Toyota Repair: Toyota Camry Brake bleeding problem, power bleeder, toyota camry

Question
I have a 1998 Toyota Camry 4 cyl. ABS. I changed the master cylinder because it was leaking and the pedal feel was way low. After replacing we tried to bleed the brakes. The Passenger front and driver rear bleed perfect. The driver front and passenger rear will not bleed. We tried a power bleeder to no avail. I even took back the new mastercylinder, bench bleed a new one and this didn't fix it. My father is convinced its the proportioning valve. What could casue this problem- we are going crazy. Thanks in advance Tony

Answer
The proportioning valve only affects both rear wheel braking, it does not have any effect on the fron wheels, there is no special brake bleeding procedure even with ABS, the manual states to bleed both rear wheel cylinders first, if this is not done the front cylinders may not bleed.