I noticed the pushrod cover was leaking a little bit from the back lower corner, closest to the firewall. I thought maybe the bolt needed to be tightened so I grabed a wrench and with almost no effort at all the bolt head snapped right off. Of course this is the most difficult bolt to get to. I went out and bought a right angle drill attacment, and a box of drill bits. Well I broke every small bit that I had and managed to drill out 1/16 deep. It got dark and cold so this is where I left everything yesterday. I know if I just use gasket silicone it will slow it down, but its still going to leak. Does anyone have a suggestion for getting this drilled and tapped. Is there a special bit I can get that will do this and not break? Obviously space is one of the hardest parts of this. Anyone have a 2f laying around that they want to get rid of? Mine has 346k on the clock so wouldnt mind having a newer motor that doesnt have this problem.
Broke a bolt in the block, need help
- Thread starter csd4682
- Start date
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Irwin Hanson makes nice reverse cut drill bits for removing bolts and studs as well as screw outs. I have one of their kits, it's very handy.
That's a short bolt in that cover.
Amazon.com: Irwin Industrial Tools 11135 Screw Extractor and Drill Bit Set, 35-Piece: Home Improvement@@AMEPARAM@@http://ecx.images-amazon.com/images/I/51W3SWJZ19L.@@AMEPARAM@@51W3SWJZ19L
That's a short bolt in that cover.
Amazon.com: Irwin Industrial Tools 11135 Screw Extractor and Drill Bit Set, 35-Piece: Home Improvement@@AMEPARAM@@http://ecx.images-amazon.com/images/I/51W3SWJZ19L.@@AMEPARAM@@51W3SWJZ19L
left hand drill bits 
what size is that cap screw 6 mm or 8 mm?
what size is that cap screw 6 mm or 8 mm?
I will go at it in a worse case scenario
You could have two cause of the problems
1. It is probably the wrong bolt thread for the hole.
2. The bolt may be correct thread pitch and size but may be too long and bottomed out in the hole
No Left hand drill bit alone is going to overcome the above.
Use a small center punch and mark the center of the bolt.
Drill very slowly or you will break the drill bits.
Use a small drill bit and drill a pilot hole throught the broken bolt. Small = less than 1/8".
Now you can step up and use the left hand drill bits, if you want. If you drill very slow, they may catch and grab the bolt and unscrew it. If the bolt is one of the scenerios mentioned above, you will be wasting your time and money with left hand drill bits.
Increase the size of drill bit and continue drilling it out.
Lets say your drill goes a little off center of the bolt. When you notice that you can sometimes work the broken bolt out since it does not have all of the thread radius holding it.
If you get all crazy with your drill, you can always put a heilcoil in the hole.
Doing this slowly will be a heck of lot less work than replacing the 2F.
Good luck.
You could have two cause of the problems
1. It is probably the wrong bolt thread for the hole.
2. The bolt may be correct thread pitch and size but may be too long and bottomed out in the hole
No Left hand drill bit alone is going to overcome the above.
Use a small center punch and mark the center of the bolt.
Drill very slowly or you will break the drill bits.
Use a small drill bit and drill a pilot hole throught the broken bolt. Small = less than 1/8".
Now you can step up and use the left hand drill bits, if you want. If you drill very slow, they may catch and grab the bolt and unscrew it. If the bolt is one of the scenerios mentioned above, you will be wasting your time and money with left hand drill bits.
Increase the size of drill bit and continue drilling it out.
Lets say your drill goes a little off center of the bolt. When you notice that you can sometimes work the broken bolt out since it does not have all of the thread radius holding it.
If you get all crazy with your drill, you can always put a heilcoil in the hole.
Doing this slowly will be a heck of lot less work than replacing the 2F.
Good luck.
I agree with all of the above. I'm too well versed in removing broken bolts. I would only add, use drill oil to lubricate your drill bit. Also, make sure that you have a drill bits designed to be used in metal when you do this. Not multi-purpose drill bits.
One alternate solution that I have used in the past is to use an awl. First let the bolt soak with some serious rust buster. PB is good, but there is the 40 buck a can stuff too. After letting it soak for a day or two, put the tip of the awl in a spur on the broken bolt. Get the awl at an angle so that when you tap the end of the awl with a hammer so you will essentially spin the bolt out. Rotate the awl with the bolt so you can keep spinning it out. Of course this technique wont work if space doesn't allow you to get at the right angle to put the awl on a spur or the bolt has been sunk into untapped metal at the bottom of the thread.
