weak disk brakes

[larsguitars]

Hey all,

I have just installed a four wheel disk brake kit from CPP on my 65 c-10. The brakes have been bleed and the brake pedal is solid. Problem is the brakes are weak and you have to push hard on the pedal. I need some ideas of what look for to solve my weak brake problem. The old drum brakes were much more powerful than the new disks.

THANKS!
Lars

[harpo1313]

are you running a booster?

[jayoldschool]

You'll need a new (disc specific) master to get good braking with front discs. Of course, power booster will help.

[larsguitars]

Hi Jay,

I have everything in the kit, dual master cylinder, booster, prop valve, brake lines, disks, calipers, the whole thing in one kit for my model of truck.
Lars

[larsguitars]

Hi

Yea I got the whole kit, double master cylinder, booster, prop valve, disks, calipers, lines, all designed to work together.
Lars

[brokenspoke]

Sounds like something is defective......I would contact CPP

[luvbowties]

Here's a second on brokenspoke's advice...
Sam

[Herman]

make sure the valve on the vacuum line is not backwards

[cortcomp]

What herman said, and of course, if you have a rumpy motor with like 10 inches of vacuum, that's an issue too. Also, i've heard of prop valves being kind of "Sticky" while pumping it up, tap on it lightly with a hammer, and bleed it again. If you're using a mighty vac, try the old method of having a friend pump it and hold while you crack bleeders.

If you want to be super diagnostic, get one of the pressure gauges that screw into a bleeder port and tell you the PSI you're getting at each wheel, will help you find out if it's an overall issue or just prop valve/master related.

Lastly, i had a problem like this in my '71 pontiac. Redoing the back brakes, and new pads on the front (EBC) quadrupled my stopping power, it was an amazing difference. Cheapy pads + not bedding in right kind of killed the stopping power. Back brakes helped from mildly leaking wheel cylinders. Likely not the issue on yours since you have new 4 wheel discs, just throwing it out there.

[larsguitars]

Thanks to all for the ideas.