I have a 1994 Polaris sportsman 400. I need a rear brake caliper for it does anyone know where I can buy a good used caliper for it?

 

Used and maybe new type make model and year in ebay..

 

Agree, Ebay is the best place if you want one quickly (within a week or two).

Also check Craigslist in your area and you might find an ATV stripper who sells used parts. Sometimes you can find what you need fairly quickly. I generally use local guys for bigger things like fenders, clutch covers, etc. but usually this takes a month or longer to find something. If I need electrical or mechanical atv parts, I go to Ebay. You should be able to find a rear caliper very easily.

Good luck