I would try this technique before you use a drill and use so-called easy outs because if those things break off in your bolt, they are hardened metal and therefore impossible to drill through again. I've probably broken a nearly equal number of so-called easy outs in sheared off bolts to the number of bolts that I have sheared off. Most of the time the so-called easy outs can be backed out of the bolt, but sometimes not. Take your time and never, ever torque hard on a so-called easy out. They are super hard steel and therefore much more brittle and prone to breakage if tweaked or twisted incorrectly. This is to easy to do, especially in a cramped-space situation. Dont ask me how I know this......
Good luck and take your time. It'll come out out.
- Thread starter
- #7
Well I am reading posts 5 and 6 too late. I have spent another 30.00 on bits, broken most of them, and the final one broke inside the hole I was drilling out. I think at this point I am
F%@#ed So I have tried for several hours now to get the broken bit out but its not happenening. I will use gasket silicone to slow the leak down untill I decide what to do.
F%@#ed So I have tried for several hours now to get the broken bit out but its not happenening. I will use gasket silicone to slow the leak down untill I decide what to do.
Same thing happened to me three years ago. It was one of the lower bolts near the fuel pump. Broke the easy out in the drilled hole then used regular and reverse thread bits with a right angle drill adaptor till I got it all out. I put many hours and at least $100 in bits to get it out. Then i retapped to the next biggest size up.
My plan if I could not get it done was to create a tensioned bracket off one or two other bolts to press the side cover against the block so it sealed.
Good luck!
My plan if I could not get it done was to create a tensioned bracket off one or two other bolts to press the side cover against the block so it sealed.
Good luck!
John McVicker
SILVER Star
My idea may not get you enough room to try... but if you completely took off the side cover, would that expose enough of that bolt to get some vice grips on it ??
Good luck, John
Good luck, John
It may be too late for my suggestion, and it works better and is a lot safer with the engine out but what I usually do is if there is part of the broken bolt close to the mating surface, I'd go and grab a suitable nut and hit it with welder and weld the center of the nut to the broken bolt stud. You may also want to try a little penetrating spray in the gap before you weld the nut on. Once the nut is on I usually let it cool and then get the blow torch out and heat the thread area in the block while freezing the bolt head area. It may take a couple of goes sometime but even the most stubborn ones have come out. I had a couple of very stubborn ones too, I'm in the middle of a rebuild. Heat and freeze got them of thankfully without breakage but they were corroded. I'm no expert but just my 2 bobs worth.
I've broken that bolt before, and broke an easy out in the bolt hole. Miserable to get out because of the lack of space. Ended up getting a 90 degree attachment for the dremel and some diamond bits. Took it slow and burned through 3 bits but eventually got the bolt out and retapped the hole. Back corner bolt on mine (82 FJ40) is longer than the others, as its supposed to have a spacer on the front and wire clamp - if you forget the spacer when reinstalling its easy to bottom out the bolt and twist the head off.
this is what i would try, often works for me
is there any part of the bolt that is clear of the thread boss?
I too have broken drill bits and I also broke a snap-on ease out bit in teh same manner... I was lucky and able to drill out a bolt on an intake (vey small drill bit size) and I went up a size or two and then used the small ease out and put too much force on it and it broke even with the thread boss...this was on the thermostat housing bolts on a GM intake. I was never able to get that bolt out or the ease out which is harneded. It was a crappy stock GM intake on my old truck and I just ended up buying aftermarket one. ONly way I could guess to get the thing out was to jig the intake up on a drill press or mill and use some kind of diamond bit...I tried dirlling out the ease out but evey time the cobalt bits would hit the ease out the drill would walk off the target. I was slightly pissed.
Th only good part of the story is that I won a bet with one of the old school mechanics at the local GM shop who told me he could get it out.....I gave him the intake....never heard anything more on that one.. Run studs if you swap things around on a aluminium intake.
My lessson learned was to drill out the bolt as far as you can (using progressively larger drill bits), take your time and drill it out as far as you can up to the point where you think yoiu may hit the threads...then stop and use appropriate ease out or left handed drill going slow and applying moderate force in a smooth manner to see if the drilled otu bolt will move.
