Master cylinder 1-ton 1966

[geasson]

Well, it is running. Rough but it is running. It has no brakes and fluid is leaking out the back of the master cylinder and leaking on the inside. I suspect a new master cylinder is needed or at least a rebuild kit. My issue is that I have the rectangular master cylinder and according to the catalogs, a 1966 should have a round master cylinder. Did the PO change to an older master cylinder or did the 1-tons continue using the rectangular master cylinder. Which one should I buy???

[Simonsays]

I think as long as the bore size is the same it shouldn't matter. I have a 3/4 ton 1966 and mine takes the round one. You can take your apart and measure the bore size of the piston. I believe I saw it's either 1 inch or 1 1/8 inch.

[Ed Snyder]

Originally Posted by geasson

Well, it is running. Rough but it is running. It has no brakes and fluid is leaking out the back of the master cylinder and leaking on the inside. I suspect a new master cylinder is needed or at least a rebuild kit. My issue is that I have the rectangular master cylinder and according to the catalogs, a 1966 should have a round master cylinder. Did the PO change to an older master cylinder or did the 1-tons continue using the rectangular master cylinder. Which one should I buy???

The one on my 1965 one ton is round, but it has a screw-on lid.

[geasson]

It looks to me like there is little consistency in master cylinders. I guess I will need to get it removed and measure the bore and them find one. THanks for all the input.