If I get a tow bar which is missing the Pins and Clips, or the Pins are rusted, I make my own from what I can obtain at a good hardware or one of the large “box” hardware stores.
I purchase J-Bolts/Anchor Bolts from the hardware or builder’s section for these. When Neva and I went recently to buy one for this article, we found them in the nail section of a large “box store” in the hardware department. Buy J-Bolts which are galvanized to prevent rusting. (2 of these cost me, including tax, $2.32)
Anchor Bolts are used for slab foundation buildings. When the cement is still wet, these are inserted with the bent piece down. The threads remain showing. When the cement has dried, the sill plates and other plates will be bolted to these J-Bolts.
Buy J-Bolts which are longer than what you need. I purchased Bolts that are just shy of 8-1/4th inches in length. This way, the threads can be removed so that you can drill the Holes for the Hitch Pin Clips–which also can be purchased at these same stores. A pair of Clips cost me $1.30, including tax.
The Hitch Pin Clips which I use are 5/32nds of an inch in diameter by 2-15/16ths inches long (measure on the straight side) and are bright plated.
Each Bolt comes with a large washer and nut. These can be put with your other saved-for-that-obscure-project parts.