ill do my best to keep this as sort and simple as possible! i was having problems with my breaks not locking up. my pedal goes all the way to the floor even when i slam it.
i took everything apart and noticed that my front calipers were not compressing properly. so i went and bought new ones and did a FULL bleed starting with LR,RR,RF,LF,LSPV. i got that all done, my bleeding was IMPECABLE(used a rubber hose in a bottle of fluid for each bleeder)
and i still have the SAME problem!! the only other thing i can think of is my master cylander going bad, could that be it?? while the car is off the pedal builds and holds pressure, but as soon as its turned on the pedal slowly hits the floor. or could it be my LSPV?

Sounds like the brake booster going out or a vacuum leak off of the booster.Losing any fluid?

no, i havent lost a drop. even before i put in the new calipers...

by the way its a 90 4runner 3vze.

well, this morning i replaced the master cylander(which i did bench bleed). then i went around and re bled the whole system for the 3rd time.
it still does the same thing. i really dont have money to have a shop look at it but if i have to bring it in, i will.
im totally stumped. please help <img src="/forums/images/graemlins/frown.gif" alt="" />

Any lift on the truck? If so, was the end of the sensing rod on the LSPV raised to account for the lift?

no, no lift. the truck is totally stock. it seems like a pressure issue. even after a full bleed, new calipers, and new master cylander, the pedal is kinda soggy till it reached the end(about 3 or 4 inches from the floor) the pressure builds up just fine when its not running, it gets nice and stiff.

Well, with the engine off, you have no vacuum assist on the brake booster. So you are feeling the unassisted master cylinder. Not sure if you have ABS or not, but one thing you could try for a test is to plug the vacuum line to the booster and then start the engine and see if anything changes with the engine running (and no brake boost). If nothing changes, it could be the booster. Or if you have a vacuum pump, try pulling a vacuum on the booster w/ engine off and see if it does the same thing as with the engine running (and booster connected).

Did you adjust the rear brakes?

ya, the rear brakes are adjusted. i just checked the booster check valve too. so there is no leak there.

Did you look over all your rubber lines to make sure none are bulging or something? Rubber lines are on the front calipers and rear axle.