brake issues help!

[darksaga]

I have a 68 gmc 3/4 ton pickup with a 73 front axle and a dana 60 rear I bought the truck a few weeks ago knowing that the brakes had problems.

I thought the reason was that it had disc brakes and still had a drum master so I bought a a new (not rebuilt, raybestos) master for a 71 (interchanges with a 73) (morine), I installed it but the booster pushrod stuck out way too far so I cut it (bad Iknow bad), problems was far worse.

I bought a rebuilt napa booster for morine brakes but the pushrod to the pedal was too long........ so I started to hunt junkyards for a mounting bracket that was longer coulden't find one. I look on ebay and there was a booster and bracket, bid win install.

that brings me to today I put everytthing back together but the pedal still sinks to the floor with the truck running I adjusted the pedal rod all the way out.

the calipers and ruber hoses for the front have been replaced (one of the bleeder screws broke) and I checked the back wheel cylenders for leakage.

I am running out of options, the master may be reversed I installed the front brake lines to the front (small resivor) and the back lines to the back of the master (huge resivor). My dad thinks it may be the prop valve or the rear drums may need to be adjusted