Disc Conv. Proportioning Valve

[Sinisterspeed]

Originally Posted by Burb

So Sinister, you are suggesting I add an additional 2lbs residual pressure valve as well?

I would have thought the new proportioning valve set for disc would already do this?

Never too old to seek knowledge ...

Here it is in a nut shell. I did alot of research on this subject because I did the exact same thing as was described in the beginning of this post. I installed a Dana 60 front (Disk) and a 14 Bolt rear with Disk brake conversion using front 3/4 ton components. After finding out that I could use the 7" dual booster because it also puts out 12-1400lbs however I couldn't use the stock prop valve for either of the trucks i parted out. One was drum/drum and the other was disk/drum. So, after much research. I found I needed to REMOVE the stock prop valve. I installed a 2lb residual valve for for the front before the "T" .
then installed the adjustable prop valve in line with the rears. I found out that the residual valve had to go in after the adjustable prop valve. So I installed them inside the rail on the pass side under the bed.

So, Yes Both the front and rears need residual pressure 2lbs for disk and 10 lbs for drum. And the only reason to use a the adjustable proportioning valve is to limit the pressure to the rears. I have mine wide open right now I couldn't get the brakes to bleed the way they said to adjusted during install. So its open all the way until I hit the road and then I will just pull over and turn it down accordingly.

The other problem you will run into is the residual valve and prop valve that you get from SSBC are for 3/16" line you will have to get adapters. I was able to pick these up at the local napa. The easiest way to do the brake line modification for me was just to replace the lines from the Master Cyl to the "T" in the front and the rears have a fitting just in the rail on the left side of the engine as well. You can tap back into them there and just remove everthing between.

If you need any more info on what I did any pictures or issues I came up with feel free to shoot me a PM. Seems easy but it took me awhile to figure it all out.

Others may have other opinions this is just what I did on my 70 4x4 as well as my Dads 55. Seems to work perfect.