If you have any thread showing above the thread boss...you might could (1) saw a notch in the top of the bolt and use a screw driver to move the bolt, (2) see if you could use vise grips to attach to the bolt and turn it (3) have someone weld a nut to the bolt and see if you can turn it loose that way.
If the bolt broke below the top of the thread boss (hole) you are pretty much screwed I think at this point since the drill bit broke.....
I do know that heat works wonders sometimes but you need something to grab before applying the torch. You might take the truck by a machine shop and get one of the guys to look at it to see what might make sense to do.
I too have broken drill bits and I also broke a snap-on ease out bit in teh same manner... I was lucky and able to drill out a bolt on an intake (vey small drill bit size) and I went up a size or two and then used the small ease out and put too much force on it and it broke even with the thread boss...this was on the thermostat housing bolts on a GM intake. I was never able to get that bolt out or the ease out which is harneded. It was a crappy stock GM intake on my old truck and I just ended up buying aftermarket one. ONly way I could guess to get the thing out was to jig the intake up on a drill press or mill and use some kind of diamond bit...I tried dirlling out the ease out but evey time the cobalt bits would hit the ease out the drill would walk off the target. I was slightly pissed.
Th only good part of the story is that I won a bet with one of the old school mechanics at the local GM shop who told me he could get it out.....I gave him the intake....never heard anything more on that one.. Run studs if you swap things around on a aluminium intake.
My lessson learned was to drill out the bolt as far as you can (using progressively larger drill bits), take your time and drill it out as far as you can up to the point where you think yoiu may hit the threads...then stop and use appropriate ease out or left handed drill going slow and applying moderate force in a smooth manner to see if the drilled otu bolt will move.
If you have any thread showing above the thread boss...you might could (1) saw a notch in the top of the bolt and use a screw driver to move the bolt, (2) see if you could use vise grips to attach to the bolt and turn it (3) have someone weld a nut to the bolt and see if you can turn it loose that way.
If the bolt broke below the top of the thread boss (hole) you are pretty much screwed I think at this point since the drill bit broke.....
I do know that heat works wonders sometimes but you need something to grab before applying the torch. You might take the truck by a machine shop and get one of the guys to look at it to see what might make sense to do.
- Thread starter
- #14
Thank you everyone for the suggestions. I have decided to pull the motor. I am getting too good of a deal on another motor with a 3rd of the mileage, so I think I will try a tension bracket to hold me over untill the new motor is installed. Once the motor is out, I will probably take it to a machine shop and have the bit pulled and a new hole tapped.
Resurrecting an old thread here because I have the same problem. I broke the top bolt, second one in from the front of the motor. I broke an extractor trying to get it out. I've drilled out most of the extractor but I think I'm off center and still haven't gotten the bolt out. I'm not sure at this point how to repair it. Any advice on how to make a decent repair?
Since that bolt hole with the busted bolt is at the top and any oil splashing inside the pushrod cover is minimal, maybe try just installing the cover without using that bolt? Use a glob of Toyota black FIPG in that spot and likely you’ll be good.
Won’t hurt to try.
Won’t hurt to try.
Nut, weld the broken face to the inside of the bolt, let cool, back it out
At this point there's nothing to weld to
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Looks like you have got yourself in a corner - opened up the entrance to the hole and damaged the surrounding sealing surface. Stud extractors are great when you have a bolt that sheared into a thread purely from over-torqueing. But if the bolt snapped because it's seized in with rust, you stand to make a bigger problem for yourself when using a stud extractor... and it snaps in. So now you need to drill out an irregular, hardened steel object instead of the soft bolt...
I think it's about damage limitation. I would try to punch the centre of the bolt/stud mess and go in gently, slowly with quality drill bits, starting at around 3 or 4 mm. I'd say there's not much chance of you getting the stud out now, so most likely you will have to drill it out and put in a thread insert such as a Helicoil. Then perhaps epoxy fill the gouge marks on the seal surface.
I think it's about damage limitation. I would try to punch the centre of the bolt/stud mess and go in gently, slowly with quality drill bits, starting at around 3 or 4 mm. I'd say there's not much chance of you getting the stud out now, so most likely you will have to drill it out and put in a thread insert such as a Helicoil. Then perhaps epoxy fill the gouge marks on the seal surface.
