Seized AN Fitting

[slowflyin]

All,

I’m working on an AEIO320 with an AN822 -8N fitting that is seized in the accessory case.  I’ve tried all the usually tricks while practicing the “do no harm” doctrine.  

Over the past couple of days I’ve been applying penetrating oil, tapping, heating….. No luck.   Hoping someone can offer a path forward.  Thanks in advance.  

Happy Thanksgiving!  

 

[takair]

I have a sniffle valve in my sump that is similar.  I’ve tried everything in situ…but I fear snapping it since the next step is drilling and that requires more disassembly.  Often the problem is the flats strip first.  Are the flats already stripped?  Can you sacrifice with vice grips and heat?  Got picture?

[PT20J]

My IA swears that for stuck parts where nothing else works he uses a 50-50 mix of Stoddard solvent and Dexron ATF and lets it soak overnight. 

[A64Pilot]

If I understand your dealing with a pipe fitting so penetrating oil, won’t.

Heat as in heat gun not torch has been my best thing to try, stupid as it sounds but slightly tightening sometimes works but I don’t know why but working it tightening then loosening when it’s hot may help.

 

[A64Pilot]

1 minute ago, PT20J said:

My IA swears that for stuck parts where nothing else works he uses a 50-50 mix of Stoddard solvent and Dexron ATF and lets it soak overnight. 

There is actually a lot of evidence that a mix of acetone and ATF is the best penetrant. I’ve always alternated heat and liquid wrench myself, but is what he has pipe threads?

[slowflyin]

Thanks for all the replies.  Yes, it’s a 45 with a flare on the hose end and pipe threads on the case side.   Flats are still good.  3/4 end wrench has just a tiny amount of play.  

[Fly Boomer]

2 minutes ago, slowflyin said:

3/4 end wrench has just a tiny amount of play.

Use a box-end if you can.  Open-end wrenches seem to do more damage on tight fittings.

[slowflyin]

1 minute ago, Fly Boomer said:

Use a box-end if you can.  Open-end wrenches seem to do more damage on tight fittings.

Can’t get it around the corner unfortunately.  I’ll try a low profile wrench.  

[EricJ]

22 minutes ago, slowflyin said:

Can’t get it around the corner unfortunately.  I’ll try a low profile wrench.  

A good (well-fitting) crow's foot on a breaker bar with a cheater pipe.    That let's you apply a lot of steady torque and still feel it yield.   Assuming there's space to do that, anyway.

[47U]

2 hours ago, slowflyin said:

I’m working on an AEIO320 with an AN822 -8N fitting that is seized in the accessory case.  I’ve tried all the usually tricks while practicing the “do no harm” doctrine.

13 minutes ago, EricJ said:

A good (well-fitting) crow's foot on a breaker bar with a cheater pipe. 

EricJ is right.  A 6-point crow’s foot would be the best option.  Along with the heat and penetrating oil suggestions.  Is corrosion suspected?  If so, Kroil (Aero Kroil) is my go-to penetrating oil.

[A64Pilot]

Corrosion may not be visible, but it’s almost certainly the cause, why else would it seize?

Penetrant can’t hurt so certainly give it a try, but I suspect as pipe threads are an interference fit that nothing will penetrate, not allowing a leak is of course what pipe threads are for. But it can’t hurt and maybe it might get into a thread or two and who knows maybe that’s the straw?

Often significant heat will break loose that corrosion bond. I’d try a heat gun first and after trying everything else first graduate to propane. Idea is to heat only the fitting causing it to expand or try to anyway and that might break the corrosion bond. Try getting it to wiggle just a tiny by tightening and loosening, just trying to get it to wiggle.

Let it cool completely and try again with it cool.

I’d honestly go ahead and order the fitting and use a vise grip myself, squeezing the snot out of it may even help it break free, it’s a hollow part after all. 

In the Army we would use liquid Nitrogen sometimes to shrink a part to get it to let loose, but that may be beyond your capabilities, but maybe your local Airgas of whatever has a small dewer like Dr’s use they will rent? Never asked myself.

Edited November 28, 2024 by A64Pilot

[slowflyin]

All, thanks again for the comments.

I concur penetrants and pipe threads are a long shot at best.   No joy with the 6 point crows or line wrench.  Just not enough room.  I’m going to give heat a try.  I’m not really concerned about the fitting.  I have another.  More concerned about the accessory case.  If corrosion is the issue there is no way to tell what will give first.  Odds are it will be the fitting.   Low probability the threads will be damaged in the case but if they are it won’t be a good day.     

[PT20J]

I might call a couple of overhaulers - they must run into this often and may have some tricks. 

[slowflyin]

36 minutes ago, PT20J said:

I might call a couple of overhaulers - they must run into this often and may have some tricks. 

Great advice.  Will do.

[N201MKTurbo]

Nickson’s machine shop, which rebuilds cases. Told me they have a guy that can get any fitting loose. It might be worth a call. Talk to Rudy.

[Yetti]

Stilson wrench.   Last fitting I had to get out was I used a dremel to cut a slot for a big screw driver to get them out.    Someone ran the air tank drains on the LMTV into a tree.    The final way is a diamond bit on a dremel tool and take it out a little at a time after you snap it off with the Stilson Wrench.

[N201MKTurbo]

11 hours ago, Yetti said:

 Stilson Wrench.

I don’t think anybody calls it that any more….

[DonMuncy]

I still do. Tells you something about me.

[N201MKTurbo]

1 hour ago, DonMuncy said:

I still do. Tells you something about me.

So, you still have the one you bought in 1865? 

[DonMuncy]

5 minutes ago, N201MKTurbo said:

So, you still have the one you bought in 1865? 

No, but I have tools I got in 1955

[dzeleski]

Depending on access....

I have had a lot of luck using a torch or heat gun depending on the surface sensitivity, and then ice or dry ice on the fitting itself. If the fitting is pointed down you can super cool some water by filling a cup with ice, put a tablespoon of salt in and then fill the rest with water and stir it up. Then just put the cup on the fitting. Keep heating the outside surface while you keep the fitting cold and then quickly try and remove the fitting with a good tool that has a good grip on the fitting. Dry ice is easier to get into strange places though because its not constantly making everything wet.

Edited November 29, 2024 by dzeleski

[slowflyin]

Quick update- It’s out!  Three days of heat cycles, penetrant, tapping, and rocking back and fourth finally did the trick.    Thanks again to all that offered such great advice.

[A64Pilot]

1 hour ago, slowflyin said:

Quick update- It’s out!  Three days of heat cycles, penetrant, tapping, and rocking back and fourth finally did the trick.    Thanks again to all that offered such great advice.

I like a happy ending

[Yetti]

On 11/29/2024 at 9:33 AM, N201MKTurbo said:

I don’t think anybody calls it that any more….

don't disparage my grandfather.   "Right tool for the job"   In other news google searches for Stilson Wrench are up by 40

[EricJ]

Still used as a murder weapon in Clue, too.