Coming back from the hardware today, put the brakes on but nothing, the peddle was solid as if it had stuck on something, so I got home alright to check it out, if you pump the brakes a few times it locks hard, can't push the brake peddle down and no brakes, let it relax and they work fine, it's only if you pump them a few times that it locks, anybody else had this problem or know what would cause it, (standard brake system 1963 bus)

sounds like air in the system mate.

is it 4 wheel drum??
what your saying is what happens when you have a booster fail on a newer bus with dics on front ??.

As Ian said, pending on what type car and year you are talking about.

If an old well worn car, you can (but not common) wear the brake master cylinder bore and this causes a lip. Then when you apply the brake the piston kicks a little sideways in the cylinder and can catch on this lip and this stops the piston travel. Feels like a hard pedal, but not really applying pressure to the brake fluid with the master cylinder.

If it is like this, you will need to bore it out or buy a new master cylinder.

Kev