I found this excellent step-by-step procedure for doing the replacement:
http://brandonsprojects.blogspot.com...blog-post.html
Two things I'd like to add. The first is that compressed air (in a can if you don't have shop air) is handy to blow clean the switch, mine was filled with fluid. Use eye protection and wrap with a rag so it doesn't splatter everywhere. I further cleaned things up with Radio Shack contact cleaner and blew that dry also.
You also are going to need a 1" crescent wrench, as the shoulder width on the new switch is greater than the 9/16 width of the old switch.