got a 52 chevy my break lock up all around adjusted front worked for a while now doing the same HELP PLEASE !

I was thinking proportioning valve but don't know if they had those in the early 50's. Are you talking all four lock up at same time when you step on pedal....then won't release....or locked up before you drive? Regardless, leaning to master cylinder

it runs without locking when cool but after driving a few miles using breaks they start locking up. I have open them up as far as I can, but when pressing them to break they lock up till cooled off.