strip bolt question

I have a bolt(12m 1.25) that connects the engine mount to the
transmission( it's one of three bolts) on an 89 Civic hatch,5spd, that can
no longer be torqued. I initially re-threaded the bolts and cleaned out the
thread hole with the re-thread tool. But it's a no go.

I am tempted to find an oversize bolt, but before I do, is there another way
to go?

thanks in advance

Gary

 

If the threads are gone you have no option for repair other than making the
hole bigger. You have to make the hole bigger to put a heli-coil in. Then
you can use the same size bolt as stock.

 

But how much trouble could I get into by simply using an oversized bolt or
even rethreading the case to the oversized bolt? The bolt size is a 12m 1.25
and is about 2 inches long. I tried Napa and Carquest and they were useless.
But I went to Ace hardware and they had a 1/2 20 (non metric)bolt that
matches the threads and is just slightly larger in diameter. I am so tempted
to get a 1/2 20 tap and tap out the hole to match the new bolt. Would that
even work?

thanks in advance

Gary

 

Your could use a HeliCoil to repair the threads back to original size.

My opinion is that tapping out to 1/2 20 would also work OK.

 

I agree with you on that.

The process of putting in a helicoil is the same as putting in an oversized
bolt.

The thing is both methods require the hole be drilled to a certain size and
both methods require they be tapped with the correct tap.

I prefer to use the same bolts that came with the car and If I am doing the
same amount of work I would just as well utilize a helicoil for the original
bolt. The threads would be stronger than the original (assuming aluminum
originally)

CaptainKrunch

 

||I prefer to use the same bolts that came with the car and If I am doing the
||same amount of work I would just as well utilize a helicoil for the original
||bolt. The threads would be stronger than the original (assuming aluminum
||originally)

No argument there, but in this case it sounds like the stripped hole is somewhat
inaccessible. That is, the bolt goes through the engine flange (?) and then into
the transmission case, which is (was) threaded. So properly inserting a
helicoil might be next to impossible. I assume the HC tap is bigger than the
nominal diameter of the fastener, and you do not want to tap the engine flange
hole that the bolt slides through. That same flange hole would also make it
harder to start the HC, especially using the short plastic insertion tool. At
the least it would require the larger steel tool from the pro kits.
Doesn't sound like much fun, which is why I suggested he consider JB Weld
and a stud. With that in place, if the engine and transmission are separated in
the future, a torch on the stud would free it from the JBW and leave the
original hole available to a proper Helicoil repair.
Texas Parts Guy

 

I sure hope it is 12 mm, not 12 m! You probably meant M12 x 1.25 mm,
which is 12 mm.

The threads do not really match. 1/2" 20 is 1.27 mm, not 1.25 mm thread
(or conversely, 12 mm 1.25 is 20.32, not 20 pitch).

I would worry about the load rating on the bolt from ACE. If you put in
a non-Honda bolt, make sure it has a load rating at least as high as the
original bolt.

As others have said, since you are going to have to drill and tap
regardless of going over size bolt or going helicoil, I'd go helicoil
and use the original bolt.

 

The Helicoil sounds like that is the true way, but it sounds like I'd have
to pull the transaxle for that. I just re-did the clutch. There is another
system( I read about) out there called "Time-sert" that seems as good if not
better than the Helicoil and it doesn't seem to require removing the tranny
to do it. Any experiences with Time-sert?

But I really liked the suggestion of using JB Weld to put in an M12 1.25
stud instead. This is just an old 89 Civic with 142k miles on it. But it's
in beautiful condition so I do plan to keep it till it stops
running......but with a little good fortune, I hope to not have to pull the
tranny again as long as I own it.

Any thoughts about Time-sert or JB Weld??

thanks

Gary