Go buy the bolt, Just a buck or two and you can easily find them at Lowes or Home Depot with the specs provided. That way your not pulling the wheels off. I bought a bolt when my fan imploded taking everything with it a couple of years ago. Worked like a champ.
Could not find 14mm x 1.5 locally (Lowes, Home Depot, Ace, Rural King, Fastenal) I did find out that for many years, say, ’92 through ’08 Mercedes used a lug bolt that will work. So I went to the junkyard. The bolts were gone from the Mercedes but I noticed lug bolts screwed into a Volvo wheel and pulled one on a hunch. Worked fine, free. No idea what year Volvo but if you find a correct sized one on ebay the auction might list the years it fits. Same for the Mercedes. Searching eBay, it appears that a number of makes used the 14mm x1.5mm lug bolt. BTW, the threads need to go into the fan just under ½ inch on my ’81 GL500.