Water pump repair for swamp cooler (before you throw it away, try this)

Swamp cooler water pumps have never lasted me more than 2 years. These units used to cost less than 20 bucks and are now pushing 40 bucks on Amazon. I am now saving the old ones for parts and hoping to be able to fix and repair them instead of spending money on a new one. Plus, throwing these out is bad for the environment.