Any broken stud Drill-out and extraction tips?

[DanH]

I attempted to drill out and extract a broken exhaust stud from my M30 head, but apparently i must be slightly off center since it will not turn out (The extractor must be catching on the heads threads.) I successfully removed the other broken stud with a penetrating oil, a torch and vise grips, since it was protruding enough to get a grip on it.

The stud is 8mm OD and I have a 6mm+/- hole drilled through it, the stud was snapped off about 1mm below the gasket surface. So, now it is nothing more than a thin hollow cylinder stuck in the hole. How can i get this out? Right now I'm thinking its about time for a machine shop to just drill out the remainder and put in a heli-coil, but I'd like to try any other DIY methods first...

[Jeff N.]

Soak it in PBblaster and try a varity of removers. I've had better luck with the square type removers vs. the spiral type removers (both available at sears).

Short of that, I'm not sure what other wisdom I can offer. Never fun when this happens.

[DanH]

Thanks for the tip. Those square removers might be easier to keep from binding on the head threads(I can't tell if i've drilled into them or not though.) I'll have to look for a set.

I only have cheap spiral removers and the expensive craftsman drill out/extractor all-in-one bits. Neither has worked.

Now that I have a hole all the way through the pbblaster ought to attack from both ends of the stud...

[632 Regal]

if you have it close enough to see the threads you can probably use one of them real small chisels to chip the stud threads away from the head, it tedious work but I have done it several times.

[Bill R.]

square ones versus the spiral ones... the best results i get are with the snap on blue point spiral extractors which have much finer spirals and many more of them so they contact a large amount of surface area, There are some cheaper variations available nowdays along with left hand drill bits to make it easier to get them out. Since its an aluminum head sometimes it helps to heat the area around the broken stud with a propane or acetlyene torch, the aluminum will expand more than the steel stud and then once its warmed up good you spray the center of the drilled out stud with wd40 to cool the stud down shrinking it while leaving the head hot.. then you quickly tap in your extractor and hopefully screw it out.. This one at this link is similar to the snap on only the snap ons come with spiral flutes or straight flute... I have both and the spiral fine ones work best for me...If you already have the head out and easy to get at then i would just go buy a helicoil kit and drill and tap it and be done with it.. the kit is usually around 25 bucks with the helicoil tap,drill, installing tool and enough helicoil inserts to last awhile. Not difficult to do.

Soak it in PBblaster and try a varity of removers. I've had better luck with the square type removers vs. the spiral type removers (both available at sears).

Short of that, I'm not sure what other wisdom I can offer. Never fun when this happens.

[western99]

the center of the broken stud. If you do it proberly, the stud will start to turn out without making further damage. I did this with my ABS sensor and it worked like a charm. Clean and easy. Just make sure that you are center.

Brian

[Jeff N.]

...or better yet .. quit snapping of studs!

square ones versus the spiral ones... the best results i get are with the snap on blue point spiral extractors which have much finer spirals and many more of them so they contact a large amount of surface area, There are some cheaper variations available nowdays along with left hand drill bits to make it easier to get them out. Since its an aluminum head sometimes it helps to heat the area around the broken stud with a propane or acetlyene torch, the aluminum will expand more than the steel stud and then once its warmed up good you spray the center of the drilled out stud with wd40 to cool the stud down shrinking it while leaving the head hot.. then you quickly tap in your extractor and hopefully screw it out.. This one at this link is similar to the snap on only the snap ons come with spiral flutes or straight flute... I have both and the spiral fine ones work best for me...If you already have the head out and easy to get at then i would just go buy a helicoil kit and drill and tap it and be done with it.. the kit is usually around 25 bucks with the helicoil tap,drill, installing tool and enough helicoil inserts to last awhile. Not difficult to do.