MM GB water pump issues


New User
Hey guys I am trying to repair my water pump on my GB it was leaking coolant into the oil so I disassembled the front end obtained correct seals from welters all of that would be fine and dandy except for when I took the impeller off the end of its shaft I noticed it has made contact with the water pump housing. The book says I should have a nominal amount of end play in the shaft where as I have close to 1/4 inch enough where the lip seal backs away from the carbide seal surface I am assuming this is what is causing water to leak into the engine oil. So I guess my question is what controls the end play in the ignition drive shaft I can’t tell from the book? Also at the opposite end of the water pump shaft is where my hydraulic pump is driven. As always any help is greatly appreciated
Depends what you have! The gas, LP tractors and the Diesel tractors have different pumps. In no case is there a LIP seal used for sealing water. Don't know what book you have? If it is a Diesel you meed a MM shop manual. the impeller has to be pressed on to specs. And it has to be mounted with shims to have the certain amount of end play.
I just reread your post. and you mentioned ignition so I am guessing it is gas or LP. You said you disassembled,
did you take the front of the timing case off? If you did that is where the lip seal goes behind that hub to seal out oil from the crankcase, And you need to take that hub and machine the front of that hub FLAT and smooth so you get a good surface for the carbon water seal to mate to. While you have that all apart put a new bushing in the hub. After you get that all back together the impeller with seal in it screws on the shaft LH thread till it bottoms out then back off to the closest hole to insert the the pin. Having said all of that, how are the threads on your shaft and impeller??? Is it stripped and that is why it is moving so far and rubbing on the housing??
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