What size are they? Imperial size I used a M8 bolt and now it's stuck (only partly in), the threaded insert in the bumper is rotating instead of the bolt.



I will have to cut off the head of the bolt to remove the mudflap. Then after that I'm not sure. Probably need someone to weld the threaded insert to the bumper so the remains of the bolt can be removed using mole grips.

Sigh.

Maurice

I have sometimes the same plroblem with inserts of a fence.
Cut off the bolt and Use a drill with the outside diameter of the hole. Stage two of your drill and try to wedge the insert with a lot pressure to drill it out.
If this dosen´t work grind the outside of the insert away. So you can put in a new insert 

Regards Nils

The (alternating/subsequent) application of strong heat (torch/welding current) and/or cold (water/spraycan)*could* make either component expand or shrink, and change the dynamics....
Rustdissolver isn't heatresistant, sadly, but copperspray might still do the penetrating trick....

Zitat von: Bär am 11.Februar 2022 20:47:11

If this dosen´t work grind the outside of the insert away. So you can put in a new insert

Yes, that's a good idea. There's a hole at each end of the bumper, the remains of the insert will eventually fall out. Actually I may be able to pull it out with a bent coat hanger, that would certainly be safer.

Another problem resolved

Thanks
Maurice

Zitat von: Bär am 11.Februar 2022 20:47:11

If this dosen´t work grind the outside of the insert away. So you can put in a new insert

Excellent advice. I cut off the bolt head, manually filed down the edge of the insert, then one quick thump with a hammer and the whole thing popped into the bumper.



Then a bit of "fishing" with an old wire coat hanger to remove it. New insert and 5/16" UNC bolt ordered 

Maurice