Car Mechanics (UK)
Removing rounded bolts
Q On attempting to change the cambelt on my VW Golf GTI, only two crank pulley bolts came out easily – the other four were completely rounded. It looks like the mechanic used ‘red’ thread lock on its first change. I have tried using screw extractors, but they just chewed into the Allen key holes even more. I obviously can’t remove the centre bolt as the Golf crank isn’t key-wayed, so I’m hoping you may have another suggestion.
A Well, you may be pleased to know that this problem is quite common. It’s something I have come across regularly and although a hammer and chisel used to tap the bolt round from the head may work, a much easier way is to use a multi-splined bit tapped into the centre of the rounded Allen bolt. I have always found this to have sufficient grip to then remove the bolt. This action of banging the bit into the bolt will also assist in loosening the thread, making the chance of success higher.