I have a problem with a broken valve cover bolt that I thought was resolved. It was not leaking when I only had the car idling in the driveway. Now that I'm able to use it for running errands and fix stuff, it started leaking again. It's in there pretty good and it looks like the threads are bad. I'm thinking about just drilling it out with the next size carbide bit and re threading it to the next size bolt. What do you guys think, anyone try it before?
Broken valve cover bolt.
- Thread starter chrger1967
- Start date
6PKRTSE
Well-Known Member
I have had to drill some out and helicoil repair them before on different cars. Any more, I usually stud mine with 1/4-20 x 1/4-28 studs and use 1/4-28 nuts to tighten them down. No more stripped threads on 50+ year old heads, you can get more torque on them, no more leaks.
Jeff K
Active Member
I agree, use a left hand drill. Sometimes the drill will get most of the way through the broken bolt, then the old threads will give way and the bolt will start to rotate. If that happens a left hand drill will back the bolt out, a right hand drill will tighten it further. If you have a blind hole the bolt can bottom out, stop turning, and snap the drill in two. A left hand drill alleviates that risk.
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If there is enough bolt exposed to grab it try and induction heater.
They work wonders
They work wonders
There was nothing, it was below and it looks like someone tried to drill it out already and screwed up the threads. I think the only way to do it is to drill it out and my try renewing the threads.
If I can get that out, I would be happy with a stud as long as it stops leaking.
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