Spark plug change.. secondary Air Injection Tube stud broke

Oh, yeah you can... There's broke and there's made it worse broke...

 

Weld a washer to it
then weld a nut to the washer
then put a wrench on the nut and it will come out easy

 

Almost precisely the same thing happened on mine, except the rear/upper 10 mm nut came off all right.

Driver's side, lower one. Sheared off precisely the same and I had pre-treated the stud and nut with the usual stuff.

Someone asked if there's a nut behind the flange - no, the stud is just set in the flange.

What I did was, reinstall the upper thingie at the good end, (for bit alignment purposes) then drill out the stud. I had a nut, washers and bolt in my junk box (which happened to be Imperial but OK). I used some of that cherry red Anaerobic sealant, just to be on the safe side.

Just wish I had installed new Ignition Coils right then and there - I've got to do that soon.

I wonder what is getting on this hardware - or did the connection get corroded in large part because of the proximity to the manifold.

Note: Change plugs often, then the connection will not get a chance to corrode so much. Salt on Roads? Clean and protect this hardware.

You will need an articulating "snake" adapter to get your drill/driver in a good spot to drill out the busted stud.

 

That thought never left my mind, until I was almost done!

+

Oh, btw, the repair has 10,000 miles on it - no codes.

 

This is why i anti seize everything. Drill baby drill. Get good drill bits and don't break any. Start small and work your way up, will most likely come out before damaging the threads.

 

Well, persistence prevails. Cut the stud flat with the flange, and drilled it out with a set of hex bits from Amazon (superb quality!) and using a 12” hex bit extension. Could have probably re-taped the threads but opted for just a bolt and nylon lock washer (replaced the one after taking the photo). Drilled it out to 1/4” and then installed a M6x30 bolt with washer and lock nut.

 

Good job! But I don’t think you should be using a nylon locking hardware. It will probably melt due to high exhaust temperatures. I’m not sure where you would source it but, in aviation, there are stainless lock nuts available that do not rely on a nylon insert. These are used on engines and other areas that are exposed to high temperatures.

 

Well done sir. I concur, nyloc is not the best on your application.

 

@TheSponge if you don't have a source for an aviation grade steel self-locking nut, let me know. It won't be metric threads though, so you will need a 1/4-28 threads per inch bolt to go with the nut.

 

Don’t have access to an aviation store. Googled this aviation nut to see what it looks like but the results are all over - anyone have a photo of which nut is being referred to here?

Worst case I’ll just install the nut I had on there lol. I also had a M6 but that had a built in washer but it spun on the nut itself.. not quite sure what those are for!?

 

DM me and I will help you out. I have plenty of aircraft hardware.

 

This is what it looks like. Top of the nut is ovalized to put a squeeze on the threads. Aircraft hardware in North America is 99% in debt slavery units, not metric, so you'll need a 1/4" bolt: https://skygeek.com/mil-std-ms21042-4-nut.html Better off just using a regular hex nut and lock washer:

 

For what it is worth, the Anaerobic red sealant I used is not getting discolored or anything., from heat. I don't think the fasteners or the join looks any different after well over 1,000 miles. Remember that only one of the two connections here is compromised, and nothing dramatic is going to happen if the replacement nut and bolt were to fail. There's no reason this replacement connection would loosen more than the stock connection it replaces. Easy as she goes. This fix is so much better than just carrying on without anything holding this side of the flange together.

 

Interesting stuff at SkyGeek

 

Excellent resolution! Mind posting a pic of what you used to drill out the stud?

I also agree nylon locknuts are going to melt. The split washer idea is better. Your local hardware store should have a decent selection of stainless bolts, nuts, and split washers. Using stainless hardware would be ideal given the fact it’s a high heat application (even if the hardware store variety is not the best stainless alloy).

 

I’ll look at installing a split washer and regular nut. Worst case the nylon stuff melts, at least now if it were to snap, that bolt is not threaded into the flange and will just fall out from below. I did coat with copper antiseize. Better than using one of those clamp solutions!

For those asking on the parts,

These are the bits I used - https://a.co/d/cRzuraA

12” Hex Extension. I’m returning the extension as it had issues holding the bit, so if your Canada don’t buy the one from Princess Auto. But the 12” was perfect as it put the drill near the brake fluid reservoir and the angle was also perfect to drill into the flange. https://www.princessauto.com/en/12-...020&gbraid=0AAAAADu8PlP4RX5kBoE5-vEIxkhCMbHCl

 

After making this awesome repair, Move forward with adding https://www.mcmaster.com/ into your library of resources if you do not already have it.

 

Oh I’ve heard of McMaster, being in Canada since I am not a business or School is very costly.. great catalog tho! With lots of