I have almost no brake pressure on my '71 Charger.

I believe all the lines are bled and there are no visible leaks.

In the process of troubleshooting, I have had the brake pedal at full travel.

My questions are:

1) do you think I messed up the master cylinder by flooring the brake pedal more than once?

2) is there any way to test the master cylinder?

Thanks.

Greg

Greg if you plug the MC with a pair of brass plugs(several $$$ at a parts house) the pedal will be rock hard & virtually no travel if it's good & bled out properly. also do this with light pressure & hold & see if it's loosing pressure between the cups. Going to the floor puts the seals on an unworn area which is not good for them but it's been done many times & not a critical issue. Once the mc checks out OK you could hook up one line & bleed it out & get it squared away & then do the other side,this helps narrow things down if you have problems figuring out where the air is.

Have you adjusted the brakes yet?

I don't think it's a brake adjustment issue, the rear drums are pretty snug going on. Maybe I will check that again just to be sure.

If I pull the lines off the MC and put brass plugs in, does that allow air into the MC that would throw the test off?

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Greg if you plug the MC with a pair of brass plugs(several $$$ at a parts house) the pedal will be rock hard & virtually no travel if it's good & bled out properly. also do this with light pressure & hold & see if it's loosing pressure between the cups. Going to the floor puts the seals on an unworn area which is not good for them but it's been done many times & not a critical issue. Once the mc checks out OK you could hook up one line & bleed it out & get it squared away & then do the other side,this helps narrow things down if you have problems figuring out where the air is.

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You can bench bleed the MC in the car by making some loop back lines. The 2 lines go from the outlet ports on the MC and loop back into the bowls. Once installed pump the pedal until you see no more bubbles in the fluid.

I suspect you're going to find the MC is fine, you may have to bleed all 4 corners several times to get all the air out.