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Need advice - broken oil pump bolt...


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I really need some advice. I've read a bunch of posts on broken bolt removal, but so far I have had no luck. I replaced the seals & gaskets on my oil pump this weekend, replaced it, snugged down the bolts, torqued to spec...then the last bolt sheared off. It is the lower, right hand bolt (one of the three short ones that surround the impeller portion of the pump). I immediately removed all the bolts and the pump hoping to find something to grab with vice grips, but no such luck - it sheared almost flush with the block. I got out my left-handed drill bits hoping to back it out, but the bits just drilled into the bolt remnant without grabbing. I started with a relatively small bit and worked my way up to 3/16, so now I've just about drilled out the bolt completely. I did try an EZ-out a couple of times along the way, but I was afraid of breaking it off. Now I have a 3/16 hole, virtually no bolt left, and a halo of bolt steel protruding around the hole. What next? Should I drill a little bigger to clear out the last of the old bolt, then tap for a larger bolt? Helicoil? Timesert? Whatever I do, I'm wondering if I need to pull the engine at this point since I can't really turn a tap squarely working from a above or below. I admit, I'm a bit intimidated and discouraged at this point, so any ideas are welcome. Thanks, and sorry for the long post.

- Ian

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yeah these suck. DO NOT touch that EZ out again..your best bet is to throw that thing away right now. i would not pull the engine, no way it's worth all of that effort and hassle. have you drilled all the way through the bolt? i believe that is one of the short oil pump bolts, which is good because it's the same length as the others, you should be able to tell how deep it is and how deep you've drilled by comparing it to the others. i would make sure you're all the way through it. sounds like you were able to get it centered fairly well. if so, drill it out again until it starts breaking up and start extracting pieces. combination of heat and cold may help it come out but i don't know how much heat i'd put on an area that seals your oil pump gasket either. keep using left handed drill bits on it. i think i would keep progressing with larger drill bits and just drill it out. hope the threads are good, but if not you can helicoil it, that's not hard at all. don't let that scare you if you've never done it bvefore.

 

you may get away without needing a helicoil. if you get it out, chase the threads with a tap. the tapped hole will be deeper than the original stock bolt, so even if you messed up some of the threads there will be good threads deeper in. so get a bolt that's longer than the stock bolt that will reach those good threads.

 

if you have to just drill it out and use a helicoil that's a great option. a little more work and requires a helicoil part/kit but well worth it and works great. you'll be able to get it plenty straight to work. if for some reason when yo'ure done you feel like the helicoil isn't as straight as you would have liked, then use a compression washer under the head of the bolt for extra insurance. it'll be fine, these aren't high load and high force bolts and there are 4 others.

 

i had a water pump bolt shear off that could not be drilled and was obviously not the stock bolt, it was somethign very hard and i couldn't weld to it. i bought 2 or 3 very expensive drill bits that were supposed to be able to drill anything and they wouldn't touch it. so i drilled a hole right next to and intersecting with the existing hole. once it was deep enough i used a punch to knock the bolt into the hole i had just drilled. fortunately i had a spare block that i drilled all around to make sure there weren't any passages or anything that i would hit by drilling this hole. makes sense that nothing was there, but i wanted to be sure. i don't recommend this, but it was the only thing that i could do and it worked. i actually had to do this to my current daily driver and it's held up just fine.

 

i've used very, very, very thin needle nose pliers before and they help as well. i got them from a machinist friend, i don't know if they are available or he made them. with the bolt drilled out, you can insert these pliers and open them while in the hole, this will grip the bolt and you may be able to turn it out this way. if not, these pliers still help with extracting the bolts pieces once you start drilling it larger and larger, but they aren't necessary.

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yeah these suck. DO NOT touch that EZ out again..your best bet is to throw that thing away right now. i would not pull the engine, no way it's worth all of that effort and hassle. have you drilled all the way through the bolt? i believe that is one of the short oil pump bolts, which is good because it's the same length as the others, you should be able to tell how deep it is and how deep you've drilled by comparing it to the others. i would make sure you're all the way through it. sounds like you were able to get it centered fairly well. if so, drill it out again until it starts breaking up and start extracting pieces. combination of heat and cold may help it come out but i don't know how much heat i'd put on an area that seals your oil pump gasket either. keep using left handed drill bits on it. i think i would keep progressing with larger drill bits and just drill it out. hope the threads are good, but if not you can helicoil it, that's not hard at all. don't let that scare you if you've never done it bvefore.

 

you may get away without needing a helicoil. if you get it out, chase the threads with a tap. the tapped hole will be deeper than the original stock bolt, so even if you messed up some of the threads there will be good threads deeper in. so get a bolt that's longer than the stock bolt that will reach those good threads.

 

if you have to just drill it out and use a helicoil that's a great option. a little more work and requires a helicoil part/kit but well worth it and works great. you'll be able to get it plenty straight to work. if for some reason when yo'ure done you feel like the helicoil isn't as straight as you would have liked, then use a compression washer under the head of the bolt for extra insurance. it'll be fine, these aren't high load and high force bolts and there are 4 others.

