repairing stripped threads with JB Weld

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I have stripped out the threads in a 1/4" bolt hole in an aluminum transmission case. I can't get a drill in there to be able to use a heli-coil type of insert, and I have decided to use JB Weld to repair this as the bolt that goes into this stripped hole just locates a bracket which is held on securely by another, larger bolt. I haven't used JB Weld before, but I am confident this is an appropriate situation to try it...

I checked out the website where it tells me to clean with acetone, no problem. My question is how to proceed from there, assuming that I want to be able to remove and replace the bolt after it cures.

Do I just force the epoxy mix into the hole and then jam the bolt in ? Or should I coat the bolt with oil so the JB Weld doesn't bond to it? I am worried that if I don't do something, when I unbolt the bolt, it might pull the whole wad of epoxy out instead of unscrewing.

Thanx for not telling me not to strip out bolt holes in aluminum, I already know that this is a bad thing!

__ "All it took was all I had..."

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Emmo writes:

(1) JB "Weld" is a phony name for what is just epoxy.

(2) Epoxy does not bond to oxidized aluminum.

(3) Have you considered a thread repair insert?

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rethread the hole to a larger size, turn down the bolt dia, if needed...

xman

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you really don't want to use jb weld for thread repairs ,jb weld is great for repair work for patching holes and for holding some light weight brackets on, but for making threads it wouldn't be the best since the threads will actually fail it isn't designed for holding that kind of pressure that threads apply or the bolt will never come out again which isn't good either ,now to actually do the job right and look professional you can either drop the tranny down enough to get a drill in to install the helicoil or remove it completely and the last go buy a right angle adaptor for your drill or a right angle air powered drill this is angled at 90 degrees to fit in tight places and is a great investment ,but another idea you could do is since you stripped out the hole is take the next size tap and tap out the hole the go get a piece of aluminum rod and drill out the center and tap it then cut it to length to fit flush in the tranny and helicoil it and get a lil longer bolt with the correct thread size and put a nut on the bolt and put it in the rod and part way and tighten the nut against to lock it in place now proceed to use a die and make threads to match the over size threads of your tranny on the outside of the rod once the threads are done coat the outside of the rod liberally with loctite and then using the bolt thread it in the hole til snug and then let it sit for a few minutes loosen the nut and remove the bolt and you just done a repair that will probably out last the tranny itself ,if you get a higher grade of aluminum then the cast aluminum case you may not even have to use a helicoil at all in the threads ,just don't use stainless hardware in the aluminum threads it will corrode it use the stock hardware good luck

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I once badly crashed a model airplane with an OS 40 straight into an asphalt parking lot. That motor cost me about 35 bux so I was determined to fix it. Case was badly cracked and the carb boss was sheared off. I carefully cleaned everything and v grooved the cracks. Cleaned again and preheated the case in the oven. Mixed up a fresh batch of JB weld and carefully worked it into the v grooves. Engine ran fine and I still have it. JB weld is pretty good stuff if you use it right.

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before,

to

pull

I don't think you'll have any luck with that idea. The tensile strength of the epoxy is far less than needed, even if you used a good release agent and could get the bolt out afterwards. You wouldn't be able to tighten the connection well enough to do any good without pulling the threads again. You're sort of stuck. There's lots of things you can do to repair the thread, but you'll have to have access to the hole with at least hand tools to accomplish them.

Harold

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If you really care, get a drill in there (you might need to saw the car in half to get to it).

Otherwise glue a _stud_ in there with JB Weld and put a nut on the top. But this is a bodge.

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But I would do that with LockTite.

Nick

--
Motor Modelle // Engine Models
http://www.motor-manufaktur.de
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Nick Mller wrote:

I'd go for an interference fit... hone the hole carefully and maybe use a reamer to get it square... lathe a stud just *over* the hole size, then heat the case, insert the stud, cool. Done.

but, a 1/4" bolt on a tranny? for what? The pan??

_-_-bear

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This is a Mopar 46RH auto transmission. The gearshift cable bracket is held in place with a 5/8" bolt through a cast-in ear, then has a long extension to keep the bracket located and straight. This is where the 1/4" bolt goes. A stud would work fine for this, as there is no real force on this end of the bracket, so thanx to those who suggested it...

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Emmo wrote:

They beat me to it, but I was going to suggest taking a 1/4" stud, bashing one end a little flat so it "swells" a bit at right angles to the bashing so it's an interference fit in the aluminum, and then tapping it into that violated hole with some JB Weld around it.

Follow by using an elastic stop nut which you won't have to tighten more than snug to keep it in place, thus avoiding jacking the stud out. Or, just put some JB Weld under the nut and do it finger tight, you can always repeat the process if you ever need to get it off again.

Happy Holidays,

Jeff

--
Jeffry Wisnia

(W1BSV + Brass Rat '57 EE)
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On Sat, 24 Dec 2005 11:47:54 +0100, snipped-for-privacy@gmx.de (Nick Mller) wrote:

Not in a stripped hole - you'd need some gap filling too.

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Well, as my son describes it, I 'Hardy-boyed' it by making a stud, gluing it in with the JB Weld, and putting a nut on it. It is solid enough to hold the end of the bracket in place, all the force is shear, so I expect it to be just fine.

Thanx for all the help!

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Make yourself a self tapping stud- use a 5/16 self tapping metal bolt- cut off the head and turn the end to 1/4" and thread it- double nut it and thread the 5/16 portion into your block

before,

to

pull

already

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Won't work, you're screwed!

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Used to work fine in the 60's on VW head studs- they made a special stud with a self tapping end so you could replace a pulled stud right alongside the road.

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I appreciate all of your responses, even though most of them were discouraging... Terry mentioned that LockTite makes a thread restorer kit that includes the release agent, so I think I will try to find that.

Otherwise, there is no way I am pulling the tranny, and I would probably have to take Andy's suggestion of sawing the car in half to get the drill in there, so worst case, I will either use a larger sized self-tapping fastener, epoxy it in permanently, or wrap duct tape around it...

Thanx!

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"Emmo" wrote: (clip) Terry mentioned that LockTite makes a thread restorer kit that includes the release agent, so I think I will try to find that. ^^^^^^^^^^^^^^^^^ Right! Loctite and Permatex both make thread repair kits, which include the release agent. They will work fine in this application. Don't try to use this on a head bolt or a bearing cap, but for non critical applications, they're fine. Go to a bearing supply house.

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I think Loctite and Permatex are the same now - in any case, I found the thread repair kit at my local Oreilly's Auto Parts store, which I like to patronize as they support drag racing...

Thanx!

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On Sat, 24 Dec 2005 16:33:58 GMT, "Leo Lichtman"

Permatex and LocTite are the same company.

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