Helicoil or drill?

[Zoltan]

I replaced the starter yesterday and the upper bolt got stripped. Should I helicoil it or drill through the whole and put a smaller bolt and nut in? I've never done either.

[kassim503]

i probably wouldnt do the bolt and nut combo because the flywheel is spinning at the speed of light 1/2 of an inch in there. Im sure helicoils would work, its not a high stress application and you dont gotta hold any fluids from leaking nowhere.


You can also re-tap the remaning bolt to an american size, or the next size up with metric- thats what I did when I stripped something on the car, dont remember what I stripped tho. But it works, you just have to make sure the major diameter of the existing thread dosent conflict with the minor thread with the new thread.

I would recommend helicoiling it, its eaiser and the results are better

[asavage]

While a helicoil is unquestionably the stronger and more professional repair, you might not have a good shot at this one with the engine installed in the truck. Maybe if you remove the intake/exhaust manifolds . . .



. . . and perhaps even remove the draft tube assy, to gain good access to the hole.

If you've never installed a helicoil before, I would probably advise to through-bolt the starter. Use a grade five bolt if you go SAE, or 9.8 (or, better, 10.8) if you go metric.

Tapping to an oversize is tricky. If you can tap oversize correctly, you can helicoil. I love helicoils but installing one in a hard area like that isn't the ideal introduction, and if you have the room to through-bolt, that's foolproof.

[Nissan_Ranger]

While a helicoil is unquestionably the stronger and more professional repair, you might not have a good shot at this one with the engine installed in the truck.

If you've never installed a helicoil before, I would probably advise to through-bolt the starter. Use a grade five bolt if you go SAE, or 9.8 (or, better, 10.8) if you go metric.

Tapping to an oversize is tricky. If you can tap oversize correctly, you can helicoil. I love helicoils but installing one in a hard area like that isn't the ideal introduction, and if you have the room to through-bolt, that's foolproof.

X2 on the idea of through bolting. I'd take the further step of using a nylock or self locking nut on the end of the bolt to further improve the security of the join...

N_R

[kassim503]

I might steal this thread for a bit, but its right up this threads description's alley.

Today I finally broke down and went to exchange the electric fans to a solid mechanical fan- for increased cooling and also to replace the electric fans that plagued me with problems. In the process I broke off a water pump bolt, the bolt is a long 6MM x 1.0 bolt, with the 10MM head. Now, the car dont leak without it, but im sure this is not gonna hold true for a while because if im correct, it helps hold the timing chain cover close to the block and water pump for a good seal.

Ill probably get a pic of it sometime soon.

What would be the best method to extract the thread from the block and re-install a new bolt in its place?

Also, by the way, I dont think the fastener failure was because of overtightening, it seemed to have been weakened by corrosion and years of abuse, cause when it broke I literally had my finger on the end of the ratchet to tighten it.

[asavage]

Kassim, you are not going to like the answer.

[kassim503]

I knew itd be bad

You think I would be able to vice grip the nub sticking out if i take the chain cover off?, im replacing the timing chain soon.

[asavage]

I have done quite a bit of this kind of work, and I don't think that there is a way you can extract the broken bolt without removing the timing cover.

If you have a nub, I'm certainly you can use something like a vise grip on it, and it will very likely spin right out (assuming you lubed the threads upon installation, which is my std practice: every threaded assy. gets either lube or Loctite).

If the nub is not there or not enough to grab, based on the fact that it was just put in, I'd face it off flush to the gasket surface, very carefully and with patience, center punch the bolt, drill it and use a std extraction tool ("EZ-out" type of thing). Unless it is cross-threaded or has been in long enough to rust to the block, it will spin right out.

If you were very careful when you center punched it, and an extraction tool doesn't work, you can then move on to drill it out completely to the minor diameter of the hole, then pick the bolt's remains from the tapped hole, then run a 6mmx1.0 tap through for cleanup.

If the the threads become damaged, or if the hole is in a non-ferrous metal (ie aluminum), I go from "failed extraction" directly to a helicoil, I don't try to clean up the hole. This only works if you were very careful to CENTER the punch and drill the hole straight. Off by .040" and you're screwed, and the amount of work is tripled. You can punch and drill it by eye, just be patient and triple check. Once it's drilled, it is much harder to center the hole!

[Nissan_Ranger]

I knew itd be bad

You think I would be able to vice grip the nub sticking out if i take the chain cover off?, im replacing the timing chain soon.

The very best way to get hold of that broken fastener is to beg, borrow, or steal a MIG welder with .024 wire and C25 gas. Hold an appropriate sized nut with a pair of needle nose vise grips and put it over the nub. Start the welding on the nub; get it WELL heated/puddled, and then weld it to the inside of the nut you're holding. Let it cool on its own; do NOT flood it with water or it will become brittle and break again. After it is cool, rap it a dozen or so times lightly with a small ball peen hammer and flood it with penetrating oil. Delicately work it back and forth (Loosen/tighten/loosen/tighten...) and gradually increase the range of movement until you are confident it will come out. Let me know how it works...

