How do you replace the water pump on a 1992 Geo Metro?

I can only speak for the 89-94 1.0L, if this is the same model seriously consider replacing the timing belt also. Reason: Same amount of work, only costs an extra $20, should be changed every 60k anyway (is probably overdue now), and could save you alot of time, trouble and money if your engine gets ruined. I only paid $15 for my 94 for this exact reason (slipped belt), and the new motor cost $500.

Strip the splash guard on the underside. Remove the air filter assembly, remove the belts (both), remove the five crank pully bolts, remove the four water pump pully bolts. Remove the bracket bolt to the oil dipstick. remove all timing cover bolts. With a piece of paper and pencil make a diagram of how the spring slide bracket, and tensioner roller are positioned on the block. That may sound stupid, but once off those parts can be confusing to re-orient correctly. Mark the crank cog and block with a felt marker, and the same on the cam cog and block, in case the engine gets turned a little while you work. remove the timing belt. remove the water pump bolts, now you can see the four bolts that make you have to take off the timing belt roller. You can do it without pulling the belt, but the roller has to come of anyway, which is pretty much like pulling the timing belt, so go ahead and buy a new one, unless you've had it changed in the last 10-30k. remove the water pump bolts, and pump. gently scrape clean all gasket material. DO NOT NOT SAND! new gasket, new pump. when installing the pump start with the bolts (and nut) in the middle, and work to the outside. If you miss any pump bolts, even the nut in the middle, the pump will leak. Never forget you are working with aluminum. When tightening the timing belt, make sure it is good and tight, but not over tight, and triple check timing marks. Installation is the reverse of removal.