I'm installing a RE 3.5" lift with new leafs. One of the front bolts just keeps spinning though. I searched and found out you can cut the welded area underneath it so you can get to the nut on the other side. I did that but the nut isn't broke. It's still welded on. All that's left is the bolt with the metal sleeve around it. I cut everyhting else away. So why won't this bolt come out?????