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Broken Bolt

I recently changed the valve cover gasket on my 1968 chevy C30 truck. But, when tightening down the bolts one of them broke off at the head. I was looking at bolt extractors to remove the broken bit, but is this something that a shade tree mechanic like myself should be doing? Or should I take this to a machinist? The 292 inline 6 is old and needs a lot of work anyway. Maybe I should just leave it alone and monitor the oil level?



Yes it can be done…The easiest way might be to drill it out…then retap the hole with a larger bolt.

How much is it leaking? Any more than a little seepage will make one side of your engine oily and dirty. A “regular” auto mechanic at a good shop can deal with a broken bolt. If you DIY and you’ve never done drill and tap before then practice on a piece of scrap, not your cylinder head.

If you are willing to invest in some cutting tools give it a try. The first thing I would try is a left-twist drill bit,it may grab it and spin it right out.

The problem with any easy-out type solution is that these bolts are typically very small and you don’t have much metal to work with.

I would not try to drill and retap the hole. There is a distinct possibility of drilling into the water passages. I know because it happened to me many years ago on a Chrysler 400 V8.

Yup that is a possibility…So you have to make sure you only drill down as deep as the hole is. Put the drill bit in one of the other holes and put a piece of tape marking the depth. Then when you drill the bolt that broke off…NEVER drill pass the tape and you’re assured of NOT drilling into anything you don’t want to.