BC12-D Overhaul

[BIGK]

Hello all
I am now the proud owner of a not so shiney Taylorcraft BC12-D. Ex N96002 now G-BIGK. She is in my workshop having a good going over. The previous owner has sadly neglected her. I have a few question that I need some help with please but will only ask one today. On the undercarriage leg top attachment points there is a small hole with a self tapping screw. Is there supposed to be a grease nipple fitted here? On the Auster and Piper there is a nipple but not on the taylorcraft. Or is the screw for retaining the bush? Thanks in advance.#

Roger

[3Dreaming]

Re: BC12-D Overhaul

That screw is a cap to a oil reservoir for the bushing. You remove the screw and add oil, not grease. The oil will soak into the Oilite bushings.

[Hank Jarrett]

Re: BC12-D Overhaul

OK, learned something new here! My gear doesn't have a plug. I will have to look and see if the hole is threaded.

Hank

[3Dreaming]

Re: BC12-D Overhaul

It is typically just a #4 PK screw.

[PA1195]

Re: BC12-D Overhaul

I've looked at mine...seventy five years old and now covered with a colored powder coating. Not worth the hassle to try to remove even if they ever would. Just as effective to spray a penetrating lube to the bolt between the fuselage bracket and gear leg for now. When I remove the gear this week I'll inspect the assembly and bolts for wear and grease.

Gary

[Robert Lees]

Re: BC12-D Overhaul

...When I remove the gear this week I'll inspect the assembly and bolts for wear and grease. Gary

Firstly: Gary I'd suggest you replace the bolts (I know you'd do that anyway) because for their cost, it's a no-brainer. The original porous oilite bushes can wear, usually through crush damage because they are actually quite weak. I replaced mine with custom-made phosphor-bronze bushings, but I'm in the UK where we can do that without offending the FAA.

Secondly: Welcome to Roger from the UK , who has been in contact with me earlier this week by phone about his new purchase! Roger is an LAA Inspector like me (sort of the equivalent of an American IA, but under our own UK rules & regulations).

Rob

[PA1195]

Re: BC12-D Overhaul

Good point Rob on the hardware replacement regardless. Is there some easily determined go-no go point for the bushings? On Cub gear an unscientific wobble test of the bolt was all I ever saw done...and then what?

My bolts are longer than standard as the ski cable tabs are slid on the extended ends and held on with a nut...usually a high temp all metal locking but castle nuts and cotter keys are my preference. After a few installations and removals the bolt threads become compromised and the nut (if self locking) can turn too easily. The ski tabs rotate and wear the bolts as well.

Bushing replacement might be a challenge in finding a part. Is there just one per fitting? Will look at your Blog for pics.

Edit: Good gear bushing info here

http://vb.taylorcraft.org/showthread.php?10197-Landing-Gear-Bushing-Size-Needed-or-Source

http://vb.taylorcraft.org/showthread.php?6874-landing-gear-bushing

Gary

[Hank Jarrett]

Re: BC12-D Overhaul

Just for "grins and giggles" can you take photos of whatever you find and report back here on condition? I think there are probably a LOT of us who have had gear go through the same kind of life and your findings could tell us if we need to do some more in-depth checking.

Hank

I've looked at mine...seventy five years old and now covered with a colored powder coating. Not worth the hassle to try to remove even if they ever would. Just as effective to spray a penetrating lube to the bolt between the fuselage bracket and gear leg for now. When I remove the gear this week I'll inspect the assembly and bolts for wear and grease.

Gary

[Robert Lees]

Re: BC12-D Overhaul

...Is there some easily determined go-no go point for the bushings? ...

The only time to tell is when you cut the bungees off, and you have the weight off the gear. Put new bolts in, and give the undercarriage a good shake to see if there is excess wear. If there is, with new hardware it's most likely to be the bushings. I replaced my bushings with phosphor-bronze ones 20 years ago, and I do the bungees every 5-6 years, and my bushings have been fine. That's the extent of my experience.

Rob

[PA1195]

Re: BC12-D Overhaul

N36007 has had nearly 3000 hrs and 33 owners. If the gear came with the fuselage it may have the original bushings, or their remains. Nothing in the airframe logs indicates otherwise. The oiling screws may have been used before the enlightened age of spray oil but no way of telling. Their slotted heads look undamaged.

I'll try to have my mechanic do the wobble test suggested with the old and some new hardware if there's time before the floats go on.

I wonder how much "meat" there is in the upper gear assembly? As in reaming to get a fit for press-in bushing stock.

Grinding a taper to the same size bolt end desired and using it as a punch self-centers the assembly. Same as driving a short tapered bolt-sized "bullet" ahead of the finish bolt to get everything aligned especially into soft float fittings. This process will be a bi-annual event.

Gary

[M Towsley]

Re: BC12-D Overhaul

Just lift the front of the plane off the ground and give the gear a shake. You can tell if one is loose.

[BIGK]

Re: BC12-D Overhaul

Thank you all for the responses and thanks for the help earlier this week Rob. I have not checked the bushes yet but will arrange to have some made. (unless you have some for sale Rob) I have just got the struts back from NDT so may get them fitted this week and then check the bushes.

Roger

[Robert Lees]

Re: BC12-D Overhaul

Sorry, Roger, I have none available; all likelihood is that they are fine. But please replace the bolts whilst you are there.

Regards,
Rob

[Mark Julicher]

Re: BC12-D Overhaul

Roger,
Welcome to the tribe, and please post photos as you progress.
It is good fun for the rest of us trying to get motivated to move our projects along

[BIGK]

Re: BC12-D Overhaul

Sorry, Roger, I have none available; all likelihood is that they are fine. But please replace the bolts whilst you are there.

Regards,
Rob

Thanks Rob
I have the bolts ready to go.

Roger