NO BRAKES! Update, ITS FIXED !

[Maryland Bandit]

79 T/A, 403 car. Background info:
 Pedal went to the floor couple weeks back after a 350 mile trip to WV POCI event. Trailered it home with a U-haul. Master cylinder piston went it REAL easy after I removed it from the car.
New master cylinder from MP BRAKES,  put on, bench bled
New rear wheel cylinders a month ago
New front calipers last night.
Went through a quart of brake fluid so far bleeding all 4 wheels. Shar's son is a Ford tech, he helped, so we did it right.
Booster will hold pressure. Hours after shut off, pull the vacuum line off the booster and it hisses when you pull the line off. Booster is 4 years old done by Steve Gregori.
Proportioning valve is 4 years old, new style, all brass one.
While bleeding, engine off, the pedal firms up, goes to the floor when the lines cracked. Firms up again on 3 pumps, then crack the screw again. Did this like 4-5 times on each wheel, and at the master cylinder above the proportioning valve.
When we bled it, he did get air from the rear master cylinder line, and from both rear cylinders and one caliper.
Got done, fired the car up and eased down the driveway. Went down the road, and pedal goes to the floor and its everything I have in my leg to stop this darn car. Only going 5 mph too.  Fluid level full to the top.

I'm frustrated, scared to drive it, and out of answers. I'm thinking of dropping it off at a repair shop and letting them have a wack at it. Thought I would give you guys a shot too. It's got to be something obvious and simple.  Lets hear it.

[watchn]

I wonder if maybe u just got a bad master. Even a new one can be bad. Not much quality in new stuff anymore.

[Maryland Bandit]

This ones brand new, not a reman. When I bench bled it, you had to push HARD on the piston to get the fluid to move compared to the old, defective one. 

[Paul Kenney]

Tom I know you said the booster is holding pressure but I would ck it again. Booster/MC sure seem to be the suspect.

[watchn]

Yup sounds strange.. usualy when a booster goes u should still have a pedal you would  just have to push real hard but it shouldnt go to the floor. If it didnt go to the floor and u still had to push really hard i would say booster. It would still hold the vacuum but maybe the diaphram has let go inside. Also check if the new master on the back where the rod goes is the same depth as the old one. I'm sure you've checked all this.. just throwing out ideas.

[T/A GUY]

Any leaks seen anywhere on the car??,   if not>
Remove the master cyl. again and re-bleed it, this time go very slow when pushing in.
If you have plastic fittings screwed in the ports with rubber hoses to bleed, make sure the fittings do not leak.
Maybe better to just use rubber gloves to seal the ports when coming back on the piston.
Sometimes it will take 15 times bleeding it on the bench.
When you bleed it, go completely to the end 5-7 times
and then 5-7 more times but stop about 1/4-1/8" from the end.  
Put back on the car and bleed it at the 2-lines on the cyl. first then the rest.
NEVER pump the pedal when bleeding, Open,press down, Close,let up!
Or you let the shop do it.

[NOT A TA]

T/A Guy hit a lot of these points while I was typing but I'll throw it up anyway. Brakes is one of my least favorite tasks and yet I'm constantly doing them because I was killing pads, rotors etc on track so everything gets swapped out regularly. Putting in 14" Baers very soon.

Sounds like you have air trapped in the master not removed in bench bleeding. I'd take it out and start over. Did you use the old school style hoses that return fluid back to the res? If not, get a simple hose type MC bleed kit at the parts store. Those new things that come with a lot of MCs don't work very well for me. Did you tilt and jiggle the MC to get the bubbles free from the walls in the lower part when bench bleeding? I put the MC in a vise and push the plunger a bunch of times then remove the MC, tap it a few times and tilt it different directions then back in the vise for more plunger action. They seem to need a lot of bench bleeding compared with the modern plastic ones.

The 3 pumps to get a firm pedal usually indicates air in the system or rear drum brakes out of adjustment. Going to the floor when the engine is running also indicates air. When the MC is bad it usually goes to the floor (possibly slowly) with a good push even without the engine running. If it didn't go to the floor but required lots of pedal pressure to stop the car then maybe pinched vacume hose or bad check valve or bad booster.

