Hi gurus! I am rebuilding the MC for my 1980 XJ650J and I'm having difficulty installing the new "piston cup" seal over the piston. I lubricated it w brake fluid but still... Ugh! Do you guys have any tips? What direction should I try to work it over? The threaded side or the end of the piston where the lever contacts it? It's very difficult to stretch onto the piston. The rebuild kit components are correct because everything is the same size.