how to remove seized rounded allen bolt?

[205man]

as some you know my water pump gave up, so my mate came round to help me pull car apart but we hit a snag.

we cant get the idle pulley/bracket off, because the bottom allen key bolt is completely round inside and pretty sized, and the one above seem to be also seized but the head seems ok i just need better allen socket before i risk the head on that going.

so an ideas on how to remove rounded allen bolt, ive seen load of ideas on the net, but thought id ask what has worked for you.

the strange thing is the last time this was taken apart was 4 years ago when main dealer fitted new cam belt etc ???????

cheers

 

[towcestervag]

i use irwin extractors
they cut into the outer part of the bolt and work very well

 

[cerips]

Irwin extractors or hammer in a Torx or XZN bit.

 

[Blue_Thunder]

+1 for the Irwin Bolt Grips. Excellent bit of kit!

 

[Broken Byzan]

xzn and a hammer here, not failed yet.

 

[Todd1983]

Hammer in a Torx

 

[PAULF]

+1 for the Torx bit, or I have a stud remover that sometimes works, or pipe stilsons.

 

[aragorn]

Or weld on a standard bolt.

 

[Steve_D]

I used an angle grinder to make a standard socket fit on... came off a treat and replaced the bold.

That was on the rear caliper carrier bolt

 

[ctd]

torx bit for me every time