The Stovebolt Site Forums The Shop Area Driveline Master cyclinder problem has me stumped

This has me stumped. Problem: low to no brake pedal.
I installed a new CPP dual master cylinder with booster in my 1957 Chevy truck. It is all drums. It has all new lines and brakes. CPP said it did not need any additional valves.

It did not come with master cylinder bleeder kit, so I installed it as is and bled the brake lines at least 10 times at each wheel (starting at the outermost wheel cylinder). I bled the lines at the master cylinder multiple times, Now when I bleed any line there does not appear to be any air in the lines, I have used the pumping the brake method and a brake bleeder tool. Everything at the lines seems fine when I bleed them, but I still get no pedal.

At this point any thoughts regarding what to do next would really be appreciated.
Thanks,
don

Have you double checked the m/c push rod adjustment? Sometimes that will give you weird symptoms.
SimS

Have you adjusted the brake shoes on your new brakes? If they are not near the drums, you won't get a solid pedal, even when the system is bled properly. This is one of those "ask me how I know" kind of things.

Kent

I've tried just about everything. I called CPP and they will send me the master cylinder bleed kit I didn't get when I ordered it. If that doesn't work I will return the master cylinder, it is under warranty. Their tech support was very pleasant, no problem if i need to send it back.

Thanks for the replies, appreciate your ideas. I know it is hard to diagnose problems without actually seeing them. But sometimes just getting a new perspective helps.
Thanks,
don

One problem I encountered was a spacer that was needed between the master cylinder plunger and the booster plunger.

Does it seem like you get a full stream of fluid when you bleed, or just a short spurt before bottoming out?

The problem I had was the pedal would move a long way before actually moving the master cylinder. The booster would move the plunger towards the master cylinder, but wasn't making contact with the plunger in the master cylinder until the pedal was almost to the floor.

Are your brake shoes adjusted correctly as Lightholer suggests?

I also think bleeding the Master Cylinder can be your issue but while you wait for your kit (should be just two rubber hoses) I'd jack each wheel up and check for a slight drag of the shoes on the drums.

You don't mention if you have hooked up the booster or not. Without the booster operating, you won't feel much. With power brakes you have three things to worry about having right, 1. No air in the system, 2. brakes are mechanically good and properly adjusted with no leaks, and 3. Manifold vacuum. You should have at least 16" up for good brakes. If you have an L6, your vacuum port will be on the intake below the carb and on the carb base or just behind the carb on a V-8. Don't kink the vacuum hose.

Best wishes,

Les