On the caliper you replaced, is the bleeder on the top or bottom? Sometimes they get boxed wrong and you will get a right side caliper in a left side box.
With the engine not running, pump the brakes a few times until the pedal gets hard to empty the booster. Pause, then push the pedal down and hold steady pressure on it. Does it sink or hold steady? If it holds steady, pump the pedal and note where the padal stops. If it was low on the first pump then comes up, that would mean you have air in the system or your rear brakes need adjusting.

 

yes i think its rears need adjust cause whats happens it will bleed it the pedal will be frim them all or a sudden go solft when james is pumping i hear a hiss form the master cycder area and when he hit the petal the break boster ans master c move alittle

 

What Joe is trying to say is that when I am in the cab pressing the brake pedal, the master cylinder is making a strange hissing sound.

 

is that with the engine off and after you deplete the booster of vaccum? What about my other questions... Does the pedal zink with steady pressure? Will it pump up?

 

Thank you for your reply Bash.

The sound from the master is when the motor is off.

And yes, I do get resistance on the brake pedal, I can pump it, however its very soft and I can still push it all the way to the floor. Which was not the case before the incident.

 

if you have no vacuum in the booster, engine off, and hear a hissing from the master with the engine off, i would remove the lines from the master and cap the lines. then try it. if the pedal goes to the floor, and i think it will, you need a new master cylinder.

 

hey tom his truck has cc would that not work if his mc went bad

 

what is cc?

if you are talking about cruise control, that is shut off with the clutch switch or brake light switch. it is not controlled by the master cylinder.

 

oh i was cheing on line have they have two veriosns of the master c one with cruise contronl one with out

 

i don't know if the 94 has the cruise switch in the master or not.
i did not realize you were messing with newer truck. even so, the only thing the master cylinder switch does is turns the cruise off.
if you use a master without the switch port in it you just leave the wires to the switch off the switch and the cruise will be disabled. that is what ford does to trucks with the fire recall until they can put a fuse in the hot side wire.

 

It is possible that your RABS valve is causing the pedal to floor. The couple I've seen go bad, I used a long screwdriver as a stethescope and listened to the RABS valve while someone pushed the pedal. I could hear the spring in the accumulator creaking as it compressed as the fluid leaked into the accumulator.

 

i don't think it is the abs valve, because they said the master cylinder is hissing when the brake is applied with engine off and no vacuum. that is telling me the master is bypassing.

 

Well, we replaced the master cylinder and STILL no brakes.

This has been going on for over a week now. I need this truck for work.

I am *ucking losing my mind.

I do not know what else to do.

 

ok i got to drive the truck last night after the new master c was in instead if u pumped the breaks they got nice and firm but as soon as u gave it some gas they get soft again i tryed to adjust then about 4 time driving in reverse and stopping on it that seemed to help all so tested the vacum pump had the truck running and i felt it pull on my finger but i could pull it off while the truck was running all so we tryed to change the front line but the back nut is striped round

 

My guess is the rabs valve or the rear brakes are worn out.