This answer applies to model number DM4466-001. Look under the left wheel and you will see two plastic lugs, tapering to a point. Using a screwdriver, apply pressure to one of them at its thickest point, while pulling on the handle release switch from above. The clip will click out of place. Do the same with the other and the switch will come out. When replacing, the spring goes in first - it sits on a small plastic post. The handle release mechanism sits inside the switch and has its own plastic post which should be positoned in the top of the spring. Beware - replacing the components correctly is a fiddly business.
MP, January 2007
