Hello.Changed out rotors,calibers,pads and flexlines on 98f150 ,4x4,4wabs. Did pass side first. Bled out new caliber, had brake pedal. Did same thing to driver side, now pedal goes to floor,just feel rear brakes stoping truck. Could driver side caliber be a bad rebuild?

 

Air probably got sucked back in when you did the drivers side. If the pedal was released before the bleeder was closed that would do it. Bleed them again and make sure the bleeder is closed before the pedal is released. Don't use a vacuum bleeder as that can trap air between the master cylinder and the ABS module, or in the module itself.

 

O.K.,I bled the hell out of the whole system,even bled lines in and out of ABS block,still have low pedal.Start truck,pedal goes to floor.I removed vac line from booster,startedtruck,pedal does not go to floor.Pluged vac line back into booster,pedal goes to floor.Does this mean booster is bad?

 

The only thing the booster does is provide power assist, it has no other effect on braking. I believe that '98 has rear drums, correct? Have you checked to see if a wheel cylinder popped? The only other thing that comes to mind is the master cylinder quit. It would be an incredible coincidence, but it could have happened.

EDIT:The reason the pedal doesn't sink to the floor when you disconnect the booster is because without the power assist it takes more effort to push it.

 

All the problems started after I replaced the driver side caliber,so I removed it ,got anotherone from advanceauto and instaled it. No More Problems!

 

If you have any more problems I would recommend replacing the brake hoses.