Please help, brakes suck on 72 c/10

[robert shaver]

I have a 72 c/10 that i am about ready to go crazy with. I just got this truck and the brakes have never stopped good since i,v had it. It does not have soft pedal and it doesn't go way down to the floor, feels like it should stop on a dime. But, this thing does not like to stop, it's got power brake booster that is working, i can feel it helping the pedal. I have to stand on these brakes to stop. I have switched master cylinders, no help, I took some of the proportioning valve apart part way, ( took off big nut and spring off end) looked good. I even capped off the port that feeds the rear brakes to see if the front discs were working some and they seem real week. the only other info I can think would be importent is the truck does stop in a straight line no pulling side to side, Right now i,m leaning to a bad p valve, but any help i would love

[oldblue1968chevy]

interested in this too...my brakes hold and stop crappy, let us know if you put a new vavle on and where ya get it and how much, and if it helps!

[my67c20]

So i take it that you have disk front. When as the last time the brakes were bleed? Have you had to top of the fluid latelty? How long have you owned the truck? Is the booster really working? Were is the booster plumbed to (manifold right)? Have you had the rears apart and adjusted them properly? When you switched the master cylinder did you make sure the pushrod was the right lenght? Did you bleed the MC before you put it togther? Just need more infor to diagnose properly.

[oldblue1968chevy]

hmmm

does anyone know the length of power booster rod? I wonder if i could have forgotten to swap it out, so no matter HOW much i adj. it does no good?..

[13lazer]

Originally Posted by oldblue1968chevy

hmmm

does anyone know the length of power booster rod? I wonder if i could have forgotten to swap it out, so no matter HOW much i adj. it does no good?..

there are two or more manufacturers of boosters from the factory, bendix and something else. i had to cut the power booster rod down and then grind a hemispherical tip on it to make it fit when i swapped my booster.
maybe you have fluid or grease on your rotor or drums. that will keep you from stopping for sure.

[cdowns]

have you replaced your pads and shoes?

[oldblue1968chevy]

me? yes. but i think your talking to the guy i hijacked the thread from..lol

[robert shaver]

today i took the proportioning valve off of my 72 blazer that I know works and put it on the truck. Brakes still hard. took all rubber brake hoses of and they are not swollen shut, pass air fine. decided to take booser apart. after beating on it for a bit I got it to seperate and found the back rubber diaphram had a 2 inch tear in it, so I hope this will fix it. i'll keep you guys posted, he's a pic of the truck a couple weeks ago after i painted it, I was still cut and bufing it in the pics

[Lee H]

Glazed over pads/shoes and or rotor?

[robert shaver]

today I got a new booster at carquest, $109.00 and it fixed the problem, so I am going to start enjoying it now. thank you guys for all the help, this is the best board.