Landing gear, unilateral, right, and left

[melcessna]

I recently purchased what I thought was a pair of gear after sending them to a repair station for magnafluxing. Upon receipt, the stamps on the end of the gear are 170005 and 170007. I vaguely recall this has something to do with shims, but I am foggy. The fact the numbers are both odd lead me to believe I may have purchased two left legs as usually odd is left and even is right. As we know, no two airframes are alike and the legs may need some fitting to the airframe. However the leg on the left side slide in relatively easy and the bolt fed through with just gravity. The right is requiring a little bit of a tap, however I have not pushed the issue. Secondly, the forward radius on the left is slightly wider than the aft radius. So, when putting the right gear on the two radii are reversed, hence my thought that both are left gear. My plane is a 48 and I am very intimidated with the thought of putting those gear back on because of the plug for the steps on the 120/140. I am also familiar with the 170A parts manual starting the part number to include the 170 ragwing serial numbers. My mechanic is leaning that I may have two left, but with the naked eye it is difficult to see any change in the bend of the gear up by the tongue or down by the ankle. He said back then the production may have been just to produce one part without regard to what I have discussed above. If anyone reading this can shed some light confirming my suspension or debunking it I would very much appreciate it. Thank you for your thoughts.

[n2582d]

Mike,
I'd recommend calling Jim Hayton at North Sound Aviation or Tom Anderson at The Landing Gear Works. Tom's website says, "All the gear have serial numbers. The 170 gear will have a letter followed by numbers like Z345 while the early 180 gear will have a letter number mix like 1Y345. Later years went to the 6 digit serial number like 801123 The serial numbers are on the end or the inside of the axle attach area." Those numbers don't seem to match what you're looking at. Do you have numbers/letters stamped at the other end of your gear legs?

Upon receipt, the stamps on the end of the gear are 170005 and 170007. I vaguely recall this has something to do with shims, but I am foggy.

I think what you may be thinking of is this note from the 100 Series '62 and Prior Service Manual:

Click to Enlarge

[GAHorn]

Until 170B-model, serial number 25612, all landing gear legs were interchangeable Left/Right.

Afterwards they were “handed”.... no longer interchangeable, and readily identifiable by the lack of provision for a step and also that they were “arched” and why they appear slightly “bowlegged” and have a narrowed “ankle’ just above the axle attach area.. The early interchangeable gear have a “knock-kneed” appearance and the legs do not have a narrowed ankle, but are uniformly tapered from top, down to axle.

[n2582d]

George,
I assumed that was the case as we've written that here for years. But look at the IPC's for the straight 170 and the C-170A.

C-170 IPC Click to Enlarge

C-170A IPC Click to Enlarge

Mike has pointed out some differences in measurements on the gear which show it may not be symmetrical as I assumed it was. My thinking was that the only difference between the right and left gear on these early 170's was the placement of the hole for the brake line clamp. On the IPC drawings it does not appear to be on the centerline. I don't believe that the numbers Mike has found indicate that he has two left gear. These numbers are not part numbers. I'm guessing that they indicate that originally there were five shims under the 170005 gear and seven shims under the 170007 gear. But then I thought that was strange. Assuming these came off the same airplane why not, if the goal is just to level the wings, just have no shims on one side and two on the other? My WAG is that Cessna used shimming the inboard end of the gear not only to adjust wings level but also to adjust camber. Back with the early 170's the axle shims were primarily used to adjust toe-in and toe-out, not camber.

[sfarringer]

Gary:
I think that you are looking at an assembly, not just the spring.
In the IPC's, scroll on down to Item 27-12, which is the spring (and no left or right designation).
For some reason, in the 170A IPC, they also included serial number range for 1948 straight 170.

Steve

[n2582d]

Steve,
Thanks. You're right. I got fixated on the hole for the brake line clip appearing to be off of centerline and then the assembly p/n seemed to answer my suspicion that the gear legs were not interchangeable. Why not to post at 4:30 am.

[c170b53]

Says Gary

Why, not to post at 4:30 am.

Sometimes stuff like this turns the squirrel cage into a perpetual motion machine. Sometimes you just can’t let it go or sometimes you just got to know, yet the answer is an unknown.
Crazy, is some of the stuff that half comes out of the morning fog in my noggin.
Seriously, I’m thankful for the time and efforts of the many individuals (the collective group) who are willing to spare the time to drill down for answers.

[melcessna]

Gentlemen, great big thank you. Two key suggestions have given me great confidence I have interchangeable gear legs. That is a great relief. The first was the lack of taper in the gear ankles. The second is I contacted Tom at XP Mods who I have done business with and I was told the gear leg pictures I provided they are interchangeable. The numbers on the end of the gear down by the ankles are serial numbers for future reference, nothing to do with shims. So, within 24 hours I am moving forward thanks to all of you.

[GAHorn]

And lest we forget.... the IPC has numerous errors....especially in depictions/illustrations. It is not an “approved” document for maintenance purposes. It is an “Illustrated Parts Catalog”.... a catalog for ordering parts only.