This is a pretty inexpensive way to fix the broken spare tire cover knobs.
It ended up costing $17.00.
Remove the tire cover.
Remove the four square plastic nuts.
Place a bolt with a nut and washer through the square nut and then place another washer and nut on the bolt.
The distance of how far the thread goes out is adjustable.
Then clip the square nuts back into place.
Replace the cover and screw down with new knobs.
It is that simple