Gotta love this site for getting answers! Thanks for the additional info Phil.
Here is my master cylinder from the side view:
- Master Brake Cylinder side view
The metal canister (in my case its aluminum) screws onto the top of the master cylinder reservoir with a rubber gasket in between. And the red cap with the cork float screws on the other end of the metal canister.
- Master Brake canister and SOVY lid
The rubber gasket that came with the metal canister is too thin as it won't seal the unit to the plastic reservoir. The canister is not an OEM version. Looks like someone custom made this.
The simple solution is to find a thicker rubber gasket. I need a 1-3/4" OD gasket that is 1/4" wide (thick). And it needs to hold up to brake fluid.
The more difficult solution and expensive to find an OEM canister. But after looking at Phil's photo it looks like it pressure fits on top of the cap (?).
I think I need to find a rubber gasket or O-Ring the right size. Any suggestions?