If it seems like air, start over bench bleeding and reinstalling the master and get a Mity vac and bleed bleed bleed. Or if you're doing it manually then no pumping. Open, push, close, release.

As mentioned if the booster goes bad or the vacume hose is pinched the brake works but requires lots of pedal pressure.

[Grand73Am]

When it wouldn't stop on your test drive, did you check the master to see if the fluid level was still up? Obviously, if one of the compartments was low, you'd have a leak in that side of the system.

If after investigating further, you still can't find where the problem is, one way to isolate the problem to either the front or the back would be to clamp down on the rear brake hose, so it won't pass fluid to the rear brake lines. You could use some vice-grips with jaws wrapped in duct tape to try to protect the hose surface. Once clamped it isolates the rear brakes from the front brakes and lines. If you still have no pedal, you can assume the problem is in the front system. If you have a good pedal, then the problem would be in the rear.

In your bleeding process, after you've bench bled the master, you don't need bleed again when it's on the car.

And are the rear brake shoes adjusted out so they have a slight rub when the drums are rotated?

How old are the front brake hoses and rear brake hose? Old hoses can collapse inside the hose, and you wouldn't be able to tell from the outside. And then you wouldn't get fluid flow through that hose. So, if you've never changed them, it may be time.

Also, bleed the rear brakes first, bleeding the cylinder that's furthest from the front...on the longest line away from the front. Then the same for the front.

The Pontiac Service manual for your car has an effective and simple process written there for manual bleeding. It's a method where you submerge the end of a bleeder tube in a glass jar of clean brake fluid. I use a large glass bottle and a length of clear vinyl tube. The tube is a diameter so that it will be a tight fit on the bleeder valve. So, you can see when the air bubbles stop as you push the pedal so you know the air is out.

[Maryland Bandit]

I slept on it. I'm going to farm it out to those that know better then me. I'll be the first to admit when I'm over my head here. Being its brakes, and your life depends on them, thats no part to be guessing or messing around with, if your not sure on something. George and JP are coming to get it, then I know its in good hands. JP is old school, and loves these cars, man has forgotten more then most of us know. George also has the use of a complete auto repair shop at his disposal. That beats laying on your back in the 98 degree heat after a 10 hour day at work, hoping you fix a problem.

[mrbandit]

I slept on it.

I bet the neighbors thought you were strange sleeping on your car like that. 

[taman76]

That is a smart move.  No sense in risking your life to save a dollar.

[JNO]

Went down the road, and pedal goes to the floor and its everything I have in my leg to stop this darn car. Only going 5 mph too.

That must have gotten the old blood flowing! If it went to the floor how did you stop it? e-brake?

[Maryland Bandit]

Ok, every test we've done, now points to the culprit that JP said it was in the beginning, but I didn't listen. I had my terminologies backwards. I have whats called a HARD pedal. Not a soft, spongy one.
It feels like trying to stop a 4 wheel drum car, or how it feels when it stalls out and you hit the brakes, NO power assist. Ordering a new booster tomorrow, Ames has the caduim plated ones that are correct. Will start the removal process on Sunday.

[NOT A TA]

Check the vacume hose and check valve first as more often they are the culprit and not the booster itself.

[Maryland Bandit]

Did that earlier. You can blow OUT the big end, but not suck in. You can suck IN the small side, but not blow in, so I guess the check valves doing its job. Have 20" of vacuum pulling on the end of the hose going to the chck valve also. The booster DOES hold vacuum hours after shutting down the car and then pulling off the check valve. I spoke with Steve Gregori twice today on this matter. He's almost positive its NOT the booster, hasn't had but one go bad in 15 years on him. But with it running , and hitting the brakes, its like standing on a brick to get this car to stop. Wouldn't even want to TRY it any faster then 10 mph. It's like trying to push the pedal through the firewall to stop, but its not hitting rock bottom.
Called George tongiht, I'm going to attack this booster on Sunday and remove it, ordering one tomorrow from Ames. Steve can rebuild this one and I'll keep it for a spare, or ebay it, once its done. What really shakes me up is the fact that it went with NO warning. Drove fine for 5 hours and 350 miles to WV, next day, NO assist.