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..."



Re: repairing stripped threads with JB Weld
Emmo writes:

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(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?

Re: repairing stripped threads with JB Weld

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

xman



Re: repairing stripped threads with JB Weld
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


Re: repairing stripped threads with JB Weld
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.


Re: repairing stripped threads with JB Weld

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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





Re: repairing stripped threads with JB Weld

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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.

Re: repairing stripped threads with JB Weld

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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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Re: repairing stripped threads with JB Weld - where's the bolt??
Nick Müller wrote:
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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

Re: repairing stripped threads with JB Weld - where's the bolt??
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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...



Re: repairing stripped threads with JB Weld - where's the bolt??
Emmo wrote:
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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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Re: repairing stripped threads with JB Weld
On Sat, 24 Dec 2005 11:47:54 +0100, muellernick@gmx.de (Nick Müller)
wrote:

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

Re: repairing stripped threads with JB Weld
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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!



Re: repairing stripped threads with JB Weld
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
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before,
to
pull
already



Re: repairing stripped threads with JB Weld
Won't work, you're screwed!




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Re: repairing stripped threads with JB Weld

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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.



Re: repairing stripped threads with JB Weld
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!



Re: repairing stripped threads with JB Weld

"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.



Re: repairing stripped threads with JB Weld
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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!



Re: repairing stripped threads with JB Weld
On Sat, 24 Dec 2005 16:33:58 GMT, "Leo Lichtman"

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Permatex and LocTite are the same company.

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