Water Pump w/Cast Pulley

I hope you can help me. I have an Oliver 770 tractor gas engine. The water pump leaks like a sieve and needs replacement.

Working with a local ag dealer, I purchased a new water pump that otherwise fits, however, after removing the old pump from the tractor, I realized the old pump has a casting with the pulley and fan mount flange as a single piece. The new pump had a plain flange to mount the fan blade but no pulley. All the Oliver pumps I could find also have a plain flange and require a separate pulley. I returned the new pump to the ag dealer who help me with a pulley and took the pump back. At this point, I can either repurchase the water pump and try to source the proper pulley, or try to rebuild the old pump or hopefully have you provide me with a solution.

Attached are pictures of the tractor ID plate, the hub and pump and a drawing of the required geometry of the pump/pulley. Tractor model looks like 37-1946 and serial # 134-729-721.

The water pump has 5 flat head screws attaching the back plate, with one screw small than the other 4. Pump has a casting # 190360

I have pics and a pretty good drawing of what I need - not sure if I can attach.












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The new pump you purchased is for an older 770. Going by memory here but I think there were at least 3 different 770 water pumps. Do you have access to a press? You need to get the right pump or rebuild yours. Questions? My e-mail should be open. j.

Thanks J

I did not include a picture of the pulley I have. The old pump has a .627 dia shaft and the hub presses on pretty hard. DO you now if the other pumps have a similar shaft dia? If so, its starting to look like my best option is to buy back the pump I had, remove the new hub and press on the old one. What do you think?

If you would like to have your pump rebuilt or purchase a kit, send me an email.

Try Kellog Automotive in Az, Online catalog and you can buy the parts or he can rebuild it for you. I rebuilt my 1550 pump that way. The hard part was getting the pulley off. I can post pictures of my setup if you want.

I'd just get the new pump you had, compare the shafts and if all else is the same, press the flange off and press the pulley on. Yes they can be a hard press.

You have a later water pump. The new pump you received may have a different distance from the center of the crankshaft to the center of the water pump. What is the part number/casting number for the pump you purchased?

Thanks to all for your input. I'm going to go ahead and get the pump I originally bought and install the cast hub on it. I just want to be as sure as I can that I will get a good press. Other concern is getting the pulley to line up with the crank pulley and generator. This way I can get that perfect. Plus, for the cost of the pump I can avoid the potential can of worms involved with rebuilding, which looks to me like a bargain.

Thanks again for your interest and input. Think I will be spending more time at this site..