 

i had a water pump bolt shear off that could not be drilled and was obviously not the stock bolt, it was somethign very hard and i couldn't weld to it. i bought 2 or 3 very expensive drill bits that were supposed to be able to drill anything and they wouldn't touch it. so i drilled a hole right next to and intersecting with the existing hole. once it was deep enough i used a punch to knock the bolt into the hole i had just drilled. fortunately i had a spare block that i drilled all around to make sure there weren't any passages or anything that i would hit by drilling this hole. makes sense that nothing was there, but i wanted to be sure. i don't recommend this, but it was the only thing that i could do and it worked. i actually had to do this to my current daily driver and it's held up just fine.

 

i've used very, very, very thin needle nose pliers before and they help as well. i got them from a machinist friend, i don't know if they are available or he made them. with the bolt drilled out, you can insert these pliers and open them while in the hole, this will grip the bolt and you may be able to turn it out this way. if not, these pliers still help with extracting the bolts pieces once you start drilling it larger and larger, but they aren't necessary.

 

Gary,

Thanks for all the great information. I had read about your struggles with the water pump bolt, and it sounds far worse than what I'm facing - gives me a bit of confidence that I can actually fix this mess! I appreciate the help.

- Ian

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no problem ian. i'll give you my cell phone number if you'd like over PM or email. just send me a note if you run into anything or have questions. unfortunately i've dealt with many sheared bolts, i'd be stoked if those circumstances and lessons helped someone else!

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Only thing I want to add to GrossGarys post is "don"t drill too deep" The oil pump pickup passge is behind those bolts, at least the bottom right corner one and the top one diagonal form it, if one of those you're working on then don't go deeper that stock or use a longer bolt. you've got maybe a few mm but not more.

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no problem ian. i'll give you my cell phone number if you'd like over PM or email. just send me a note if you run into anything or have questions. unfortunately i've dealt with many sheared bolts, i'd be stoked if those circumstances and lessons helped someone else!

 

Gary - I really appreciate the offer. If I hit a seemingly insurmountable snag, I'll PM you with a cry for help! I will also post the outcome when I get this little problem resolved. Thanks again for the guidance.

- Ian

 

PS - thanks to Gloyale, too, for the warning about the bolt hole depth - I wondered if suddenly I'd break through into an oil passage - it was definitely a factor in my stress level!

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I can look a the block I have disassembled at home tonight anbd tell you excactly how far and how deep you can go. Which number hole is it? 1 represents the long odd ball, and 4 is the lower left corner and is longer. 2,3,and 5 represent the short bolts round the pump rotor.

 

1 2 3

Pump

4 5

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Success is mine!:banana: I went up two drill bit sizes successively and the remaining piece of bolt just came loose in the hole - I backed it out with my fingers. The threads seem to be intact as I was able to turn a bolt in and tighten it up. Thanks for all the help!

- Ian

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I looked at a block today. I was wrong, none of the bolt holes are over oil passages. If you were to drill through it would just punch through into the open crankcase above the oilpan. But there is only 3.5 mm in depth beyond the existing hole to drill before you punch through. Perhaps as much as 5 mm for the upper right corner bolt but all the others are pretty much as deep as they can go.

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  • 2 years later...

I broke an oil pump bolt yesterday (91 Loyale, replaced the pump, think it's original at 175k). The sheared-off portion does not stick out, so there's nothing to grip.

 

I only have the rest of the day today before I have to have it running again, so I'm thinking these are my options:

 

1) Leave the new pump in place with the broken bolt (I did use RTV in addition to the mickey mouse gasket) and keep an eye on it for leaks. Pro: easy way out; Con: it might leak as much now as before I replaced the pump and I'll have to replace the timing belts again when the oil splashes up there (the TB covers are shot--planning to leave them off).

 

2) Drill it out with a reverse bit until either a) I can remove the bolt or B) if it won't come out, drill it a little bigger and use a helicoil. I read a bunch of threads on broken bolts, but as this is my first time with one, I'm wondering if I should start with a small bit and hope I get it centered, or start with a bit that matches the bolt size and use the hole in the oil pump rump roast'y as a drilling collar... Pro: it would be done right; Con: might take more time than I have, but maybe I don't have a choice.

 

What do you think? Is #1 viable, or just stupid and lazy?

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First remove it and get every trace of RTV out of there.

 

That stuff will squeeze out into little beads in there and then travel down the line to clog stuff up.

 

Even if you end up HAVING to run with only 4 of 5 bolts, at least you won't clog a main bearing

 

Plus with the pump removed, there MAY be enough sticking out to grab with Vice-grips.

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First remove it and get every trace of RTV out of there.

 

That stuff will squeeze out into little beads in there and then travel down the line to clog stuff up.

 

Even if you end up HAVING to run with only 4 of 5 bolts, at least you won't clog a main bearing

 

Hmm. Thanks. I did see this in another thread, so I only used a *little* RTV (ultra black) around the very perimeter of the pump (as far from the gasket as I could keep it) as insurance. I ended up just leaving it on less one bolt. I'll keep a close eye on it, and it it dribbles any I guess I'll scrape out the RTV and extract that bolt. (I guess this is evidence I'm something of a hack :)) I admit, I'm a little intimidated with all the extraction horror stories I've read.

 

Plus with the pump removed, there MAY be enough sticking out to grab with Vice-grips.

 

I do appreciate the tip, although enough of the shaft came along with the head that I'm sure it's below the surface. Bummer...

 

Thanks, guys, for your responses--this forum is fantastic! I probably never would've tried this without all of the information available here.

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