Im getting ready to sand down and prevent anymore rust under my 1991 Cherokee. So far im going to take off the skid plates starting with the gas tank one that is starting to flake and need to get to it now before it turns to dust "Still solid" I manage to take one bolt off but it broke off and it started to brake thinking it was going to come off then it snaped. I already sprade day before and same day with WD-40 and PB Blaster. I also checked the broken bolt and it sort of sticks out to get to. But have to remove the skid plate first. The bolts bolt into the frame too. So far havnt temped the other 3 of 4 bolts.

 

Try applying heat to the bolt. Just be extremely careful around the tank.