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I am having an issue with the water pump on my 1937 120. When the pump is attached to the block, the back cover is being pushed into the shaft, thus not allowing the pump to turn freely. The pump will turn quite freely when removed from the block. I have three options on how to handle this, but wanted to see if any of you have had this problem before and maybe have a different solution. My options as I see them are 1) replace the gasket between the back plate of the pump and the body of the pump with something thicker to keep the back plate from pressing against the shaft; 2) customize a gasket going between the back plate and the block with an opening at the point where the shaft would be pressed against the back plate so that it would not be pressed by the installation or 3) grind down the shaft at the rear about 1/32" or enough to keep the shaft from pressing into the back plate when the pump is installed. Does anyone have any other bright ideas? Thanks.

The shaft is pressed into the impeller so that it is flush, if it is too far forward or back it will hit of the clearance will be too big decreasing pump efficiency.

I'm wondering if you just disassembled or rebuilt the pump??
If it is assembled correctly there is no need for the remedies you propose

Thanks so much for the information, Fred. Since I do see about 1/32" of the shaft at the back of the impeller, then I am assuming that when it was rebuilt, the shaft was not installed according to the proper tolerances. What I think I will do is take it to the machine shop here and see if they can get the shaft flush with the impeller as you say it should be. If they can, then I'll see if that solves the problem. I'll let you know what happens after that. Again, thanks for the help.

Further reflection: With hte shaft flush with the back of the impeller the hub should be almost up against the front of the casting. There should be a thin (.025" approx) phenolic washer in between.

Report on your findings please.