hi i am planning on stripping my old trx 2.5 down an re-building it as a spare engine the cooling head is pretty knackerd any way so i was planning on changing it but the problem is when i was removing the head screws the end of the allen key snapped in one of the bolts so how the hell do i remove the bolt i was thinking of cutting it off with a hacksaw and then removing the bolt. or is there a better way?