Looking for assistance from the collective HAMB brain trust on an issue my cousin is having with his 1961 F-100 unibody. He has a re-occurring issue with his front brakes hanging up. It varies in pressure but most recently they were locked up enough he had to release the pressure from his wheel cylinder. Once he drove home it was already binding up again. I was leaning towards the rubber lines, as everything was replaced with new including the hard lines and master/wheel cylinders...however after replacing both rubber hoses with quality new ones there's no change. He believes it's both sides locking up but passenger side for certain as that's the one he bled (and it gets ripping hot) No deviations from the stock system, so it's a single master etc. Any ideas? Would this era of master have any sort of check valve that's sticking? Perhaps the new cylinders are junk? Thanks!