I have a 7GCBC that has not had the bent steel u bolt replaced. Looking at options, I see the bar and bolt offering from Aircraft Spruce and ACA. I also have seen a machined bar and bolts from Able Air that has STC for my model. Is there any best option? The Able Air appears less expensive and complete with all hardware.
1973 7GCBC landing gear U bolt replacement
- Thread starter TX73GCBC
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Ron86654
www.advancedtailwheeltraining.com
I like to support ACA unless there is a significant difference in cost.
You should also change out the inner bolt.
You should also change out the inner bolt.
Bob Turner
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Ron is correct - look for MS bolts on the U bolt replacement, and get them on the inner connection as well. Very expensive bolts.
When I did it, ACA wanted $128 each for the bolts - I got them from Genuine for something like $28. Be sure to use the correct washers under the heads - that is critical, unless the bar has the proper radius.
Pay attention to how you torque them. I think it is with the weight off the gear.
When I did it, ACA wanted $128 each for the bolts - I got them from Genuine for something like $28. Be sure to use the correct washers under the heads - that is critical, unless the bar has the proper radius.
Pay attention to how you torque them. I think it is with the weight off the gear.
Bob Turner
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Those look like AN bolts. I would go for a setup with MS bolts. From memory, the strength is almost double.
The MS bolts have sort of rounded heads, and are driven by an internal hex socket. (They call them "Internal Wrenching.")
I will see if I can capture a picture.
My logs show MS-20007-46 for the outer bolts, MS-20007-36 for the two inner bolts, and a must-have set of six MS-20002C7 washers - all 167,000 psi strength. That was 15 years ago, and Genuine has changed hands since then, with no current website. I cannot find these particular part numbers anywhere. But do not put up with AN hardware in these critical areas - go for 167,000 psi bolts.
I use the leftovers (shorter, steel gear legs) for my tailwheels. No more sheared tailwheel bolts, I hope.
Let me try for a photo:
Military Standard MS20005-26 Steel Undrilled Head Bolt, Internal Wrenching - 5/Pack
Didn't work, but you can go there for their photo. The -7 is just bigger and longer, but looks the same in a photo.
The MS bolts have sort of rounded heads, and are driven by an internal hex socket. (They call them "Internal Wrenching.")
I will see if I can capture a picture.
My logs show MS-20007-46 for the outer bolts, MS-20007-36 for the two inner bolts, and a must-have set of six MS-20002C7 washers - all 167,000 psi strength. That was 15 years ago, and Genuine has changed hands since then, with no current website. I cannot find these particular part numbers anywhere. But do not put up with AN hardware in these critical areas - go for 167,000 psi bolts.
I use the leftovers (shorter, steel gear legs) for my tailwheels. No more sheared tailwheel bolts, I hope.
Let me try for a photo:
Military Standard MS20005-26 Steel Undrilled Head Bolt, Internal Wrenching - 5/Pack
Didn't work, but you can go there for their photo. The -7 is just bigger and longer, but looks the same in a photo.
Last edited:
funkydrum
New member
Long time listener, first time caller....
Was this an AD, OR just a known maintenance item ?
I'm looking at a '74 7GCBC and would like to address this.
Was this an AD, OR just a known maintenance item ?
I'm looking at a '74 7GCBC and would like to address this.
Bob Turner
Well-known member
- Joined
- Apr 4, 2018
- Messages
- 3,923
Just a known maintenance item. Do it before your first landing as owner. Might change the inner bolts to MS at the same time - fairly easy.