Hi,
I have a WM62.
Un plug the machine. Pull it out so that you can get to the back. unscrew the lower access panel off. Use a large pair of pliers to move the clips holding the rubber hose to the drum and pump. The filter is in they upper part, just below the drum - but its good to check no crap has built up at the pump end too.
I found a 20p and a plectrum in mine!.
Motorrobin
October 2007