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Discussion Starter #1 (Edited)
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The helicoil insert came out with the bolt as I removed the bolt to remove the trans mount and add the Powerflex insert.

This stripped our the bolt and the accepting upper mount.

I have already ordered the bolt from the dealership, but would like to order a self-tapping thread insert so I can install it the moment the bolt arrives.

Does anyone know the specifics of the bolt? I believe the bolt itself is an M12 size but don’t know the thread pitch.

Any help in the bolt specifics and where to source a proper thread insert would be appreciated.
 

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The thread pitch is going to be fine thread (12mm x 1.25), or super-fine (12mm x 1.50) but I don't know where you would find a self-tapping thread insert. McMaster Carr sells some for aluminum but not in the correct size.
Also, depending on the damage to the hole a special oversized repair heli-coil insert may be needed. McMaster Carr does sell the correct sized fine or super-fine heli-coil but you will also need the tap and the insertion tool.

Since you don't really seem to know what you are doing - I don't mean to be rude but since you don't know the thread pitch of the bolt - you probably shouldn't be on your back under the car trying to re-tap the hole and then thread in the heli-coil insert.

I've regularly insert heli-coils with a few different sized old flat head screw drivers which I have modified for the task but I was once a machinist. I would strongly suggest you seek professional help before you do more damage to the car. Right now it may be possible to only have run the heli-coil tap back through the hole and set the insert in some Loctite and then re-install the mount. But, if you cause any further damage to the hole it may have to be welded up before it can be re-threaded and re-inserted.

Just to be a good guy, are you anywhere near Hampton Roads Virginia? For a decent lunch/dinner or maybe a good bottle of single malt I could be persuaded to make a house call. I've been a member of the AROC for over 35 years and I do ALL of my own maintenance to my collection of Alfas, Fiats, Ferraris and daily drivers.
 

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I was thinking, we have a BIG Ace Hardware a couple of miles away and they have an extensive collection of Hei-coil inserts and matching taps in-stock and on the shelf. The tap isn't cheap ($25.00 - $30.00) relatively speaking, because they are not useable for anything other than thread inserts because they are odd-ball sizes... But, they did have the correct size in stock when I re-did the spark plug hole in a friends cylinder head. Worth a look/try...
 

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Discussion Starter #4
@MultiAlfaOwner

Thank you for the insight. I appreciate the offer and would gladly accept, but I’m on the West Coast in the Greater LA/OC area.

Heeding to the advise from MultiAlfaOwner, does anyone know a mobile professional w/ the experience in these matters in my area?
 

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Worth a look/try...
I agree.

Judging from the photo, even the bolt looks relatively unscathed. Hopefully, Alfa has already has bolt somewhere in North America.

However, if looking at a long wait, I think whatever damage the bolt incurred the could probably be undone with a 12mm die - after determining the correct thread pitch of course. 12mm fine is 1.25. Course is 1.75. (I‘m guessing Fine).

It sucks when a 1 or 2-hour project turns into a weeklong kerfuffle, but the damage looks very minor, relatively easy and inexpensive to repair. Good luck!

BTW, I’m getting ready to install the same bushing. Now thinking about putting a dab of anti-seize on my bolt in hopes of avoiding this issue in the future.
 

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Discussion Starter #6
@ “ BTW, I’m getting ready to install the same bushing. Now thinking about putting a dab of anti-seize on my bolt in hopes of avoiding this issue in the future.”

I recommend using a good amount of anti-seize on the bolt before attempting to break it free. In speaking w/ a tech at a local Alfa/Maserati dealership I was told that all techs at Alfa/Maserati use a liberal amount of anti-seize spray on most large engine and suspension bolts to prevent problems like the one that I now have.
 

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From the TechAuthority Service Manual... hope this helps.

 
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Discussion Starter #10
I just noticed the odd size indicated on the document provided by Docron:
M12x1.72x95.

@MultiAlfaOwner or anyone else w/ experience:
Is this a possible typo from Alfa, or is there such a thread pitch as 1.72?

In my research I’ve seen 1.25, 1.5, 1.75 and even 2mm thread pitch, but never increments other less/more than 5mm.

If in indeed 1.72 is correct, is it because it is a stretch bolt?

Also, is a threaded insert or 1.72 commonly available, or will the 1.72 bolt fit in a 1.75 thread?
 

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I'm a QA Manager and I have immediate access to a world of specs. Nothing and I mean NOTHING shows a 12mm x 1.72. It is a typo and it should be super-fine thread 12mm x 1.75. Heli-coil brand inserts are readily available and just for my own amusement I went to Ace Hardware and looked for either 12mm fine or 12mm super-fine inserts and believe it or not they had both in stock. I was really surprised...

I would go on-line to someplace like Fastenal and order the parts there.

For the record, when I did mine mount I stripped out one of the inserts for the belly pan so I sprayed all of them with PB Blaster before I took any of the others out. I liberally coated everything with C-5A anti-seize before I put them back. Really like the difference in the feel of the mount.
 

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A bit off topic, but since this thread's delved into anti-seize I thought some might find this little factoid interesting/amusing - though I'm not advocating it for our 4Cs!

During overhaul, AMTs (aircraft maintenance techs) coat hot-section jet turbine parts with Phillips' Milk-of-Magnesia before reassembly. Pratt & Whitney and GE even have a part number for it - the unflavored version obviously. ("GE J79 Engine Manual Chapter 72-55-05 Paragraph 2B, Milk of Magnesia item #C02-061.").

Regarding anti-seize for autos, I suspect such a topic could go downhill as quickly as an oil thread but, FWIW, for any electrical part going to ground (like an O2 sensor) I was taught to use a copper-based compound for its superior conductivity (second only to silver), and to use nickel and/or aluminum-based compounds on everything else for their enhanced resistance to corrosion, better long-term stability, and higher heat resistance.

If price is no object, or as in my case you have a friend that works at in industrial supply house and can pass along their employee discount, Bostik V074940 Never-Seez is the best stuff I've found.

It is literally a MIL-A-907-SPEC Nuclear Grade anti-seize - "specially tested and certified pure for use in nuclear power plants." Temperature Range/Rating: -297°F to 2400°F
 

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Discussion Starter #14
I’ll continue bumping and in hopes that a forum member can recommend someone in Southern California that has experience in tapping, inserting helicoils AND is mobile.
 

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That is cool! I had no idea "mobile thread repair" was a thing - mind saying approx what that service cost?
 

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Discussion Starter #17
That is cool! I had no idea "mobile thread repair" was a thing - mind saying approx what that service cost?
I was charged $175–the minimum this company charges for a visit.
The work on the 4C took about 45minutes and Eric even helped me install the motor mount w/ insert and tighten to torque specs to reassure me that the new helicoil was in there properly.
It took about 1 1/2 hours for the work on the Jeep—and again he had me tighten to torque specs in his presence for reassurance.
 

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Thanks, very reasonable for the services provided - I bet he stays busy!
 
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