Wing strut attach bolt bushing

[Longwinglover]

Hey group (especially you professional maintenance types)!

I've got a couple of friends who have a 1941 J3. We have discovered that the bushing for the left front wing strut is loose in its' hole in the rear landing gear / lift strut attach fitting (the hole in the fitting is worn).

The airplane was completely rebilt 7 years ago. The bushings were looked at, but NOT replaced at the time of the rebuild :x .

When they originally found this problem about two weeks ago, they thought that the movement was due to the bushing being worn, allowing movement of the bolt. They ordered a new bushing and bolt from Univair, but after tapping out the original bushing, found that the new one easily slipped into the hole with only finger pressure (it should be a press fit). When they temporarily re-attached the strut, the original movement was still evident. That was when we determined that the real problem was that the hole that the bushing was in was slightly worn/elongated. (Don't ask how or when - nobody knows. )

The logical fix is to ream the hole round (removing as little material as possible) and to manufacture a new bushing to press into the now slightly oversized hole.

The problem is that the resident (yes, he actually lives at the airport) FAA maintenance inspector has adamently said that can't be done without approved data. (Don't ask how he got wind of the problem. )

My request of you guys is: Does anyone have approved data for such a fix? I am making a request to Piper (through the local dealer who doesn't know anything about J3's) but am not holding my breath. Since the J3, J5, PA-11,12,15,17,18,20 and 22 all had a similar wing strug attach arrangement, does anyone know if Piper previously published any guidelines for fixing this problem? Has anyone done a similar fix and do you have a copy of a 337?

Answers from this group will certainly be faster than from Piper.

Thanks in advance for your help.

John Scott

 

[Steve Pierce]

Had a discussion with Clyde about this recently as it came up close by. Don't know of any approved data but it has been done a lot. Have you checked with Steve and Joel at the Cub Club?

 

[Longwinglover]

Steve,

Thanks for the reply.

I too have had conversations with Clyde and Joel. Both had good suggestions, but we're really backed into a corner needing hard approved data. My suggestion for reaming round and manufacturing a bushing jibes up with Clydes thoughts - but I'm not a DER or even a liscensed mechanic and I did NOT stay at a Holiday Inn Express last night! 8)

With so many similar fittings in use on similar fabric Pipers, I thought Clyde would surely know of something! By posting here I am hoping aginst hope someone has something - SB, 337, SOMETHING.

John Scott

 

[Steve Pierce]

It has been done as you describe.

 

[N5126H]

I just did that on my cub. Drilled out the hole, welded in a new piece of 4130 pipe with the correct ID and ground it down to fit. Worked great. Log book entry only required. It is better to ask for forgivness than it is to get permission.
Bill

 

[T.J.]

delete

 

[bob turner]

I agree with the last several posts - this is a minor repair, and a logbook entry should suffice. It is hard to believe the feds even know the ferrule exists, let alone that yours is loose. Are they mad at you? The oversize bushing is the safest way to go - no heat involved - but I am sure that you could add material in the hole, then drill and ream for the stock bushing, and still be in the minor repair category for log entry.

Here's a thought: the oversize bushing is probably going to be within .005 of the stock bushing, so just tell the fed that it is a stock bushing carefully selected from the bin, and the factory tolerance is at least that much?

 

[Steve Pierce]

I figure Univair was off on the tolerance and you can come up with the correct one.

 

[bob turner]

Just got this month's AMT - a free magazine for mechanics. Bill O'Brien, the FAA guru on all things maintenance, and Joe Hertzler, among others, have interesting articles printed therein.

I am not at all sure I understand completely everything that these two knowledgable individuals said, but it seems like (1) there will be no more major modifications approved by 337 - only by STC. In special cases, a one-time STC will be granted - by engineering, not FSDO inspectors. Next, some sort of legal change is slated for 43-13, allowing the contents, under certain conditions, to be used as approved data (as opposed to acceptable data, which may no longer be good authority?)

As stated, I am not sure of this stuff - I was just getting the hang of being a moderately conscientious IA - maybe this should be a new topic?

Let's have an update on your lift strut bushing - did more reasonable heads prevail, or do you have to buy a PMA fuselage?