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Bolt identification help


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Need some help.  My IA just found a bolt on the main gear that has the safety wire slowly cutting it in half...  Picture below.

We are going to replace the bolt but the parts manual is confusing me a bit.  There are multiple bolts listed.  It lists AN part numbers and Mooney part numbers.  Are they the same?

1966 E Model

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Something to consider...

For a wire to cut into a piece of metal....

There would need to be some rubbing motion.... or serious vibration...

It isn’t very likely that safety wire gets much motion...

Look extra closely to see what else may be going on.  Or how loose the safety wire is...

PP thoughts only, not a tribologist...

Best regards,

-a-

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1 hour ago, RLCarter said:

I thought the “A” at the end of an “AN” bolt meant there was no hole, I don’t think mine are drilled for safety wire, will try and remember to clean them out tomorrow 

The H means the head is drilled, the A at the end means there is no hole in the threaded end for a cotter pin.

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I doubt that the soft stainless steel safety wire cut through the steel bolt.  Either the bolt head has been ground thinner, exposing the hole, or someone has drilled their own hole through the bolt.

Clarence

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Aircraft Spruce has this aid for bolt selection:

https://www.aircraftspruce.com/pages/ha/bolts/anbolts.php

Also helpful for AN dummies like me:

https://www.experimentalaircraft.info/articles/aircraft-building-2.php

 

Edited by Mooneymite
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1 hour ago, M20Doc said:

I doubt that the soft stainless steel safety wire cut through the steel bolt.  Either the bolt head has been ground thinner, exposing the hole, or someone has drilled their own hole through the bolt.

Clarence

I'm glad to hear you say that.  I was thinking the same thing.  I'll clean the area really wall today and see what evidence shows itself.

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7 hours ago, carusoam said:

There would need to be some rubbing motion.... or serious vibration...

Look extra closely to see what else may be going on.  Or how loose the safety wire is...

The prop is in need of balancing but its not that bad...  The gear door hung a little lower than it should but no sign of abrasion on the skins. 

It looks like Spruce and Lasar have the bolts.  I'll order one up.

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Now that you all helped me identify the bolt, any tips on how to replace it?  It looks to me if I release the gear just a bit, until the link goes back overcenter and releases the preload, I should be able to remove the bolt.  Doing this would leave the other 2 connections of the retract truss in place and I could realign it by moving the J bar or main gear until the hole lines up and the bolt is inserted.  Thoughts?

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With the plane on jacks.

Release the J bar and let it go to the 45 degree position. remove the rod from the little swing arm to the retract mechanism. This will remove all pressure from the retract links and you will be able to swing the gear by hand. Then remove the two bolts and slide the bracket off.

If it was me, in for a penny, in for a pound. I would take all the retract links apart, clean, inspect, paint and reassemble.

None of this should affect your preloads, but it is always a good idea to check just to make sure you didn't screw anything up.

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2 hours ago, N201MKTurbo said:

Then remove the two bolts and slide the bracket off.

If it was me, in for a penny, in for a pound. I would take all the retract links apart, clean, inspect, paint and reassemble.

None of this should affect your preloads, but it is always a good idea to check just to make sure you didn't screw anything up.

I'm assuming there are nuts beheld these 2 bolts that I access from an inspection panel? 

I've got a few other discrepancies from the annual so I really don't want to be in for a pound on this one... but oncy I'm doing the work I'm sure I'll want to clean and paint everything.

I just bought a set of preload tools so I'll certainly be checking them.

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3 hours ago, flyingchump said:

I'm assuming there are nuts beheld these 2 bolts that I access from an inspection panel? 

I've got a few other discrepancies from the annual so I really don't want to be in for a pound on this one... but oncy I'm doing the work I'm sure I'll want to clean and paint everything.

I just bought a set of preload tools so I'll certainly be checking them.

It’s been a while since I had one of those apart, but I think there nut plates.

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16 hours ago, N201MKTurbo said:

I would send a picture, but I can’t hold the flashlight, inspection mirror and phone at the same time. 

I thought to be an A&P / IA you had to be a contortionist with a third hand and that the magic wand and crystal ball was optional   :) 

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On 2/19/2021 at 8:12 PM, flyingchump said:

We are going to replace the bolt but the parts manual is confusing me a bit.  There are multiple bolts listed.  It lists AN part numbers and Mooney part numbers.  Are they the same?

Already corresponded with flyingchump about this, but for others reading the thread... the reason multiple bolts are listed with "AR" is that the length of bolt you need depends on how your particular hand-crafted aircraft came together at the factory.  The spacing between the retract link and the "tension strap" (the thick piece of aluminum riveted to the spar structure) varies from airplane to airplane, so shims are inserted into the assembly as needed to make everything match up.  The length of bolt you need to snug things together depends on the number of shims.  The "AR" in the parts manual just means (A)s (R)equired.  In other words, you have to take the old bolt out to figure out what length you need as a replacement.

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On 2/21/2021 at 8:06 AM, N201MKTurbo said:

If it was me, in for a penny, in for a pound. I would take all the retract links apart, clean, inspect, paint and reassemble.

I did this a couple of years ago due to slop in the bolts/bushings.  There's a thread on it here: https://mooneyspace.com/topic/25238-replacing-over-center-link-bushings-to-re-establish-clearance-to-main-gear-trusses/

I removed the entire main gear to do the work.  I don't think it's possible to completely remove all the retract links without doing so, because the main gear truss interferes with the removal of one of the bolts, no matter where you position it in the swing cycle.  Someone with more experience may have a trick, but I couldn't find one.

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59 minutes ago, Vance Harral said:

I did this a couple of years ago due to slop in the bolts/bushings.  There's a thread on it here: https://mooneyspace.com/topic/25238-replacing-over-center-link-bushings-to-re-establish-clearance-to-main-gear-trusses/

I removed the entire main gear to do the work.  I don't think it's possible to completely remove all the retract links without doing so, because the main gear truss interferes with the removal of one of the bolts, no matter where you position it in the swing cycle.  Someone with more experience may have a trick, but I couldn't find one.

You are probably right, I know the bolt you are talking about. I’m trying to remember if I ever took it out without removing the whole leg.

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Thought I'd report back.

I received a new bolt from Lasar and swapped it out.  Super easy!

Dan sent me a NAS6606H21.  It has a slightly different head but it was better for lockwireing.

After jacking up the plane I released the J bar about 3 inches (held with a bungee cord).  I removed the old bolt which was barely tight... Once the bolt was removed everything stayed exactly in place.  I cleaned up the area and slid in the new bolt with a slight wiggle of the main gear.  Safety wire and done!  Super easy.

My IA will stop by to check my safety wire and preload in a few days.  

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