Addressing Play in Aileron and Landing Gear Pivot Points

[SomethingScrewy]

I've got two questions about addressing play in joints with bearings and through bolts. The aircraft is a 1940 BC-65.

1. I have an aileron hinge attach point that exhibits some play. Presumably there is a bearing in the attach point that can be replaced? Does anybody know what size bearing this is, and is there anything unusual to know about replacing it? If there is not a bearing, what are the options to reduce the play?
2. We see a similar issue with play at the landing gear to fuselage joints - exerting up and down force at the wheel reveals some play at the pivot point. We tightened the nut to the next castle slot at the last annual, and that fixed the play, but resulted in a tighter joint that does not pivot as easily. What is the best practice for determining how tight to go on these bolts, and how much play is acceptable? What is the typical solution if there is play?

Thanks,

Lance

[3Dreaming]

The aileron bushing is 5/16"od x 1/4"id x 3/4" long. Also available from other sources, but here is a link, https://www.univair.com/taylorcraft/...leron-bushing/ .

Here is a link to the aileron hinge pin. They are not just a normal clevis pin, they have knurling under the head. https://www.univair.com/taylorcraft/...ron-hinge-pin/ .

Often times over the years the incorrect hinge pin is installed. The hinges are not properly lubricated, and the pin will turn in the bracket instead of the bushing. This wears the bracket out. Here is a link to the bracket, https://www.univair.com/taylorcraft/...hinge-fitting/ .

Hinge pins that are properly installed for the control surfaces will rotate with the control surface. If it does not rotate with the surface it is wearing parts that shouldn't be wearing out.

The upper gear bushing is a 5/16"id x 3/8"od x 1 1/4" long. The last time I did one I couldn't find any that long, so I used two that were 5/8" long. Remember to replace the bolts too.

There is also normally a bushing in the lower end of the tie strut. It is 5/16"id x 1/2"od x 1" long. I have seen some different variations here, including there just being the steel welded bushing with no bronze insert.

[SomethingScrewy]

Thank you for the precise Univair links - I should have thought to search there before asking the question.

Your insight about the landing gear bushings will also come in handy, much appreciated.

Regards,

Lance

[3Dreaming]

One more thing about the upper landing gear bushings. Where they are installed is an oil reservoir. There is a large diameter tube capped on the ends with washers, and then a smaller inner tube where the bushing is inserted. There will be a small screw on top. Remove that screw, and you will find there is a small hole drilled through the inner tube. After you install the ne bushings you will need to drill a small hole that goes through one side of the bushing. After the gear is installed fill the reservoir where the small screw was removed with oil, then replace the screw to close it back up. This provides long term lubrication to the upper landing gear bolts and bushings.

[SomethingScrewy]

I am not seeing 5/16" ID bushings (as you mentioned for the upper and lower gear) available from Aircraft Spruce. Are they typically bronze Oilite bushings such as these?

https://www.mcmaster.com/6391K154/

https://www.mcmaster.com/6391K443/

Thanks,

Lance

[3Dreaming]

Those will be fine. You will need 8 of the 3/8 OD bushings and two of the 1/2 OD bushings.

[Mark Bowden]

Lance, also check that the cabin entry step is free to rotate. It is a pin joint for the strut attach. If you cannot rotate the step the bolt/nut is installed too tight. Use some washers of different thickness to get the nut tigth and install the cotter pin in the castle nut.
Mark

[SomethingScrewy]

Mark - good tip, thanks.

All - does anyone know if it is possible to remove the upper landing gear bolts, replace the bushings, and re-install the bolts without removing and replacing the bungees? In other words, if I hoist the airplane by the engine mount until the wheels are off the ground, remove the upper landing gear bolts (one side), and rotate the gear leg down to service the bushings, can the gear leg assembly be rotated back into place to re-install the bolts, or do the bungees create enough tension to make that difficult?

I suppose once the upper landing gear bolts are removed and the gear rotated, the bungees will be slack and can be removed without cutting them? I have access to a bungee install tool, so maybe that is the best approach. I prefer to reuse the bungees if possible because we just installed them a year ago.

Thanks,

Lance

[3Dreaming]

Yes, the bushings can be replaced without removing the bungees. You will need to make a makeshift press with a bolt or piece of all thread.