55 TBird Master Cylinder

[RossL]

Car is 55 with power brakes.............. everything (shoes, hardware, wheel cylinders, hoses, power booster, etc....)were either rebuilt or replaced

My original master need to be sleeved so I opted for a "new" master. When I first installed the replacement MC, the pedal seemed like it was not making positive contact when engaging the brakes. It didn't have the plastic cap on the end of the rod, so I purchased one. The cap took all of the slop out, but the brakes didn't engage in a predictable way. It seemed like when I needed the pedal pressure to fully stop the car I had to apply a lot of pressure to "fully" stop the car............ (this statement is not accurate before I put in the pushrod cap it seemed to need more pressure, after I installed the cap it seems too sensitive, see my post below)

The pedal also seemed to be a little higher than "expected" (the brakes never worked well since I've owned the car, so I don't have a frame of reference of a working brake system). When I installed the plastic cap on the rod, I "think" I left the rubber washer in the bore.

Today I removed the master to check if I left the rubber spacer..............I could not get the plastic cap out of the piston bore. The plastic cap would not budge. I had to use a propane torch to melt the cap. When the cap melted, if the rubber spacer was in there it also melted (so i have no real way to know if it was there or not). I ordered a new plastic cap today

Has anyone else had a problem with the plastic cap verses the rubber spacer? Any problem with the new master cylinders?

 

[paul2748]

once the plastic cap has been seated in the MC, it usually will not come out easily.. That is why you were missing yours in the first place, most likely. Using heat to me is a real big NONO.. I would have used a drill first, doing it by hand, not by a power drill

 

[RossL]

once the plastic cap has been seated in the MC, it usually will not come out easily.. That is why you were missing yours in the first place, most likely. Using heat to me is a real big NONO.. I would have used a drill first, doing it by hand, not by a power drill

Tried using a screw, drill, and a tap. It did not budge........ after an hour of "trying" more friendly ways I took everything apart and melted it


I also noticed the bore in the new master piston is smaller than my old one. and the bottom of the bore where the plastic cap rests was a little smaller

 

[miker98038]

Just comments and guesses. The my oem power brakes on the bird did require more effort that modern power brakes. Better than non power, but heavier than my buddy’s tri 5 Chevy, let alone the Chrysler products I remember. Second, best of my knowledge the power and manual used the same master, rod, pedal assembly etc. Just the booster was added. A smaller bore moves less fluid, so in theory it would require a little less pressure but more travel. I’d be suspicious of the “new” master you bought, but that doesn’t mean the original was really “original”. What was the source of the new master?

 

[KULTULZ]

All need to realize that today's CHI-CON SLOPPY-COPY parts are junk.

Did the MC come with a push-rod or did the instr say to use the old rod?

You kept the take-off OEM MC (SGL RESVR) (if it was factory or factory replacement part)?

When you replaced the wheels cylinders, did they have metric bleeding screws?
Were they correct sizes?

How long ago were they replaced and have you changed the brake fluid on a regular basis?

READ HERE - https://theclassicford.com/1955_Ford_272V8_tuneup.htm

 

[RossL]

The new master (I believe made in Taiwan) did not come with a pushrod. I reused the pushrod that has spirals at the end where the nyon cup fits

I still have the master that came with the car (bought the car last year, don't know the history of repairs made)

New wheel cylinders have metric bleeders. Everything was changed out in March 2024.

Another note when I tried to remove the master, I removed the 4 bolts and it barely moved. I had to use a pry bar to release the pushrod from the nylon cup that was also stuck.

I've been driving the car for the last 6 weeks, it does stop OK. But as I am braking if I don't start out real light on the pedal the car stops abruptly. (my original post above was not accurate in saying I needed a lot of pressure to stop).



I tried adjusting the pedal free play but I couldn't really notice a difference as I moved the adjustment to all extremes

 

[KULTULZ]

The new master (I believe made in Taiwan) did not come with a pushrod. I reused the pushrod that has spirals at the end where the nyon cup fits

I still have the master that came with the car (bought the car last year, don't know the history of repairs made)

New wheel cylinders have metric bleeders. Everything was changed out in March 2024.

Another note when I tried to remove the master, I removed the 4 bolts and it barely moved. I had to use a pry bar to release the pushrod from the nylon cup that was also stuck.

I've been driving the car for the last 6 weeks, it does stop OK. But as I am braking if I don't start out real light on the pedal the car stops abruptly. (my original post above was not accurate in saying I needed a lot of pressure to stop).

I tried adjusting the pedal free play but I couldn't really notice a difference as I moved the adjustment to all extremes

​

Next time, remove the push-rod at the pedal and let it slide out with the MC.

Where the push-rod is attached to the brake pedal (bolt), that bolt is an eccentric that allows adjustment of correct travel/pedal height for the push-rod (you have a WORKSHOP MANUAL?).

So the car stops well but is touchy on brake application? Where did you source the shoes? Did you replace the shoe retracting springs?

Did you discard the wheel cylinders? If not they can be lined and professionally rebuilt along with the MC.