This is for a 1" Master Cylinder, NOT 15/16". Please check the stamping on the far end of the master cylinder next to the Mitsubishi Logo for a "1". Should also say NABCO on it. These seems to be European (EUDM) Starions and Japanese (JDM) Starions.

Make sure the bore of your cylinder is not rusty.

This is not just a normal rebuild but a full kit, includes all rubber seals, residual pressure valves, o-rings, new stainless steel bolt for piston, jubilee clip for fluid container, circlip etc.

The incredibly exciting rebuild video:

https://www.youtube.com/watch?v=kxzaojPlKbc