Question re: epoxy thread repair


Technical information and Q&A applicable to all years and models of Goldwings
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mytown
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Question re: epoxy thread repair

Post by mytown »



I stripped a bolt hole on a CX650C engine, see here:


The bolt (M8x55mm, fine) goes through the body of the head and into the block but it's not a head bolt. It's used to secure the thermostat housing bracket. I don't know the condition of the motor so I plan on trying a fix using Loctite Thread Repair, basically a 2 part epoxy. Will I be able to later pull the head, drill the epoxy out and re-tap so as to fit a larger bolt or a helicoil? Any thoughts appreciated.


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Mh434
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Re: Question re: epoxy thread repair

Post by Mh434 »

Personally, I'd start with the helicoil (or, if there's enough meat in the castings, simply tap it out to the next largest metric size, and use a larger bolt). I wouldn't trust epoxy for a repair like that, no matter how good it sounds on the packaging. As far as metal & engine repair expoxies go, J B Weld is generally considered the go-to stuff.

If you decide to use epoxy, and don't want the bolt to be permanently glued into the engine, you might try to apply a thin coating of NeverSeize or oil onto the bolt before putting it in place...
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Bluewaterhooker0
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Re: Question re: epoxy thread repair

Post by Bluewaterhooker0 »

I'd vote for tapping the hole, or using a helicoil from the get-go. Epoxy has its limits, especially where grease and oil are present.
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mytown
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Re: Question re: epoxy thread repair

Post by mytown »

Thanks for the replies.
I've been looking into using a helicoil. Given the way the hole is situated, the drill bit and the tap in the 8M x 1.25 helicoil kits are too short to allow for being turned. It looks like I'll need an extra long 21/64" bit and a Lisle #5 tap socket so I can use a socket wrench with an extension when I tap the hole. There's also the issue of having a long enough coil insertion tool, although It looks as though the ones in the 8M x 1.25 kits might work. What I'm wondering now is what next lager size bolt could I use if I decided to just drill out the hole and tap new threads for a larger bolt. Seems like even a standard size could be used in this case.


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