Tapping Master Cylinder Holes

Has anyone ever tapped the holes in either the brake or clutch master cylinders for easier reinstallment? and if so what size do you use, fine or coarse threads, thanks...

I use 3/8" coarse thread. No need to redrill the hole, just run the tap through. You will have to enlarge the holes in the pedal box, though. You other option is to use a thread insert for the standard 5/16"( I think) size. Or do as Tom B does and tack weld a nut on the backside

Hi Craig, I can not find my pictures right now, but I made myself a set of small, flat, "C" shaped plates with holes drilled in the outer portions and silver soldered the correct nuts to the plates. I could then install and remove the MCs from the front without having to alter or drill then MCs out. The plates fit over the throat of the MC, behind the front flange and used the same stock size hardware. It only took me an evening to fabricate them.

Jim B.

Yep, that's where the concept came to me from Gerry. Now I wish I could find those pictures.

Jim B.

While at work today I did an experiment with my old M/C and tapped it with a 3/8- 16 tap and although the hole size is .010 over the tap drill size for that thread, it still worked well enough to hold, I will add some Loctite threadlocker upon final installation when my new M/C comes in from Basil.