After replacing the master cylinder I was unable to get any flow out of any of the six bleeder valves on the front calibers. I did get flow out of the bleeder valves on both rear wheels. The break pedal has good pressure and travels about 2 inches.

I am letting it sit for a few days, and then plan on using a vacuum pump on the bleeder valve and 20 psi on my pressure bleeding rig. Unless some one has a better idea or what I should do.

Any help will be greatly appreciated.

"I was unable to get any flow out of any of the six bleeder valves on the front calibers"
There might be crud blocking the bleeder holes.

Try removing a bleeder completely and digging in with a needle or something.
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1980 245 Canadian B21A with SU carb, M46 trans, 3:31 dif, in Brampton, Ont.

i use a pressure bleeder I got through FCP,works great.I have never replaced a master cyl.so Im not sure of that procedure.I have always fully bled every car I have every had & used only syntehetic fluid dot4,,sometimes when I stil had squishyness in the pedal ,,i just pushed the pedal up & down about 10 times before i opened the bleeders,, first time when I had the MC replaced by a mechanic he bled it on the benchtop before installation,,
BUT I have seen a lot of weird stuff come out including what could have been a prehistoric mosquito preserved in Amber!

Did you bench bleed the MC?

Yes I bench bleeder the master cylinder until there were no more bubbles.. However I did have an issue getting the break lines connected to the master cylinder until I disconnected the master cylinder from the booster.

The way I have always done it, and it has always worked for me, is to just push the front brake caliper pistons in. This will push air up through the master cylinder and out the reservoir. I would have bench bled the master cylinder before I put it in the car. If you do this and you have not opened the system anywhere else there should only be a few bubbles at most right where the pipes attach to the master cylinder.

If I can avoid opening the bleeder valves I do, because they are usually really rusty in the climate I live in. Drilling them out is not fun.

Hi,

Since you replaced the Master Cylinder did you measure the push rod distance coming out of the booster bolting face?
This can raise up a minor problem in bleeding fluid out from the reservoir, especially by external reservoir using pressure or gravity for sure!
When a replacement booster is changed it has to be matched to the depth of a new or old Master Cylinder as the manufacturing or rebuilder tolerances will vary at any time!
The MONKEY gets put on the installers backside as it is beyond their control. If you look closely for some fine print paper work on exceptions of liability. It is the Same seen on cans of spray paint!

The piston rod of the MC must not touch the boosters rod too soon. If it does, it moves forward and it can close off a port in the MC that is used when the brake pedal is not depressed or at rest at the top pedal height from the floor.

This "normally" open port allows for expansion of heated up brake fluid. Brakes calipers get hot from use and therefore gets into the fluid.
Also the systems total volume will contract and expands from plain olé ambient temperature change through out a day.
That's why it called a static compensation port!
The expanding fluid needs to leak back up into the reservoir from the entire system or otherwise the caliper Pistons move outwards and binding occurs.

In many cases this extra clearance gets ignored because of consumers willingness NOT to pay for great car manuals so consequently they are not an all "inclusive" manual.
An Example is like those books used in a classy school or those of manufacturers training manuals, for their, quote, "professional technicians." That is providing they are top of the class students or might be like those doctors who are below the top and still practicing. (:|)

The clearance is not always given in shop manuals but a rule, of a dirty greasy thumb, is around .5mm to .75mm or 0.020 to 0.030 of an inch or less. The Less being LIMITED to 0.010. Engineers don't want to give up very much stroke when it comes to amounts of brake power creation.

With this error floating around this can cause your brakes to drag when the brake pedal is at rest going down the road or raise its ugly head to create curious bleed out mysteries if you believe in Gravity&Time bleeding.

Anyway, something to consider that might be going on as this has beat up a many mechanics to write off or excused away to being "it is an old car!"

Phil