Product review (5 stars): Falls apart quickly - but we have a work-around!!!
Thank you to the reviewer who solved this problem! We are so tired of investing in these. Since the wheels and assembly housing outlast the plastic "screws," we are thrilled to have a way to make these almost indestructible.

Here, with parts numbers from Lowes, is all you need:

For each wheel assembly, buy 2 of these (we went with stainless steel):

Hex bolts
1/4-20 x 3/4" long
Lowes #396434

Flat Washer
1/4"
Lowes #311726

Stop Nut
1/4"
Lowes #114172

Thanks again to the couple who figured this out!