proportioning valve

[GMC JUNKIE TOO]

I am going to be putting front discs on my 69 halfton as soon as the parts get here I need to know if installing a 72 prop valve requires any work on the brake lines to go on I dont have power brakes.

Thanks Ben

[Mike C]

IME, the best thing to do when converting to disc is to get a new complete disc line set from a 71-72 truck. The drum brake rubber lines connect to the truck behind the crossmember and the disc lines in front. You can cut the frame bracket off where the drum line attaches and after fitting the disc lines you can tack weld it on front. That is what I did on my 3/4 ton disc swap. This makes it look factory, then all of the lines hook up right where they should, how they should from the master, into the combination valve, then onto the discs.

[GMC JUNKIE TOO]

Thanks for the good idea, thats what I will do.

[SCOTI]

If you can't find the 71-72 stuff, 73-up will work just as well & are much easier to find @ wrecking yards.

Just pull the lines from the mstr.cyl. all the way back to the union under the pass side of the cab. 73-up p-valves mount on the splash shield in front of the engine so all that's required is a couple of holes be drilled (I also put small spacers behind it as well). Then, if your anal (I am), tweak the hard lines so they follow the frame as close as possible & all that's left is cutting the excess off the 73-up line that runs under the cab (leaving enough to flare it) & connect it to your original fitting under your cab.