brake issues 51 chevy deluxe 216

anyone ever have this issue? my system is stock. my front left brake keeps engadging after the car runs warm and pedal get super hard.I have changed wheel cylinders, lines, rebuilt master. Going to try to wrap lines and exhust with heat sheild stuff. Can anyone think is there something I am missing or should try? Its get warmer here in FL and i dont want to not drive her....thanks johnny

 

mine stops on a dime.....does it pull L or R???

 

I trust your change of lines included the rubber hose.

 

Usually when drum brakes get hot they react the other way and you loose braking power instead of having the brakes lock up.
My first thought is that the residual valve in the master cylinder is holding too much pressure in the lines and not letting the fluid back in the reservoir of the mastercylinder. It could also be that the push rod is adjusted too tight and keeping the master cylinder piston from returning far enough to clear the return hole in the master cylinder.

This is a diagram of a 39/40 Ford Master cylinder but if you take a look at the By-pass port in the bottom of the mastercylinder you can see how the pushrod might push the piston in far enough to cover it up and cause pressure to stay in the lines.

Other things might be weak springs on the shoes on that wheel or springs installed wrong. Or something on the line on that wheel that is restricting the flow of fluid back to the master cylinder when you let off the brakes.

 

If only the one wheel is acting up my bet would be on a bad hose on that side. M/C problems would usually cause more than one wheel to drag/lock up.

 

wrong side..LF locks up...check right hose.. RF locks up, check left hose

 

wow! thanks for responding guys. i did change flex hose. on both L and R. and rear. after i rebuilt master I have no done any adjustments. it is the stock chevy. i may try to bleed all fluid out and see if maybe something got in line. but the diagram makes me now think it the master.....i did rebuild it and it was my first time....so i could have messed it up......johnny

 

OK : Being you were in the M/C check to see if you have the M/C piston coming all the way back to the stop in the bore. You might need to adjust the pushrod for a bit of clearance if it has none. I once bent the lock ring retaining the piston stop preventing the piston fully releasing ,took a bit to figgure THAT one out.

 

thanks guys. it been so frusrating, i have been fighting my brakes the whole time i have had her...johnny

 

If all the wheels lock up it might be heating of fluid. Sounds like only LF locks. Is the LF drum getting extra hot? Are the shoes dragging?

You must have backed off and reset all the adjusters on the wheel cylinders????