Outboard landing gear bracket

[N8293A]

Dave
They used an engine hoist and cable attached to the engine mount near the firewall. Then added a high wing jackstand at the tie down ring to stabilize the whole airframe. I'll try to get a photo tomorrow.

[48RagwingPilot]

You're adding years to a classic!!

[DaveF]

You're adding years to a classic!!

Steve's airplane is beautiful. He had to dig pretty deep to find something that needed replacement.

[N8293A]

Dave
Thanks for the compliment. I've owned the airplane for 15 years, put 1100 hours on it and this is my first "major" repair. Which is a tribute to the gentleman in Fairbanks who did the restoration. The guys at the shop are doing a great job and I hope it returns to service better than before.

[johneeb]

Dave,
Inboard side, and during the annual the mechanic used an inspection camera just to take a peak inside the gear box area. The first picture in the post shows the crack that caught his attention. This was reason enough to pull the gear leg and have a more detailed look. At that point we saw the bulge caused by the corrosion, and also caused the crack.

John,
We are only doing one side. The inspection of the right side showed no anomalies. Their is a picture of the new part in the photobucket link. The new part is beefier, and rather than a stamped or extruded part, this part is milled from a solid block of aluminum.

Sorry I missed the pictures that were not on the first page of photobucket.

[N8293A]

Dave,
Here's a link to photos of the engine lift and jack stand.
http://s328.photobucket.com/user/smcgre ... %20Uploads

[johneeb]

Steve,
Thanks again for posting your pictures. Because of your posts, today (doing annual) I boro-scoped both sides of my gear box and fortunately found everything in good condition. In the past I have relied on visual inspection with a mirror.

[N8293A]

John,
That is the beauty of the forums, it keeps everyone thinking. This repair wasn't necessitated by normal wear and tear. I think Jim hit the nail on the head with this one. Just a small amount of movement of the gear leg on that bracket set up a grinding motion that forced iron oxide into the aluminum. This set up the process of dis-similar metals corrosion. Granted it took over sixty years to finally crack that bracket. I will certainly be keeping an eye on the right side now. With the advent of inexpensive (Harbor Freight) inspection cameras, there is no reason not to look over every square inch of our aircraft.
By the way, you need to stop by C77 and visit us some time, the welcome mat is always out.

[johneeb]

Thanks for the invitation Steve. Did your gear have the shims (number 6 in the below drawing) installed? If not that may have contributed to the gear movement.

[c170b53]

Whack-a-mole Steve, eventually with enough tries I might hit one.

[jlwild]

[quote="johneeb"]Thanks for the invitation Steve. Did your gear have the shims (number 6 in the below drawing) installed? If not that may have contributed to the gear movement.

John, your question caught my attention. I have watched my gear come off and on twice and don't remember seeing the small #6 shims being present on my 170B. Do any of our members know If these shims used for alignment purposes?

[johneeb]

Thanks for the invitation Steve. Did your gear have the shims (number 6 in the below drawing) installed? If not that may have contributed to the gear movement.

John, your question caught my attention. I have watched my gear come off and on twice and don't remember seeing the small #6 shims being present on my 170B. Do any of our members know If these shims used for alignment purposes?

Jim,
That is the way I have used them, I have one under the gear leg on the left gear and one top on the right gear. I did that to try to level the wings while the aircraft is sitting on the ground empty, it helped.

[sfarringer]

When I installed new outboard brackets (from pPonk) a few years ago, the new brackets had a taller gear opening than the original brackets.
Extra shims were required to fill the space.
At the time, I also changed from the original gear (with step holes thru the center of the gear leg) to the later "lady leg" gear. But either gear would have needed the "extra" shims.

[N8293A]

John,
When we disassembled the gear, there were no shims installed. The wedges were tight against the gear leg, and the bolt wasn't bottomed out. So the thinking was there was no need for the shims. Now when we install the gear legs with the new bracket the fit may require the shims, we shall see. The other factor here is I do have the 180 gear legs, so that may have a small impact on fit. Prior to the repair, and over the past 15 years I have never had an issue with how the aircraft tracked on the ground, so again the thinking is there was no need for the shims. Now, with the changes to the left side, I am a little concerned about my first flight. I don't know if there is going to be a change in tracking because of the repair. We shall see.

[lowNslow]

I believe the shims are used just to snug the gear into the bracket not for alignment. If you have a wing low the procedure (per C100 series service manual) is to install a washer or shim under the gear on the main gear attach bolt on the low wing side. Here are the gear install instructions from Pponk:

Steps to Installation

1) Hoist the airplane.

2) Install your gear in the aft position. This should leave you 1/16th to 3/32nds inch gap between the gear and the front of the bracket. If the gap is larger than this, check the rear portion of the bracket that touches the landing gear to see if it has compression damage due to years of use and striking objects with the landing gear. (Inspect for stress fractures and cracks in any compressed areas.) A symptom of "too large a gap" is a chronic "clunk" when you land or take off. Tightening the shims is only a temporary fix for the problem...the "clunk" usually comes back.

3) Install the wedges and shims so that they do not push all the way in and bottom out. If they bottom out, install an extra shim. (Parts Manual allows more than one shim. You also may need a thicker wedge.) There are 2 sets of shims and wedges holding each set of gear in place.

4) Tap the forward wedge lightly with an aluminum punch and hammer to set the wedge. Screw your 1/4" bolt up snug to the wedge.

5) Repeat this procedure for the rear wedge.

6) Tap the forward wedge again lightly with a punch and hammer to reset the wedge, and again snug up the 1/4" bolt.

7) Repeat this procedure for the rear wedge.

Note: Do not over tighten this bolt...it is there only to keep the wedge from backing out. DO NOT POUND IN THESE WEDGES, THINKING YOU WILL KEEP THE GEAR FROM MOVING. You only will damage the outboard brackets (and keep me in business).