JD 420C Hydraulic Pump Drive Question

[dmlinton]

My 1957 420C has the hydraulic pump located below the radiator. It is driven, apparently, by a floating shaft (that looks like a PTO stub shaft) that is driven by a female part bolted to the crank shaft pulley.

This "floating" shaft has taken to floating so far South (toward the engine) that it comes out of the female part on the hydraulic pump. There is nothing obviously missing but it seems stange that the drive would be designed in this manner. In other words, it seem to me that sometihng has to be missing. There is no sign of any sort of locking mechanism to keep the stub shaft from wandering.

Can anyone shed some light on this?

Thanks in advance.

Edit: I finally remembered that I have a 420 service manual. It says the 420C only had one hydraulic pump and the one on mine ain't it. I suspect that the hydraulic pump I have is associated with the No. 90 loader I have (like the one below) - not the tractor.

[whiteclipse16]

Dennis, your pump sounds somewhat like the one on my 440. I have a splined female piece that bolts to my crank pulley and then a small stub shaft up to the pump. My parts book shows a snap ring going around the stub shaft to keep the stub shaft from going back into the coupler bolted to the crank pulley.
You might need to take your stub shaft out and have a groove cut in it for a snap ring.

[dmlinton]

Thanks, Ben! A snap ring would make perfect sense. Is the parts book you refer to for your tractor or for the loader on it?

[Lavoy]

Something is odd, the splined shaft should be oversize in the middle so it shoulders against the drive on the crank, and the coupler. It is possible someone has made up a shaft and did not provide for this.
Lavoy

[dmlinton]

Something is odd, the splined shaft should be oversize in the middle so it shoulders against the drive on the crank, and the coupler. It is possible someone has made up a shaft and did not provide for this.
Lavoy

Damn you're good, Lavoy! That's it! I went out and looked at the shaft again and it looks like some (1/2 inch or better) of the oversize spline appears to be gone on the end that goes to the engine - as in worn off with almost lathe-like precision. The part that bolts to the crank pulley does not show much wear.

I also found when I took the stub shaft right out that the coupling that goes on the pump input shaft also just floats.

I wonder if someone has put that shaft in backwards? I will get some measurements on the position and length of the oversize part and overall length of the shaft.

[dmlinton]

Here are the hydraulic pump drive parts laid out left to right (pump to engine). The shaft is 3 inches long with 1 inch from pump end to oversized spline, oversized spline length about 1/2 inch leaving 1 1/2 inches on the engine end. Is it possible that the shaft was instaled wrong end around last time?