Combination valve rebuild kit?

[MikeB]

Looking for a kit to rebuild an 82 C10 combination valve. Can't find anything on the Internet.

Would rather not buy a one-size-fits all valve.

 

[legopnuematic]

Other than finding a good used one, you may be out of luck, I couldn't find anything to rebuild the one from my 79, so I used the one from my 85 parts truck since the brake system on that truck did still work.

I did take the 79's valve apart to see whats inside and the condition and in the process the plastic plug for the brake warning light switch broke off with the threads still in the valve.
But its really a piston and a couple of O rings, you may be able to source correct o rings and give the bore a good clean and light hone.

 

[MikeB]

Thanks. I'm getting ready to convert to power, so thought I'd check out the 38-year old valve while I have everything apart. There are no obvious problems with my brakes other than they're manual and take a strong right leg! But brake fluid was pretty nasty when I went through the brakes a few years ago, and it wouldn't surprise me if the valve's seals are bad and/or the pistons are stuck.

 

[Nonstop]

I would not take it apart. If you are getting fluid out of each port, I would reuse it. IF you need a replacement, you might want to consider a junkyard unit or Wilwood. They make a valve similar looking to ours, and it goes for $95. I have done a few brake jobs that required the addition or replacement of the combination valve. I bought the valve from different sources. It looks like it is the same supplier, just packaged differently. 2 or 3 of them leaked within a matter of weeks or months and I had to replace them. Turns out it is a very common problem. When I was looking for replacements, it looks like wilwood makes their own and tests them.

 

[MikeB]

Unfortunately, I suspect most of the aftermarket valves are made overseas by the lowest bidders, and who knows where the "knee" is in the pressure chart? (Where rear pressure rate-of-increase starts dropping compared to fronts.) Car requirements are significantly different than pickup trucks.

Yes, Wilwood makes good stuff. I used their 4-piston calipers and 11.75" discs on the front of a 55 Chevy car, along with their 1-7/8" MC. Had a manual prop valve plumbed in, but ran it wide open because the 9.5" rear drums would lock up at about the same time as the Wilwood fronts.

Wish I had some way to test the OE combo valve. Not sure what it has for internal valving. Probably a metering valve for the fronts and maybe a residual valve for the rears. (?)

Might just chuck it, re-plumb, and go to a manual valve with separate residual and metering valves.