what the hell is up with these bolts

[Andy03]

Taking my rear beam off for refurb and repaint however I'm a little stumped by the bolts that hold the beam mounts onto the chassis, they're the one that has the head of the bolts covered by some metal thingy and are located under the rear passenger bench seat, obviously after 12 years the bolt threads are quite corroded so I can loosen them off but there is no way of holding the heads still while I go at the nuts on the under side. I'm tempted just to cut the heads off with a grinder but I'm also concerned about the ability of replacements and how I would go about redoing the bolts up on refit.
Does anyone have any suggestions?

 

[Andy03]

Forgot to add the bolts are round and have nothing to get any sort of tool on it

 

[Tony Hunter]

This is another wonderful Renault design. When we built the race car, we just cut them off and replaced them with long bolts. And yes it might take two people to do this.

 

[Andy03]

Hi Tony I'm thinking that I'll do the same. Good to hear someone has already done so