I have a 1973 F250 4WD with power drum brakes. Recently the master cylinder started failing (brakes going unexpectedly to the floor) so I went to Advanced Auto and bought a rebuilt master cylinder. When I got the master cylinder I noticed it wasn't identical to my original master cylinder in shape and I needed to use a brass adapter to be able to attach one of the brake lines to the master cylinder.

I bench bled the MC first and it worked great but I was seeing brake fluid leaking from somewhere near the front reservoir.

Thinking it was defective I took it back and got a second rebuilt MC but it leaked too.

Reognizing that there is a high incidence of failures in rebuilt MCs I took the second unit back and bought a new MC.

The new MC was not identical to the original MC and it leaked too!

Of course AFTER all this I came to the website and searched "leaking master cylinder" and learned that for some reason after market MCs for Ford trucks tend to leak from the cover.

I can't use/swap the original Ford MC cover because the shape of the new MC is different than that of the original MC

Here is my problem:

1. I cant find a rebuild kit for the MC.

2. I am willing to buy a genuine Ford MC BUT I cant find a listing for the right MC for a 73 F250 with 4WD and power drum brakes. All of the aftermarket places I deal with do NOT have a listing for my truck/configuration

Does anyone know what original equipment Ford master cylinder will work on my truck and where I can obtain it?

Thanks,

Scott

 

For a Ford one you could try partsguyed.com or try egrbrakes.com

 

I just went thru this myself. My truck is a '71 and the master cylinder cover was leaking on my old one as well. However I didn't realize the outside corrosion was just as bad on the inside of the MC. This prompted me to go ahead and swap mine out for a new one upon closer inspection.
but I digress....
So to cure this I pulled off the bail and put it in a vise and cranked it closed,(the vise, not the bail) check frequently so the bail loop isnt closed to much it took some 3-4 trys before it stopped splashing out the top, that and not filling the MC so full.
I put a metal ruler on it and checked for gaps under the surfaces on the top edge when it got to the point of just a bit of splash coming out of the top, I finished the project with a small straight, flat piece of wood and a rubber mallet and tapped the top to square it.
I just took the truck out today, and checked it when I got home. No leaks this time.

 

I have wondered if it would help to machine the surface where the top seals to the mc, mine leaks but it doesnt bother me