The springs aren't, and of course the seals aren't. But seriously, this is an extremely low wear item. I'd have no heartache whatsoever about running a used one that was cleaned up a little as long as it still had brake fluid in it when it was pulled (ie, seals aren't dried up). In fact, lets see, I've never changed one. Which means I actually am running several used ones right now. My challenger has somewhere around 136k miles on it (40k are mine), my Duster has 91k miles on it, the EL5 GT has 81k miles, and my latest project (shhh!) has around 124k miles. All of them work just fine...

zkx14 said
These guys have the kit and here's the instructions to rebuild.

https://www.musclecarresearch.com/1970-76-mopar-combo-valve-rebuild

Awesome. Great info there!