a number of methods if you have solid teflon type sealing rings on the input shaft.
You use soda can metal wrapped around the rings. Compress with hose type clamp. Be very careful and slow
Scarf cut the sealing rings and use the soda can metal is another method.
I prefer L cut sealing rings for ease of use - install
clearnace on clutch packs... plan for .010 for each double friction sided ... 5 frictions = .050 minimum