How To Fix Corrosion on Landing Gear?

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reecewallace
Posts: 165
Joined: Tue Jan 05, 2021 1:34 am

How To Fix Corrosion on Landing Gear?

Post by reecewallace »

I have some corrosion on the landing gear of my 170b.

What steps are involved to fix this? Sand, corrosion inhibitor, prime, paint?

If anyone is able to lay out the exact steps and products I need to do this, I'd greatly appreciate it. I'm inexperienced and this is my first time fixing corrosion.

Also, you can see from the photo there is a brake line bracket clamped to the landing gear. How do I remove this? I'm assuming it's JB welded to the gear—heat gun it off? I'll need to remove it, then reinstall to fix corrosion.

Thanks
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IMG_5338.jpg
- Reece
1956 Cessna 170b
Nanaimo, BC Canada
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n2582d
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Re: How To Fix Corrosion on Landing Gear?

Post by n2582d »

Reece,
I think you need to get your A&P involved in this repair. I see a couple of issues:

1.) Brake line bracket.
It appears you have a homemade bracket. I would try using a hammer and putty knife to remove the old bracket. Notice the dimple in the gear just above this bracket. That dimple is there to capture a corresponding dimple in the correct clip, p/n 0741000-7 as described in this thread. The problem with using the correct bracket is that the brake line is too short and the B-nut now lies directly behind the dimple rather than further down the gear leg. With the right equipment it's not difficult to fabricate a new line but it's a job for an A&P.

2.) Corrosion.
I can't tell by looking at the picture how deep the corrosion is. Unfortunately, if you find the depth of the corrosion to be between 0.012" and 0.063" the gear will have to be removed and shot peened according to Cessna's Supplemental Inspection 32-13-01. I would recommend talking with Tom Anderson at The Landing Gear Works or Jim Hayton of North Sound Aviation (360) 661-3302.
Click images twice to enlarge.
Landing Gear SID, Pg. 1
Landing Gear SID, Pg. 1
Landing Gear SID, Pg. 2
Landing Gear SID, Pg. 2
Landing Gear SID, Pg. 3
Landing Gear SID, Pg. 3
Gary
reecewallace
Posts: 165
Joined: Tue Jan 05, 2021 1:34 am

Re: How To Fix Corrosion on Landing Gear?

Post by reecewallace »

n2582d wrote:Reece,
I think you need to get your A&P involved in this repair. I see a couple of issues:

1.) Brake line bracket.
It appears you have a homemade bracket. I would try using a hammer and putty knife to remove the old bracket. Notice the dimple in the gear just above this bracket. That dimple is there to capture a corresponding dimple in the correct clip, p/n 0741000-7 as described in this thread. The problem with using the correct bracket is that the brake line is too short and the B-nut now lies directly behind the dimple rather than further down the gear leg. With the right equipment it's not difficult to fabricate a new line but it's a job for an A&P.

2.) Corrosion.
I can't tell by looking at the picture how deep the corrosion is. Unfortunately, if you find the depth of the corrosion to be between 0.012" and 0.063" the gear will have to be removed and shot peened according to Cessna's Supplemental Inspection 32-13-01. I would recommend talking with Tom Anderson at The Landing Gear Works or Jim Hayton of North Sound Aviation (360) 661-3302.
Click images twice to enlarge.
HP0001.jpg
HP0002.jpg
HP0003.jpg
Thanks for all the info.

I have 180 gear on the plane, does Cessna's Supplemental Inspection 32-13-01 still apply? The corrosion looks to be superficial to me, but I have no way of accurately measuring the depth. I'll talk with my AME (Canada) tomorrow and see what he says about repairing it....he told me to just do it myself :D

I'd like to keep and reuse my current brake line brackets as the correct Cessna clips are $$$
- Reece
1956 Cessna 170b
Nanaimo, BC Canada
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wabuchanan
Posts: 147
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Re: How To Fix Corrosion on Landing Gear?

Post by wabuchanan »

Reece,
Can't help with the corrosion issue, but this thread has alternative brake line brackets and materials discussed.

viewtopic.php?f=24&t=15730
1950 170A N5776C SN:19730
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Kevin Pearce
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Re: How To Fix Corrosion on Landing Gear?

Post by Kevin Pearce »

Reece

You can follow the SID sheets above, particularly page 3. Remove the paint around the corrosion and follow the instructions. If the corrosion is within limits feather the paint around the area gradually using finer wet and dry to around 400 grit. Then I would feather out any damaged paint areas and 400 all over. At this point I personally use a anti rust product to kill corrosion that may exist (Must for Rust). I did not want to use my sprayer so used a 6” roller to apply the primer, with 400 wet and dry rub down as required. If you go through or feel it needs it apply another coat. Light rub with 400 or 600. Clean and mask nearby fuselage and strut etc. I decided to try aerosol (rattle can) epoxy paint as I had read that several restorers often use this for smaller jobs. Shake the can really well, try on some board first then spray the edges and flat sided. Fairly fast moving light coats lengthways and across. Be patient and apply coats until you have a even colour following the can instructions. Mine came out very well and should be fine until the next airframe re-paint.
reecewallace
Posts: 165
Joined: Tue Jan 05, 2021 1:34 am

Re: How To Fix Corrosion on Landing Gear?

Post by reecewallace »

Kevin Pearce wrote:Reece

You can follow the SID sheets above, particularly page 3. Remove the paint around the corrosion and follow the instructions. If the corrosion is within limits feather the paint around the area gradually using finer wet and dry to around 400 grit. Then I would feather out any damaged paint areas and 400 all over. At this point I personally use a anti rust product to kill corrosion that may exist (Must for Rust). I did not want to use my sprayer so used a 6” roller to apply the primer, with 400 wet and dry rub down as required. If you go through or feel it needs it apply another coat. Light rub with 400 or 600. Clean and mask nearby fuselage and strut etc. I decided to try aerosol (rattle can) epoxy paint as I had read that several restorers often use this for smaller jobs. Shake the can really well, try on some board first then spray the edges and flat sided. Fairly fast moving light coats lengthways and across. Be patient and apply coats until you have a even colour following the can instructions. Mine came out very well and should be fine until the next airframe re-paint.
Thanks for this. I read the SID, and between that and your instructions I should be able to figure it out.

Does your epoxy paint have a primer in it?
- Reece
1956 Cessna 170b
Nanaimo, BC Canada
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c170b53
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Re: How To Fix Corrosion on Landing Gear?

Post by c170b53 »

Probably more going on than meets the eye. Why comes to mind, when the original design simple clip does the job. Looks like one bad idea, led to another rather than just fixing a simple brake line. At this point anything done is better than nothing but be careful, mistreating high strength steel is easy and can be expensive.
Jim McIntosh..
1953 C170B S/N 25656
02 K1200RS
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Kevin Pearce
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Re: How To Fix Corrosion on Landing Gear?

Post by Kevin Pearce »

I used a good two part auto primer with a roller, followed by a light rub down.
You could use a white epoxy primer from Aircraft Spruce, either spray or roller. Followed by top coats of your choice.
I wanted to try this simple method and found that it worked very well. It is ideal when you don't want to set up your compressor and clean paint guns for a small job.
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