Bumper/undertray bolt snapped. How to remove?

[Meds]

Hey guys. I thought I'd tackle this little issue.

At the rear where the bumper screws up to the underside of the car, there's an nut/screw/bolt that threads up into the battery compartment.
It has snapped, leaving the bolt stuck inside the battery compartment thread, with nothing to grip to try and twist out.

Any ideas?

 

[bigwinn]

Can you drill it out and re tap it?

 

[Meds]

I'm unsure, as it screws into the underside of the plastic battery compartment.
There must be some sort of metal thread insert, in there, right ?
I think I need to jack the rear up to get a better look.

 

[bigwinn]

Yeah that right- there is a brass threaded insert with splines that prevent it from turning in the plastic

 

[Meds]

Got it, thanks.
I'll need to tackle this carefully then as ruining the plastic around the splined insert could mean a new battery compartment.
Actually, some JB Weld might help me to secure a new threaded insert if I need to install a new one.

 

[Meds]

OK fixed..
Kind of..
Overnight soaking with penetrating fluid, banging with a hammer and gripping what was left of the screw with various pliers and molegrips, failed.

I ended up using a self tapping screw to create a new thread into the plastic battery tray, and then using a proper 8mm undertray screw to secure it all.
Not ideal but sorted, and if I find an opportunity to get underneath again I'll look to try and drill out the brass insert and go from there..

 

[enuff_zed]

I'll look to try and drill out the brass insert and go from there..

I tried that with the similar insert that holds the battery clamp bolt. But the heat generated from trying to drill out the snapped bolt melted the plastic and the brass insert span. I ended up taking it out and using Araldite to set a stainless nut in it's place.

 

[Meds]

Yes, i can see this task ending up the same way..
I'll probably leave as is, the new thread is solid and should be fine unless I start disturbing it often, which I have no need to do unless the rear bumper needs to come off.

Thanks for the help.