[mrk62]

I have a 74 coupe My rear brakes are locking up. ( I know drivers rear wheel is) could you tell me the problem. The pedal feels spongy. Its full with fluid. Not see'n fluid on back side of wheels. do'nt lock up in reverse.

[Blade10]

are they locked all the time? If not, you might have a bad proportioning valve. If they are locked all the time you might have some stuck wheel cyls.

It also sounds like you have some air in the lines.

Blade