Center spindle nut will not stay tight

[Chuck E.]

Question about a 10 year old Toro commercial zero turn with a 62"groundskeeper deck. The center spindle bolt loosened up threw and destroyed the belt. I removed the spindle and found the top seal was destroyed but everything else seemed O.K. outside of the splines were worn so there was some slop on the pulleys to the shaft.

I cleaned up and reassembled the spindle with new seals and installed. Tightened the nut and used permanent locktite on the threads. Two passes in the yard and the spindle was loose again. Re-tightened and peaned the top of the shaft to secure the bolt. It still loostened up.

Can someone tell me what I did wrong. There was no lockwasher or castellated nut. I ordered a complete spindle assembly and don't want the same problem with the new parts. How much can I torque down on the nut without damaging the bearings?

Thanks, any input will be greatly appreciated.
Chuck E.

 

[mechanic mark]

https://www.toro.com/en-us/customer...ferences/Service Manuals/service-manuals.aspx

 

[Carscw]

I tighten them till I know they won't come loose.
You are not going to hurt the bearings.
There is a spacer in between the lower and upper bearings.

 

[bertsmobile1]

I tighten them till I know they won't come loose.
You are not going to hurt the bearings.
There is a spacer in between the lower and upper bearings.

And they get very hot.
Heat loosens loktite so if you locktite use the high temperature variant.

 

[Carscw]

And they get very hot. Heat loosens loktite so if you locktite use the high temperature variant.

If the shaft gets very hot then there are problems.
I feel my pulleys 3 or 4 times a day to make sure they are not hot.
If they are hot I change the bearings right then.

 

[mechanic mark]

Try a self locking nut.