Prop valve question

[marts213]

I was wondering if I have the wrong proportioning valve on my truck. I have a 69 with front disc / rear drum. I saw a pic that Clemson71guy posted and it has one line going to the front brakes that splits and one line going to the back brakes that splits. (see attached pic) Mine has 2 separate lines going to the fronts (the 2nd line comes out above the rubber cover on the front of the prop valve). The rear looks to be the same.
My truck stops fine, but there is a lot of pedal travel (approx. 2 inches) before the brakes start to grab. I've bench bled the MC and bled the brakes numerous times, the rear brakes are adjusted tight, the booster rod is just about touching the piston in the MC, and everything has been replaced (MC, prop valve, power booster, calipers, hard lines, soft lines, rear wheel cylinders and drums, shoes).
The 2 things I've come up with on the old posts has been bleeding the proportioning valve (still not sure how) and that there should be a different hole in my brake pedal for power vs. manual brakes. Believe it or not, my pedal only has one hole. Thanks for any help.

Mike

[marts213]

Here is another pic of TCB-1's prop valve. Same as Clemsonguy's.

[cdowns]

what did the master cyl and prop valve come off of//different master and proportion valve for disc/druum and all drums

[marts213]

The master and the prop valve were part of a kit that I purchased. So everything is supposed to be for a disc/drum setup.

Mike

[Sammy]

Valve looks fine. But the Prop rod might need to be longer if you cannot adjust the 2 " out.

[cparman]

the adjustment in the rod under the dash is just for pedal height. IF you separate the booster/master there will be a rod 5/16 or so in the dead center of the booster. If you check the clearence, between this rod, and the master you might find your low pedal. If this was a manual brake truck, you should have had to drill a hole in the brake pedal about an inch lower from the original

[cparman]

i have done several of these drum to disc conversions, and have used Master power brakes for all of them. I have had to lengthen some of these rods before. MPB sells a tool to check this rod lenght. My redneck way to check this is to use a small ball of clay. Roll the clay into a ball, and stick it to the end of this rod. if it does not compress, MAKE THE ROD LONGER. it should have about 1/16 clearence. Common sense says make the rod longer UNTIL the brakes drag. Then grind off a scunch

[marts213]

I just have two follow up questions. I did have manual brakes before switching to the power disc. If I drill a hole in the pedal an inch under the existing hole, what will that affect? Is this also for pedal height? Or will this engage the brakes with less pedal travel? I will also try the ball of clay idea. I'm pretty sure there is very little clearance between the rod and the master, but now I will check exactly how much. Thanks for all your responses. Looking forward to getting this straightened out.

Mike

[cparman]

by drilling a hole 1" lower on the pedal you will change the ratio of pedal fulcrum? You are changing the pivot point from where the pedal mounts to the top bracket. Do the clay ball thing. it's cheap,easy, and will only take a few minutes to check. IF you have too much clearence make it longer and see what happens. If this fixes your problem, drive it around the block a few times, and let the truck coast to a stop. if it feels like the brakes are dragging grind just a little off.

There are instructions for all of this with pictures on Master Power Brakes site
www.mpbrakes.com