Spinning bumper bolts and other scavenged items

Got a better front bumper.  2 bolts are loosening, 2 are spinning.   Can't get vice grips to stay on the head.   How do I get them to stop spinning and start loosening?

Pic is ready of stuff picked off a truck the dude wants to strip as much as possible.  $80.  Some of this is for Jonathan's truck as well.   I'll probably go back in a couple weeks for the heater box and maybe the wagon wheels.  All 4 with caps.  Need blasting but price is reasonable.  

Let me know if anyone needs parts.  Still a lot there.   No bed, cab is shot.  Seat isn't bad but is ripped (red).  Doors, inner panels with chrome.  Plastic is scaly but feels solid enough.  Hard dash part is still pretty good.  Dash pad is gone.  He still has the doors.  Core support looks straight and solid.  4x4 and all he wants is engine.  Both axles still there.

once they spin i give up on them. they become sacrificial. i use a right-angle grinder to grind away the head but be very careful not to get the bumper. grind an x across the center as far as you can to get as deep as possible that allows the rest to be ground with a little more control. maybe just my imagination but I do it.

Yes, once they spin you are going to have to sacrifice them.  I don't have a nut-splitter but some have used them successfully on this problem.  I've used heat and PB Blaster, repeatedly, to get the nut to turn.  But it usually ruins the bolt.

mat in tn wrote

once they spin i give up on them. they become sacrificial.

Yup. Up here in the land of rust, it is very rare that the bumper carriage bolts can be removed by normal means. I drill them out. Might have to clamp the bolt with Vicegrips regardless, but I go through them pretty quickly with a drill. They're just regular steel bolts with thin stainless caps on them.

Gary Lewis wrote

Yes, once they spin you are going to have to sacrifice them.  I don't have a nut-splitter but some have used them successfully on this problem.  I've used heat and PB Blaster, repeatedly, to get the nut to turn.  But it usually ruins the bolt.

I use the nut splitter
When in the field and no battery powered tools this is the go to tool
Dave ----