I've replaced my threaded rod about three times now. It's almost become an annual event in spite of cleaning the grit and oiling the threaded rod with every stage.
There may already be a thread on this if you search. I'm going from memory. Here are some of the key steps.
1. Peel up the foam pad from the base plate that the bowl rests on. Chances are, you will destroy the foam pad in doing so. Have a replacement ready before you start so you don't have any down time. You can get a replacement pad from any Inland or Ameritool dealer. It's the same foam pad that is used as cushion beneath flat lap sanding disks. A cheaper alternative is to use self-adhesive cork from a hobby or craft shop.
2. Look for 4 bolts located directly above the springs. The bolt heads are located in depressions and may be beneath a dollop of silicone calking. Do what you need to do to get the bolts off.
3. From the underside, look for the two silver braces that hold the motor to the baseplate that the bowl rests on. Remove the bolts to release the motor braces from the baseplate.
4. Look for 4 bolts that mount the motor to the baseplate that the bowl rests on. Remove the bolts to release the motor from the baseplate. Same as before, the bolt heads are located in depressions and may be beneath a dollop of silicone calking. Do what you need to do to get the bolts off.
5. The baseplate that the bowl rests on should now be free and you should have access to the threaded rod.
6. Replace the threaded rod, washers and bolts as necessary.
7. Reverse Step 4, Step 3 then Step 2.
8. Use silicone calking to seal the bolts and around the threaded rod. Replace the foam cushion.
Hopefully I didn't forget anything major. Let us know how you make out. If you get stuck, there are a number of UV-10 users that have been through this.
Darryl.