Power Brake Issue = High Idle No or Little Brakes

I haven't asked a dumb question in a while and after a search thought I would come to the HAMB for help.

I have gotten my 48 back running and am having a brake issue. When I first start the car up and its at high idle there is very little or no brakes. As the car warms up and idle slows down I can pump the pedal and begin getting some brakes.

What I have is a firewall mounted Chevy booster, dual master cylinder with the Vacumn hose connected to the rear of an Edelbrock 650 Carb. on a 350 (yeah , I know). I am also using a Wilwood proportioning valve I even had a couple of buds look it over and everything such as calipers, lines, rotors etc are set up right. One thing that happened was when the system was bled the fluid more or less oozed out instead of a squirt. Rotors and calipers are mid size Chevy and rear end is original 48 Pontiac.

What do you guys think. Could it be the master cylinder or proportioning valve? I did open it up and got a little more brake but not much.

It's keeping me from driving and any advice is appreciated.

Thanks in advance!

48 Poncho

 

Do you mean that the pedal is hard (as in no vacume boost), or that the pedal is soft or goes to the floor? I don't know about pulling vacume for a brake booster off the carb base as opposed to the intake, but I've never pulled vacume from a carb base for the brake booster.

If you have to pump the brakes to get a firm pedal, sounds like you've got air in the system yet, not a vacume issue thought. A vacume bleeder was one of the best tools I've bought in a long time...

Brian

 

No the pedal is soft. Goes to the floor or real close at first. Then as idle slows the pedal gets a little resistance and I have some brake. Should I disconnect the hose from the carb base and connect to the intake then? Idle is very high when it first starts. Lines have been bled twice. Master cylinder remains full so its not leaking. I'm at a loss.

Thanks for replying Brian.

48 Poncho

 

I would say you have a vacume leak and or a leaking booster..............
Rod adjusted to booster?
Rod to M/C adjust?
Rear shoes if any adjusted?

 

Put a brake pressure gauge on a line and check the pressure.

 

Thats what I would look at first.

Take a vacuum tester to the booster.

 

Thanks guys. I printed off these responses and will be taking them to my friend's shop. If you come up with anything else, I'm all ears.

48 Poncho