Outboard landing gear bracket

[hilltop170]

Most guys I know that remove and reinstall the main gear legs fabricate a wedge seating tool out of a piece of a 3/16" x 2" flat bar stock and cut a notch in the center of the punch so that it straddles and clears the bolt and contacts both sides of the wedge equally, helping the wedge to go in perfectly straight. If using a single punch, the wedge can get cocked unevenly creating point loads instead of line contact between the wedge and gear fitting.

I would think P-Ponk would make their gear fitting openings big enough for the thickest gear that could be used, such as 185 gear. So, the #6 shims might need to be used. The #6 shims are optional and used only if needed.

[n2582d]

I believe the shims are used just to snug the gear into the bracket not for alignment. ...

I've been of this opinion as well. However, I see that Cessna refers to the wedge shims (p/n 0741007) as "Shim - Spring Alignment". How do you all position the gear - fore and aft - prior to installing the wedges? My thinking would be to position the gear as far aft as possible as that is where braking would tend to take the gear if the wedge shims were loose.

I have been unable to find p/n 0741007 as called for in the C-170 IPC but there are two different shims used on the C-180. P/N 0741022-1 is a .036" steel shim and p/n 0741022-2 is a .050" steel shim. These wedge shims are outrageously priced from Cessna; $101 and $84 respectively. Altee Dodge has them (and a tapered shim) available for more a reasonable price. Dodge's shims are also sold through places like McFarlane and Univair.

The other shim (p/n 0541105) is placed on the inboard gear attach bolt. Cessna refers to this as "Shim - Adjustment". In the Service Manual it calls for using up to three of these adjustment shims to bring the wingtip height to within three inches of each other. These shims are $108 each from Cessna. Anybody know how thick they are?

[DWood]

Gary:
I bought shims a few years ago from Univair.
Dan

[n2582d]

Dan,
Did you buy the inboard shims (p/n 0541105) or the outboard wedge shims? Doesn't look like they offer the inboard shims now and one would save at least $214 (depending on shipping costs) buying 4 of the .050" outboard shims from Atlee Dodge vs. Univair.

[lowNslow]

I believe the shims are used just to snug the gear into the bracket not for alignment. ...

I've been of this opinion as well. However, I see that Cessna refers to the wedge shims (p/n 0741007) as "Shim - Spring Alignment". How do you all position the gear - fore and aft - prior to installing the wedges? My thinking would be to position the gear as far aft as possible as that is where braking would tend to take the gear if the wedge shims were loose.

I guess you could consider them for "alignment" of sorts but basically it's just to secure the wedges firmly in the bracket, and yes, Pponk does say to install the gear full aft. As Richard mentions, the 0741007 (#6) is listed as "AR" (as required) and you may need any number of these. There only function is to keep from bottoming out the wedge before getting the gear snug.

As far as the inboard shims you could probably make your own or use the C180 shims, the service manual even mentions that some models just using AN960 washers.

[DWood]

Did you buy the inboard shims (p/n 0541105) or the outboard wedge shims?

Outboard, I considered making them but at the time they were very cheap. They went on top of the wedges and still work very well to tighten the legs.

[n2582d]

... Pponk does say to install the gear full aft.

If all else fails, read the directions! Thanks, I missed that. Another great step-by-step tutorial on gear alignment is given by Lopez here.

Someplace I read that MAF, on their C-185's, used a longer bolt with a compression spring between the bolt head and the wedge to maintain some pressure on these wedges. Probably something to consider only if routinely landing on extremely rough airstrips.

[hilltop170]

The inboard shims that go on the landing gear attach bolt inboard of the outboard gear fittings is really nothing more than a flat washer and should only be used to raise a wingtip to level the plane. Obviously the wingtip measurements have to be made on a flat floor.

Although you would never use the inboard shims for gear alignment, when you add one or more inboard shims, the addition of shims will change the gear alignment at the wheel. So alignment should be checked after the inboard shims are added. In most cases it probably won't affect alignment much.

If you are adding the P-Ponk gear reinforcement blocks, you need to level the wings and add any inboard shims BEFORE the P-Ponk kit is installed, otherwise the gear will not fit if you need inboard shim(s). If the P-ponk kit has already been installed and you need to add inboard shims, the P-Ponk block would have to be removed and milled to fit the added inboard shims.

[bagarre]

The inboard shims that go on the landing gear attach bolt inboard of the outboard gear fittings is really nothing more than a flat washer and should only be used to raise a wingtip to level the plane. Obviously the wingtip measurements have to be made on a flat floor.

Could you do the same thing with a level across the roof along the forward carry thru spar?
It would reason that if that was level, your wings should be level too. unless your plane is pretty tweaked.

[c170b53]

Interesting concept but the length of the wing I would think,would magnify the difference. I guess you could be very careful in your measurements but really precision is a state of mind, hence the use of shims.

[hilltop170]

The inboard shims that go on the landing gear attach bolt inboard of the outboard gear fittings is really nothing more than a flat washer and should only be used to raise a wingtip to level the plane. Obviously the wingtip measurements have to be made on a flat floor.

Could you do the same thing with a level across the roof along the forward carry thru spar?
It would reason that if that was level, your wings should be level too. unless your plane is pretty tweaked.

If you really want to be correct, first you would make sure the wings are rigged correctly and the plane flies straight, then check for wing tip height above a flat floor, then shim the gear to get both wing tips the same height, then align the main gear.

[ChMusser]

Can anyone help identify the difference between p/n 0713495-3 & 073495-4 (outboard bracket, landing gear support). I know the numbers have been up dated, but just looking at them, how to tell which is which? they look the same to me. ... Unless they aren't correct. I just acquired two, and they seem symmetrical? Can one go to either side?
Thanks, Chuck

[GAHorn]

Can anyone help identify the difference between p/n 0713495-3 & 073495-4 (outboard bracket, landing gear support). I know the numbers have been up dated, but just looking at them, how to tell which is which? they look the same to me. ... Unless they aren't correct. I just acquired two, and they seem symmetrical? Can one go to either side?
Thanks, Chuck

Chuck when you have identical PNs except for the “dash”... usually, the ODD dash-number is the left side and the EVEN is the right side parts.

[n2582d]

I just went to the shop to look at mine. It's not readily apparent to me what the difference is between the left and right extrusion. I was going to say that they have different numbers because the nutplates are mounted on the inboard side of each and therefore the parts would not be interchangeable. This would explain why p/n 0713495-19, the left outboard bracket assembly, has a different part number than 0713495-20, the right outboard bracket assembly, but not why the individual part you're asking about is different. I thought maybe the gear leg slot was milled at some angle other than 90º to the face but it appeared to be 90º on mine. For the definitive answer I'd call Steve at Pponk.

Pponk outboard bracket

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