Regards,

N_R

[asavage]

There would be much less chance of failure by facing, drilling, and even helicoiling, than an inexperienced welder trying to weld with .024" wire inside the minor diameter of a 6mm nut.

Unrelated: ever removed a bearing's outer race from a housing by laying a bead on the race's face? Works like a charm.

[Carimbo]

If you have a nub, I'm certainly you can use something like a vise grip on it, and it will very likely spin right out (assuming you lubed the threads upon installation, which is my std practice: every threaded assy. gets either lube or Loctite).

For this application I like to coat the entire surface of the bolt w/ antiseize paste. Some of those waterpump mounting bolts often show up corroded to the point where there is not much material left in the middle (unthreaded) part; just waiting to snap in half. Which of course would not be so much of a problem (leaves enough to grab) but who wants to gamble for extra headaches?

DO NOT reinstall any corroded bolts-- get new ones and coat them.

very carefully and with patience, center punch the bolt, drill it and use a std extraction tool ("EZ-out" type of thing). Unless it is cross-threaded or has been in long enough to rust to the block, it will spin right out.

An alternative that has worked surprisingly well for me is to use a reverse-direction drill bit. Once it starts to cut into the bolt it often unscrews it! Reverse-direction drill bit not so easy to find but they are around-- specialty fastener supply shops usually stock them.

[asavage]

Reverse-direction drill bit not so easy to find but they are around-- specialty fastener supply shops usually stock them.

Tell me about it . . .

I just bought two five-bit sets, at $40 each!
Boss ordered them, didn't check the price. Nobody in Jefferson County can sell them to me. In my line of work, the smallest size is the one that breaks first. Got a source for them, Carimbo? I suppose I should call Tacoma Screw tomorrow.

Anyway . . . yeah, they work, esp for a lubed part, but you won't buy them just anywhere. Even my tool truck guys struck out.

And, even for left-handed bits, you need to have the hole center punched on the money.

==========================

Somewhat related: last summer, I dragged boss' son's car back from Ellensburg, across the Cascades . . .

because he was moving to this side. I told 'em to just leave the car there, but they decided to bring it over, and I was getting paid, so [shrug].

The reason it wasn't driving was the 2TC's fuel pump died, and in the process of replacing it, someone broke off an 8mm mounting bolt. Then drilled it major off-center (it's on the side of the block). Then broke off a drill bit in the block. Oy!

While I've repaired worse, the car did not demand that kind of investment: I faced off all the damage, drilled and tapped a 10-32 hole off to one side of the damaged area, and made a block-off plate for it. Hung an electric fuel pump on the frame rail, and done!

Got the thing running well, vacuumed, waxed, cleaned up and greased etc., and they decide that now they don't want it. Sold it for $500, it's running around town now.

Could have saved a lot of money by scrapping it back in June. Well, I got paid -- by the hour!

[Zoltan]

While a helicoil is unquestionably the stronger and more professional repair, you might not have a good shot at this one with the engine installed in the truck. Maybe if you remove the intake/exhaust manifolds . . .

Haven't gotten to it yet, but in case I have to take off the manifolds, do I need new gaskets or the old one(s) are reusable? I am looking at a major operation behind the dash too... When I turn the ignition to start, sometimes I see smoke coming out from the vents and there's a burnt smell ... Oh, and the starter turns very sloooowly while the smoke rises. So I am pretty sure there is a short there somewhere. I just took the car to Sears for a battery/charging system load test, and everything was fine... but it still left me stranded in the parking lot. I felt like hitting my head repeatedly into the hood.

[Nissan_Ranger]

There would be much less chance of failure by facing, drilling, and even helicoiling, than an inexperienced welder trying to weld with .024" wire inside the minor diameter of a 6mm nut.

I shall have to add that any tech advice I give is based on the premise that the recipient knows enough to try the job himself or let another do it for him; in this case the owner of the welder. The welding method is definitely easier than trying to drill a straight hole in a bolt with such a small diameter... I honestly didn't think of whether kassim503 was experienced as a welder or not, but he DID strike me as being an inexperienced mechanic by virtue of having broken the bolt; he'd prolly have as much trouble doing the drilling method of extraction. Regardless, I do hope he gets it out one way or the other.

Unrelated: ever removed a bearing's outer race from a housing by laying a bead on the race's face? Works like a charm.

Yes indeed... The inner races for the bull gears in a D-6 caterpillar rear end come to mind as a perfect place for that method of removal.

regards,

N_R

[Carimbo]

Reverse-direction drill bit... Got a source for them, Carimbo? I suppose I should call Tacoma Screw tomorrow.

Yes, Tacoma Screw had them easily, price quite reasonable IIRC.