Master Cylinder

Friday was the day to travel to Rapid Racing in Clermont to see Greg Wright about some brake kits.  Dad and I had a good time talking with him about the old days, health problems, and, umm, karting.

Rebuilding the brake master cylinder was the main topic of discussion.  To rebuild or let it go?

If you rebuild, do you get the whole kit or just buy o-rings from an auto supply store?

Since the kart has been dormant for 40 years, all the old timers say to rebuild everything.  So we better rebuild.

First, was figuring out the mechanism.  The set screw on the outside needed to be removed, but it was a challenge.  I selected the wrong screw driver (needed a wide, thick blade, not a thin regular blade.) and promptly slightly stripped the slot.  But with some vice grips, pressure, Blaster, and Dad's persistence, it finally started moving.

Here it is with a "little" wear.  It might need to be replaced.

The set screw sits in the hole at top of master cylinder and holds in the top-hat-looking thing, which is actually the piston.

Here is the piston and spring.  Notice black scum on the piston.  The "cup" gasket is on the right end with a tiny metal plate inside it.

The reservoir was full of a mix of new clear fluid and old, grimy gunk.  After dumping that out, I discovered a good layer of gel on all the surfaces.  That took some cleaning.

 Here is the cylinder housing.

Notice the scalding on the sides.  That cleaned up just fine.

After that we headed up to the Autozone to pick up some o-rings and seals.  Rebuilding is for next time.