Kubota HST Input Shaft Splines Stripped

[Hysyde]

I wouldn't classify rocking the hydro back and forth as abuse to the input shaft of the hydro unit. The engine isn't changing rpm's and the shaft is running at a constant speed. The back and forth all takes place within the hydro unit. In this case the hydro isn't broken. The input shaft is.

I was thinking I guess more along the lines of loading and unloading the engine fairly quickly, and thus the input shaft. The back and forth I suppose isn't as relevant (although probably not great for the hydro).

What forces would otherwise cause this part to wear? It's bee na few years since it's seen snow. I tried to avoid ramming it into banks (to avoid twisting up the front implement arms more than anything) but pushing slowly into banks would definitely load the hydro/engine.

 

[Hysyde]

A strong cheap fix may be to saw cut item 40 (flex joint) perpendicular to the cross bolt so it can be squeezed to the shaft. Then, use a clamp collar next to the bolt to squeeze the flex joint to the shaft. You would have to measure the OD where the cross bolt goes through. Here are the clamp collars:

McMaster-Carr

Possibly an option, but as I havn't heard back, it looks like the machinist is going to try and re-spline the shaft. Not sure what's that's going to cost in shop hours, but we'll see how it goes I guess.

 

[Hysyde]

Could you drill another hole the same size and use 2 bolts?

I just worried about weakening the cross section of the shaft. If it snaps, I'm definitely into a new one.

I'm willing to invest the machine at this point. I'm not going to find an equivalent without spending a lot more and it's difficult to find these machines (and the newer models) that haven't seen a lot of tough hours from landscape crews. Decent deals do come up at auction with some city owned/leased ones, but I have other priorities right now.

 

[pmsmechanic]

What forces would otherwise cause this part to wear? It's been a few years since it's seen snow. I tried to avoid ramming it into banks (to avoid twisting up the front implement arms more than anything) but pushing slowly into banks would definitely load the hydro/engine.

My guess is that there is some fore aft movement due to the rubber engine mounts. That along with rust in the splines wears them out. I've also seen the same issue on a clutch disc in a pickup truck.

This reminds me I should really check the splines on my front driveshaft on my 4410. A bit of new grease in there wouldn't hurt.

 

[Hysyde]

All patched up and back to work. Had the shaft repaired and a new coupler put in.