Toyota Repair: 1990 pickup brake booster problem, brake bleeder, wheel cylinders

Question
Hi Ted,

Here's a toughy. My t-100 pickup has no brakes, they sink all the way down to the floor...but there's no leaks anywhere. I replaced the booster and the master cylinder, both of which were original pieces. Now I get pressure when the vehicle is turned off, but the brakes are still not catching. Now, when it's turned on, pressure is lost and the brakes still go all the way to the bottom. So I checked the emission hose going to the booster, it's a little worn but no leaks. The small check valve is working properly: suction towards engine and air is blocked on the way back. I took the master cyl off and the same thing happens. The rod is being pushed out. Could something be clogged? if so, what?

Any help would be appreciated.  

Answer
The brake pedal going to the floor is always a hydraulic leak, the booster doesn't cause this, recheck the rear wheel cylinders for leaks, if there are absolutely no leaks there is air in the system and it needs to be bled out either with a brake bleeder or by manual means.