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Use an easy out as a last resort. If the bolt is stuck in there hard enough to actually break the bolt, then the easy out will break long before the bolt loosens. Then you're really screwed; you can't drill out and easy out (the metal is too hard). Easy outs are most useful when the bolt was broken from an external smack, so that it is no tighter in the hole than it usually is.
A left hand drill would be my first choice. Our favorite tool store has them. https://www.harborfreight.com/left-h...-pc-61686.html But otherwise, as millball points out, they are not common. I was in my local Home Depot looking for them, and one of the young ladies now working there asked if she could help. I asked if they had left-hand drill bits, and I got the look that said "yes, I'm a women, but you don't have to prank me." I assured her left-hand drill bits were a real thing, but I'm not sure she believed me. (and Home Depot doesn't carry them.)
Most machine tool supply houses will have left hand bits, or they can get them. I'd be looking for American, or German made drills.
Auto bolts are usually at least grade 5 (or metric equivalent), sometimes harder, and it takes true high speed steel to drill them.
Easy-outs are best used after the bolt has been drilled out to a thin shell. It is indeed easy to break them, but experience and proper technique
help to minimize that happening.
can you take a pic of what's left in the head? are you trying to get the remaining bolt piece out and also save the threads?
i've had to drill out a couple of broken exhaust manifold studs on my 22re when i rebuilt. i didn't try saving the threads, though, and just helicoiled them.
i also had to drill a broken head bolt on one head for my 3vze when putting on new heads. the head snapped off and had to drill down past the shoulder to get the head to slide up and off. THAT SUCKED!
I my view, it is worth trying to save the threads if you can. Using a larger bolt is out of the question here. Inserting a helicoil really requires a very precisely drilled hole -- using a mill, or at least a drill press. If you hand-drill the hole for the helicoil, you'll end up with a loose fit, and if you are unlucky enough you may pull the helicoil out. (My truck had a cam bearing bolt pull out, and when I got it free I found a helicoil hanging on the end of the bolt.) Once you pull the helicoil out you're really out of options, as you have already drilled out the metal.
Of course, sometimes you just have to make the best of a bad situation.
good points. my situation worked out well on the exhaust, though. slow drill...steady hand. i was able to stick with the oem size thread, too. fortunately, the tensioner pulley's not a high torque situation. but, then neither is a cam bearing, is it?
if the remaining bolt piece is recessed, i'd be surprised if it could be drilled out straight enough not to hit threads. i had a clamping bolt break off in the steering knuckle of my subaru when trying to change out a ball joint. the clamping bolt threads in to one side of the knuckle. i should have ripped the whole assembly apart and drilled it out on a press to begin with, but that's a lot labor i wanted to avoid. so, i tried by hand. pfffth! i couldn't get it to drill straight through the bolt was so hard. wound up having to disassemble and get the knuckle on a press in the end, drill out the threads, and just ran a longer bolt with a locking nut on the end. best of a bad situation...haha. just as well, too, 'cause the bearings were bad.
It's reseeded in the hole and since the timing tensioner pulley doesn't have a removable bolt the hole and the threads need to be the same size. I'll take a picture tomorrow to show you. But iv got some extra heads so I'll most likely swap them over since I screwed theses ones up....
Hmmm. There's rust on the broken surface of the bolt.
Believe it or not, that could be a good sign. Unless that engine has been sitting out in the rain for a few days, that rust could have propagated through an existing crack in the bolt. Which could mean that bolt isn't in there all that tight. I still like the idea of using a left-hand drill bit (which will just spin it right out), but if you're impatient that bolt is big enough that you might be able to tap it out with a sharp punch. A few gentle taps, and if the bolt starts turning, you'll have it out in no time.
05-23-2017, 04:15 PM
