Inspect wing attach bolts?

[Ragsf15e]

So a couple years ago at a well known msc, the IA noted “light corrosion at wing attach bolts, cleaned, applied acf50.”  

I’m now in a very dry climate, stored in a hangar, but occasionally fly in rain or stay overnight near the rainy coast.  And I’m always anxious about corrosion on a 51 year old airplane.

If I wanted to inspect the area again and/or apply an acf fog, how to I get there?  From the cabin down or up from the belly?

[N201MKTurbo]

You have to remove the strips between the wing and fuselage. You need to remove the interior side panels. Most of the screws have #4 tinnerman nuts that will fall off if you just unscrew the screws. With the interior and strips off you will be able to see all the attach bolts. They often get a bit rusty because water gets under the strips. Before you replace the strips replace the tape over the gap. The tape keeps the water out. I have found that the adhesive fails on aluminum tape, so I put on aluminum tape and then a layer of high quality duct tape. Between the two it seems to last forever.

[Ragsf15e]

1 hour ago, N201MKTurbo said:

You have to remove the strips between the wing and fuselage. You need to remove the interior side panels. Most of the screws have #4 tinnerman nuts that will fall off if you just unscrew the screws. With the interior and strips off you will be able to see all the attach bolts. They often get a bit rusty because water gets under the strips. Before you replace the strips replace the tape over the gap. The tape keeps the water out. I have found that the adhesive fails on aluminum tape, so I put on aluminum tape and then a layer of high quality duct tape. Between the two it seems to last forever.

Thanks, so from the interior side panels, then “strips” (I’ll have to find these, not sure what they are), then see down?

Thanks for the heads up on tape and the nuts!

[N201MKTurbo]

2 minutes ago, Ragsf15e said:

Thanks, so from the interior side panels, then “strips” (I’ll have to find these, not sure what they are), then see down?

Thanks for the heads up on tape and the nuts!

The strips are the little fairings that run between the wing and the fuselage. They are outside the plane.

[Guest]

This might help.

Clarence

[Ragsf15e]

Jeez, that does help!  I was picturing vertical bolts,  appears they’re horizontal, aligned both fore/aft and laterally in line with the wing.  Thanks!

Rags

[Ragsf15e]

Ok, so I inspected them at annual and the nuts are lightly rusted, bolts good, sprayed LPS 2 on them, IA wasn’t concerned.

But holy cow, the tape that “seals” below that outside wing/fuselage trim piece was 50 years old and turning to dust.  My IA had me use duct tape and that nasty black 3m caulk strip to seal under the trim, but the caulk strips are a little thick to fit under there.  The trim isn’t quite flush.

How is that supposed to be sealed??  Seems like those attach bolts would see a constant stream of water with any precip.

Maybe 3M 50 tape?

[Shadrach]

9 hours ago, Ragsf15e said:

Ok, so I inspected them at annual and the nuts are lightly rusted, bolts good, sprayed LPS 2 on them, IA wasn’t concerned.

But holy cow, the tape that “seals” below that outside wing/fuselage trim piece was 50 years old and turning to dust.  My IA had me use duct tape and that nasty black 3m caulk strip to seal under the trim, but the caulk strips are a little thick to fit under there.  The trim isn’t quite flush.

How is that supposed to be sealed??  Seems like those attach bolts would see a constant stream of water with any precip.

Maybe 3M 50 tape?

We used aluminum tape but when I do it next I’ll use duct tape because it’s more flexible.  I think LPS 3 is a better choice for this application. 

[Mooneymite]

You might want to do step 15 of SB 208B while you're inspecting wing attach bolts:

 

 

15.  Remove tension bolts from fitting/spar at tach point, LH side - then RH side. Care-fully pass a small pencil magnet on a long flexible shaft up through threaded portion of tension fitting and into tube interior at least 12 - 15 inches, with draw magnet and observe if any metal (rust flakes) adhere to the magnet. Bright metal, indicating no
corrosion, should be on the magnet along with rust flakes (if any).
Repeat this process until rust flakes are removed. When all metal (if any) is pulled from the tube, spray moisture displacement fluid, ie., LPS-1, through tension fitting into the interior of the tube, both sides of the air craft.

