My rear wheel locked up!

I have a 1984 Club Car electric that I bought used 11 years ago.
I use it every day winter and summer.
We heat our house with an outdoor wood furnace.
I even keep the furnace going all summer, just to heat the hot water.
I cut wagon loads of wood and use the golf cart to pull them to the furnace.

I install tire chains in winter otherwise the tires just spin when we get freezing rain.
There really isn't enough clearance between the tire and the suspension,
so last fall I installed lug spacers that I bought on eBay.
They give an additional 1.5 inches of clearance.

My driver's side rear tire locked up today and started dragging.
I found that 3 of the lug bolts were missing completely,
and the fourth was disconnected from the spindle.
The lug bolt just rotates freely.
The lug nuts were still connected to the spacers.

Do I need a new spindle or what?