1985 California RZ350
I decided that on things like water pumps and oil pumps I would replace all the small parts I could as they are so critical to the running of the bike. Below is a shot of the right hand side casing once I cleaned it up and gave it a new coating of casing paint.
The water pump is rebuilt from both sides of the casing and has a gear that meshes with the crankshaft gear when the casing is reinstalled..
Above are some of the parts I replaced from the rusty water pump that was disassembled. At a minimum I would recommend a new oil seal and a new gasket cover.
The first step is to flip the casing over as the seal and bearing go in from the inside. Make sure the recess where they go is clean and ready.
Take the seal out of the packaging and have a careful look at each face. One of them will say "water side". This face needs to face out towards the rotating part of the water pump.
Push it fully down in the hole. You can use a socket of a similar diameter to ease it down into the casing. Typically just some pushing will get it in place and you won't need to try tapping the socket in place.
Follow the oil seal with the bearing. My bearing came from the supplier already greased up so I left it that way. The bearing can be tapped home with a socket.
Flip the casing back over and put some grease either on the lip of the oil seal or on the shaft of the impellor. Slide it through the hole and flip the casing back over to work on the inside.
Take the small dowel and place it through the impellor shaft. If the hole can't line up with the dowel then the bearing is not far enough in and will need to be seated deeper into the casing.
The plastic drive gear has a slot to take the dowel and locate it on the shaft.
With the gear in place it is followed by a single washer....
....and a circlip to hold it all in place.
Flip the casing over for the last time. Make sure the impellor area is clean and then fit a new gasket followed by the galvanized cover plate.
The cover plate is held in place by 5 Phillips head screws which are a pain to get out in the future. I changed these for stainless Allen head bolts instead as they are far easier to remove in the future. This completes the water pump rebuild.