 

[Ragsf15e]

14 hours ago, Shadrach said:

We used aluminum tape but when I do it next I’ll use duct tape because it’s more flexible.  I think LPS 3 is a better choice for this application. 

Agreed.  Didn’t have any on hand, so I ordered lps3 and some really good duct tape.  Gonna go back in and do it right.

[Ragsf15e]

14 hours ago, Mooneymite said:

You might want to do step 15 of SB 208B while you're inspecting wing attach bolts:

 

 

15.  Remove tension bolts from fitting/spar at tach point, LH side - then RH side. Care-fully pass a small pencil magnet on a long flexible shaft up through threaded portion of tension fitting and into tube interior at least 12 - 15 inches, with draw magnet and observe if any metal (rust flakes) adhere to the magnet. Bright metal, indicating no
corrosion, should be on the magnet along with rust flakes (if any).
Repeat this process until rust flakes are removed. When all metal (if any) is pulled from the tube, spray moisture displacement fluid, ie., LPS-1, through tension fitting into the interior of the tube, both sides of the air craft.

 

Ok, so let’s say I did this, could I then replace the slightly corroded nuts and/or bolts?  Do you know part numbers and wherr to find em?  Hopefully not from the factory...

[Andy95W]

For SB 208, they're standard bolts, so you could order them from Aircraft Spruce.  For the other bolts, they're all spelled out in the parts manual.

 

[Hradec]

17 minutes ago, Andy95W said:

For SB 208, they're standard bolts, so you could order them from Aircraft Spruce.  For the other bolts, they're all spelled out in the parts manual.

 

My 1964 m20e IPC calls for AN7H-16A

Tension bolts, and that is what was installed. What am I suppose to reinstall? 

[Andy95W]

You should use the parts called for in the Parts manual.  The bolts themselves are standard AN parts with no differentiation for "tension" bolts.  They're all the same.  

Later years might've been drilled/tapped differently, or had a slightly thicker spar at the attach point.  That may be why they're a touch longer.

[Hradec]

Lasar carried both lengths, they were really cheap, lasar was out of stock, checked mooney, they had both lengths and much cheaper. Just got them last week.

Dont forget the thin washers

Glenn

[Ragsf15e]

17 hours ago, Hradec said:

Lasar carried both lengths, they were really cheap, lasar was out of stock, checked mooney, they had both lengths and much cheaper. Just got them last week.

Dont forget the thin washers

Glenn

Thanks, good info.  So you did this or had it done?  I’d like to get rid of my slightly rusty brownish nuts on the wing attach bolts.

was it fairly straightforward?

thanks!

[Hradec]

I'm doing sb208 insulation and tubing corrosion sb. Bolts looked rough so I am replacing the bolts. Wing nuts not part of sb, but if mine look rough, I will change them.

Doing this myself. First time aircraft owner, halfway through getting my pilots license, I'm an a&p with very little GA experience. Lots of work to do on my 64 m20e that hasn't flown in 5 yrs

Edited December 28, 2019 by Hradec
Typo, add more info

[carusoam]

Hrad...

Consider adding some data to your avatar area...

Having the A&P is great!

But every time you mention changing something like a wing bolt... somebody is going to forget you have the skill and the training... to go with that...

Often we will see a new MSer thinking swapping out some hardware is OK because they have done it on more critical machines at work...

we have plenty of wing nuts around here...

https://www.shutterstock.com/image-photo/metal-wing-nuts-isolated-on-white-249023413

Best regards,

-a-

[Hradec]

Doing all by the book. Traceable hardware, calibrated torque wrench, proper safety wire, and all I am doing is the cage tension bolt, not a wing attach bolt. Lots of people trying to play mechanic with good intentions......

Glenn

 

[carusoam]

Throw up some pics if able...

Best regards,

-a-

[RobertGary1]

On 12/26/2019 at 4:53 AM, Shadrach said:

We used aluminum tape but when I do it next I’ll use duct tape because it’s more flexible.  I think LPS 3 is a better choice for this application. 

Duct tape holds moisture and encourages corrosion and molding. Its why its not legal for HVAC systems any more. Aluminum tape solves this.

-Robert