3/8" 24 pitch. Almost the largest sized fine thread bolt you can find at "home de-pot (which I dislike but is the only hardware store open on Sunday around here).

So, I picked up a length of 3/8" ID steel tube, a couple 3/8-24 bolts (and nuts) and a couple small cotter pins.

I took one of the bolts and sawed the head off. I then inserted it backwards into a 5" length of pipe, (threads-out) and used my drill press to put two 1/16" holes through the pipe and bolt. I secured them with the cotter pins and then screwed the clevis into the other end of the pipe. The fit is tight enough to hold the clevis.

Lucky-for-me-and-everyone-else is that the clevis fits perfectly through the brake pedal.

This is great for the moment, but when I have a chance, I'll have a fine thread 3/8" nut welded to the open end of the pipe.

So, the system is back together, but I found a couple fluid leaks when I tried to bleed the system. So, once that's done, I'm ready to go.

I can snap a pic of the pin setup if anyone is interested.