1979 FORD BRAKES MASTER CYLINDER ?

I seen it once before - master cylinder fluid at even in the pools - pedal almost to metal - front pool the small one is for back brakes drums - large pool back go's front brake's - there are 3 O-rings in the master cylinder which O-ring is shot - cap rubber small down large up - I know how to rebuild a master cylinder - and the car is parked - I can do it all - price it for parts 385.00 all - my labor - piping extra - front to back 1-2-3 and why ?