Put a new brake booster and master cylinder on my 65 convertible. After bleeding the peddle is very hard and no sign of the power brakes. The peddle feels like it has two stages, the first bit you just push right through and then straight to non power peddle feel. The car has drums all around and the cylinders are pretty new. The vacume pressure is 15 pounds at the booster which should give me something. Is 15 pounds enough for power brakes with drums? Thnx

 

15" Hg (not 'pounds' or psi) is a little low. Rev the engine up to 2k rpm or so and see what effect that has on pedal effort. You may also try driving it around.

 

I've driven it a bunch but there is no power brake feel. The pedal always feels firm. At one time the power brakes worked great but its been so long I've forgot what they were like.

 

To verify if the booster is working, pump the pedal 3-5 times with the engine off. Put pressure on the brakes and start the engine. If the pedal drops an inch or so once started, vacuum is there and working. If the pedal doesn't change, the booster is dead or not getting vacuum. While 15 inches is borderline, if it shows no response with this test, still hold the brakes firmly applied and goose and release the gas pedal. If the pedal now lowers where it didn't before, the problem is poor vacuum. Poor engine tuning, too much cam, etc.

For future reference, the measurement you are getting is 15 inches of vacuum, not pressure and not pounds. Just so ya know.