I searched for my exact problem and couldn't find one in the archives.

1969 car - running/driving until a year back when I started a 4 spd conversion and trailing arm rebuild. Brakes worked fine. So I opened the rear system for extended period of time while the arms were off. Now that all is reconnected I have ZERO pedal. I mean nothing - not enough to even bleed. It feels like just a swinging pedal can't make enough pressure to push fluid to the calipers and won't gravity bleed either. I've had soft pedal and sinking pedal but never zero. What to do?

 

I suspect the Master Cyl is full of crud. Pop the lid, take a flashlight and look at the brakefluid. I bet you can't see the bottom of the MC. Do you recall the last time the entire system was flushed? The "swinging pedal" sounds like the MC piston is stuck.

How did you open the rear system during storage / repair? Just let it drain or plugged off the brakelines?

 

Crystal clear fluid in the MC. Not even cloudy. Since it won't gravity bleed I decided I'll just pull the MC off and mess with it on the bench vise. When I disconnected the 2 lines, no fluid ran out. Shouldn't brake fluid run out if the MC is full?

 

It should dribble, is all. If you plan on bench bleeding again, operate the piston with the MC level in the vise, then a few strokes with MC nose down, then a few strokes nose up.
Do you have a MC bleeder kit?

 

I am seeing videos about the proportioning valve being tripped? I do have the brake warning light on. If mine is tripped how to you reset it?

 

Warning light is NOT on. Haha - I have the parking brake set...

 

It can be reset by stabbing the pedal hard. That will center the Proportioning Valve piston. BUT only if there are no open bleeders, leaks, etc. Meaning that all pressure, front & back are equal. Think of the Prop Valve w/ lite as a GFCI in home electrical circuits. Both will detect something is wrong and "trip". Both will go back to neutral, both need the issue resolved.

If you plan on using the pedal / pump bleeding method, you will need a little tool that replaces the Prop Valve switch. The tool about $12 will hold that Prop Valve piston centered for you while you do your "bleeding thing". It is NOT needed with the Vacuum style bleeding, gravity bleeding nor the Motive Power style.

To test the MC to see if it can even hold pressure, you will need two "test brakelines" that can be made up from your local parts store. And the front port on the MC not only is a different diameter, it is a different thread pitch than the rear. I had NAPA help me make two MC test lines. Basically a foot long, curved upwards to clear the fender, correct brass fitting on one end, closed off on the other end. Install those with MC on the car. See if the brake pedal / MC will hold pressure. If not, its get your wallet out time.

 

I have original lines that have been repurposed as hard bleeder lines for bench top use so all good there

 

The rear reservoir on the master prob drained out with the rear line open. Full of air. Bench bleed in the car, clear (important) hose from brake ports up and over into the reservoir half full of fluid. Watch the action of the air bubbles coming from the ports as related to how you manipulate the pedal. Takes some time and finesse to get all the air out of the master. If you just push and release the pedal it breaks up the bubbles and they move out and back into the master. With clear hose you can see what's going on, I push the pedal slowly and hold it while the bubbles move all the way to the top of the curved hose, back off the pedal very slightly and let them move up further, sometimes modulating the pedal in very tiny movements until I can push the pedal again to push the bubbles out, ...then repeat. Worth the trouble. Last one took about 45 minutes.

 

You can get a MC to hold pressure on the bench using a phillips screwdriver. But as soon as the MC is mounted in the car and using the pedal with alot more leverage, a bad MC will go to the floor. You can't apply enough pressure by hand in a vise. It will fool you sometimes.

 

Its not a "true Bench Bleed" if its done on the car. The whole idea of bench bleeding is to angle the MC up and down in the vise to get the last hidden trapped bubbles out, which can not be done on the car unless you want to put it up on ramps. See post #4.

 

Getting some tiny bubbles on the rear reservoir, nothing on the front, still zero pedal effort. Doesn't even appear to be moving fluid at all.

 

Ok. Just for the heck of it, take a line wrench and re-snug both brass line fittings at the MC. Or in your case, blue fittings.
Re-test for bubbles.

I don't want to be the one to tell ya, but . . . . . . . it doesn't look good.

Fluid looks pretty good buts lots of corrosion where the lid gasket rode indicating high humidity. What is the history on the MC? Original? Rebuilt? When?

 

I neglected to mention that I did angle the car up and down. Had it parked on my lift and would pick up the front or rear as needed. It is essential to angle it. But it's the best bench bleed I've gotten yet on any car. The vette seems to be the most stubborn to bleed. It really helps to have clear tubing and use the line ports to see what's actually going on.

 

Do you have an oil extractor? I have used these to pull fluid through the system, gets you to about 90% old fashioned pump bleeding after that.