Twenty Water pump rebuild

On my wide 20 project the water pump shaft is very pitted where the packing would seal, thus it leaks a river. I had extra water pump for parts and the shaft looked good so I disassembled it. Every thing came apart easily and I did use a gear puller for the drive gear. I was happy with the appearance of the shaft as it looked to be in good shape at first glance. I chucked it up in the lathe to polish it and quickly found it bent, not just in one spot but especially at the end where the governor would ride. I am amazed this could have run in a machine, The gear looked to be in good shape, I considered something went through the gears but no signs of trouble there. So what I have is a good sample to get dimension for a new shaft. The strange thing is the largest OD is .862, that would make it very close to a 22MM shaft. I have a piece of .875 shaft and it will not fit in the pump housing bushings so I am quite sure its metric. Is this possible ? Did cat do it like this ?

[attachment=59160]IMG_3998.jpg[/attachment][attachment=59161]IMG_3999.jpg[/attachment]

If the shaft is a genuine Cat part shouldn't it have a part number on it, possibly someone made a new shaft for it years ago?

I bought an NOS shaft several years ago and no part number on it. There was a part number on the tag. TAP had two in stock when I bought mine. Florin bought TAP's stock so check with them to see if they still have one.
Thanks
Ken

It might be a custom piece Steve, and they reamed until the desired fit was achieved. If you rebuild, you could change the shaft and bushings back to a regular size

I was able to measure the shaft in the tractor and its the same so i am thinking its metric. New shaft soon to be made.

The numbers are a little hard to read on my print but. Shaft dia. .8626-08620 ground. overall length 15.5, 2 #13 woodruff keyways. The two holes for the taper pins are #19 bits with the holes reamed for the taper pins at assembly. My early parts book list the shaft as 7/8" dia and 15 5/8" long. The bushings are 1.250 long, the taper is 30 degrees, od 1.251 - 1.252, in .853-.855. inside graphited and ID mush be concentric with od within .002 total indicator movement.