Topic: Master cylinder bolt

[ExportMach]

I rebuilt the OE non-power drum brake master cylinder for my Mach and the OE small bolt and rubber grommet on the bottom allow brake fluid to leak out. This didnt happen when I first purchased and drove it. I am wondering if I were to install the large head screw Ive seen from other Ford master cylinders along with a copper washer will seal better. Or maybe how I can modify my OE bolt. Thanks in advance.

[Bob Gaines]

I rebuilt the OE non-power drum brake master cylinder for my Mach and the OE small bolt and rubber grommet on the bottom allow brake fluid to leak out. This didnt happen when I first purchased and drove it. I am wondering if I were to install the large head screw Ive seen from other Ford master cylinders along with a copper washer will seal better. Or maybe how I can modify my OE bolt. Thanks in advance.

That is called a stop bolt . The problem is not with the head of the bolt but with a internal seals up where it stops the piston I think. The small hex head was typically a earlier style and the dome shape with allen insert was a later style . Dead nuts on sold the individual dome shaped stop bolt in the past but don't if they do currently.