brakes on a 1/2 ton with 1 ton axles?!?!

[chevyridinhigh79]

my 77 k10 needs a new master cylinder and power booster i believe. i threw in a rebuilt set of 1 ton axles with good pads and rotors (condition of rear brakes is unknown, but the wheel cylinders don't leak!) i blead them 2 times this morning till there was no air in the lines and the pedal was rock hard, but as i was driving it to my house i ended up having to put the pedal through the floor to get it to stop. the power booster was leaking a little bit, but the fluid was hardly down at all. any ideas other than the power booster and master cylinder? when the 10 bolt and 12 bolt were in there with 31's the pedal and brakes were great. its got 33's now with the dana 60 and 14bff

 

[4X4HIGH]

You've probably got a bad master cylinder like alot of people do once they swap axles and bleed the brakes. Just install a new master cylinder and re-bleed the brakes and you should be done. Make sure though that there is no brake fluid in the booster or the diaphram will go bad on you.