The problem we had in production was primarily on the 998/999, late 90’s to early 2000.

There were two issues - the crappy seal material would shrink from heat aging and you would have difficulty getting third until warmed up. That was fixed by going to Viton seal material. Some guys in the dealers even wrapped string in the seal grooves to expand the seal.

The other issue was a mismachined front clutch retainer - the register on the piston would not allow the proper fluid travel from the hub to the piston. That was fixed by a new piston. The field fix we used in the interim was to place 4 equally spaced grooves to allow the fluid to travel.

The seal finish would have to be horrendous not to allow the piston to apply, or the piston bore grooved from piston cocking, or the inner bore very oversized from stock.

The short lip inner seal is more vulnerable than the old long lip inner seal.