Inliners International Forums General Discussion Drive Train Help - Brake system driving me crazy

54 Bel-Air
4 wheel disc brakes
power master cyclinder
2lb residual valves

I can not get pressure on front brakes, have bleed until I am blue in the face. No leaks, etc. Rears work good, but fronts do not even have enough pressure to turn on brake lights (switch is in front system) Rear pads polishing rotors, front show very little contact.
This is not my first dance with brake systems, maybe I am not seeing the forest for the trees
Open to ideas, thoughts, etc..........................

Thanks

Did you bench bleed the master before installing, by tipping it one way and then the other?

I've had something similar happen before, and for me, I broke the line loose at the master cylinder and had someone push the pedal down, then tighten the line up before releasing the pedal.

Is the front system residual valve in backwards? It shouldn't keep you from getting any pressure (as you describe) but it would make the pedal 'spongey' (like there was air in the system).

What kind of proportioning valve do you have? If it's a combination valve, could it be in backwards?

X2 on bleed the MC at the fitting.

You say no leaks and power brakes, could the front circut be leaking into the booster?

Thanks for replys, I am going to remove mastercyclinder this weekend and check it out. All valves installed correctly.
Did not think of leaking into booster.

Well I took M/C off and bench blead it again, checked for leakage, etc. Reinstalled, went back over eveything again like I had not touched it before. Got a hard pedal, brake light now works. Test drove, stops but can not lock any wheel no matter how hard I try.
Ran out of time, will rebleed system again any play with adjusting proportioning valve next chance I get. Things getting better but not there yet.

If the pedal's hard and doesn't pump up you don't have any air in the system.

How much vacuum do you have driving the booster? What it your pedal ratio, how big is the M/C bore? For that matter what front calipers are you running and how big are the rotors? Is the booster pushrod adjusted to fit your master cylinder?