I have a 1066 IH with 20.8x38 duals. The tractor is a southern tractor with the extra long axles and they have spent most of their life set on 38" rows. I recently took the duals off and moved the hubs in, for 30" row spacing and tightened the large U-bolts on the hubs down extremely tight with a 3/4 in socket/breaker bar and 4' cheater bar. I checked it after a day of use row crop cultivating and it was getting a little loose so I tightened it back, but it keeps working back loose. Now the hub and wheel/tire have slid out to the original spot. There's a lot of pressure on the hub when the tractor pivots on the tire. What can I do to make it tighter and stay in place?