Brake Master Cylinder

['94IDITurbo7.3]

what is the size of the bore in the "bigger" master cylinder?

my mc says 1 1/8" on the side of it.

i am still researching possibly causes for my soft breaks. from a thread i read the other day i think i have the "bigger" mc. i am pretty sure my booster is at fault for all my issues.


thanks

 

[ADV]

The fsuperduty master cylinder on my truck says 1 5/16 on it.

 

[Reddually93]

The "bigger" bore one is 1 1/4 but ford discontinued them from what i heard.

 

[icanfixall]

Usually the rear self adjusting brakes don't do a good job of staying up where they are best. Then all the brakeing is transfered to the fronts and they overheat and crack the rotors. Plus they wear out wuicker. If you peddle is sinking when to come to a stop its happening because they master cylinder is attempting to fill the out of adjustment rear wheel cylinders. Sometimes the truck will creep forwards too. If the parking brake sets near the floor thats a sure sign the rears are out of adjustment. Try applying the parking brake a couple of clicks and take a slow test drive. If the truck stops quicker with the brake peddle higher up from the floor then you have found the problem. Applying the parking brake a couple of clicks causes the rear shoes to be closer to the drums and that tells the cylinders not much fluid is required to activate the rear shoes by the cylinders.

 

['94IDITurbo7.3]

rears are adjusted up so far that they have worn out in ~6,000 miles.

 

[icanfixall]

rears are adjusted up so far that they have worn out in ~6,000 miles.

Where does the parking brake set when the truck is parked...

 

['94IDITurbo7.3]

Where does the parking brake set when the truck is parked...

not sure.

when i am driving i can slam on the breaks to stop for a light changing colors or somebody pulling out in front of me and the wheels lock up pretty easy & pedal is kind of high. if i ease onto the breaks the pedal is soft/low and they stop adequately, but if traffic decides to all of a sudden slam on the breaks the pedal goes even farther to the floor and let's just say the pucker factor is much greater than stopping power. in that situation the wheels WILL NOT lock up. i have a vac gauge in the cab and that shows everything in the vac system is working as it should.

 

['94IDITurbo7.3]

i found this thread as well.

Zero Loss Break Booster