Toyota Repair: Brake problems, brake cylinders, master cyl

Question
I have a problem with my 1988 yota p/u. i have to push the brake pedal down 3 times in order to get brake pressure, ive replaced the power booster and the master cyl and i  still get the same problem. I dont see any leaks anywhere. Could it be the LSPV valve? If so how can you bypass it? Thanks

Answer
It's not a good idea to bypass the valve even if it was possible, to verify if the valve is the problem the brakes should be bled of air, if no fluid comes out of the rear brake cylinders then the problem could be the valve which would mean that only the front brakes are working, if this is the case the valve should be replaced.