pushrod,
51 1/2ton should be bendix,Correct, NOT Huck Style,My 51 is bendix.....
The rt front W/C COULD be hanging up.....
You already said you replaced ALL the hoses,that eliminates a collapsed hose not letting the W/C release.....
Make sure you have Both front brakes adjusted correctly,in other words try backing the right side off a tad,could be too tight,compared to the L F Brake.....
regards,Steve Sr.