how do i mend leaking pump simpson washing machine?

You are wasting your time. The impellor is molded in place on the end of shaft. It will come off with strong force but usually stuffs it altogether. Even if you get it off you can't buy a rubber seal as a seperate spare part. They usually leak because the centre hole of the diaphragm seal wears away. Go buy a new pump.

Lincoln Appliance NZ
April 2010