Tailspring Bushing 0442114

[tonycondon]

i have the cessna drawing for this part.

The title of the Drawing is: BUSHING - TAILWHEEL ATTACHMENT RUBBER

On the face of the drawing: NOTE: MATERIAL - #50 DUROMETER NATURAL-RUBBER OR NEOPRENE TYPE FR

[6643]

Well, I guess that settles that! Thanks, Tony!

[5836]

Dear 140 Colleagues,

I've enjoyed the ongoing discussion about R&R of the Tail-spring Bushing. There have been several valid points made. In the end it looks like we have come "full circle" back to my original question dated February, 2nd (Rubber or Steel/bronze)?

I have completed my other maintenance squawks and will address the tail-spring. If Cessna Engineering does not clarify the part number, I'll plan to install a new version of whatever come off.

Clear Skies,
Mike 5836

[wingspinner]

i have the cessna drawing for this part.

The title of the Drawing is: BUSHING - TAILWHEEL ATTACHMENT RUBBER

On the face of the drawing: NOTE: MATERIAL - #50 DUROMETER NATURAL-RUBBER OR NEOPRENE TYPE FR

Glad you are happy about that John but it actually only answers the ancillary question as to what material part 0442114 is made of. Knowing that 0442114 is rubber helps however the reason I asked that question in the first place is because some 140s have the later steel part from the factory(at least two 1948s at this field according to their owners and others according to Neal Wright) but all the parts books seem to show only 0452114 rubber part. Is this because 0442114 was superseded by the steel ( and a larger diameter bolt) and the documentation has been lost ( such as a service bulletin)? Or, is it because that’s what they had on hand since Cessna was gearing up to build the 140a at the time?

Don’t yet know the answers but there must be a reason Cessna made the change and it should be documented somewhere.

[6643]

The steel bushing and larger bolt appear in the 140A parts catalog. The 140A predates the 1959 version of the 140 parts catalog, which was not updated with the 140A parts. There is no service bulletin calling out a production change*, or a recommendation to upgrade to the 140A parts. There is no AD requiring the parts to be updated. In short, there appears to be no documentation to support use of the 140A parts in the 120/140.

*SLN-17 is an example of a production change documented by service letter. This change was also mandated for earlier planes by AD.

It is clear in today's regs that any modification to the landing gear constitutes a major modification, and must be supported by approved data, and documented on a Form 337. It wouldn't surprise me to find ancient instances of 140A parts used to "upgrade" the 140 tail spring assembly, especially if there was even the hint of a common failure with the 5/16" bolt. It also wouldn't surprise me to see them documented by logbook entry, if at all.

It is also entirely possible that Cessna "mixed and matched" parts, especially near the end of the production run. A few years back one of our esteemed members discovered that a very early 150 actually had gear boxes for conventional gear from a 140A. I'm guessing they didn't show up in the 150 parts catalog. I don't know if there was a production overlap between the 140 and the 140A, but if there was that may account for some of the parts crossover.

I doubt we'll ever know for sure. I'm guessing there's no one left that was involved back then. All we have is the parts catalog and the drawing, and they both say the bushing is rubber and the bolt is an AN5.

I don't think we've come up with a steel bushing that would fit a 5/16 bolt, but if there was one, that might be one of the reasons the 5/16 bolt was deemed inadequate, as it would transfer the bending force of the spring to a shear force on the bolt. The rubber bushing would almost completely eliminate that.

My take on all this: If you have a 5/16" bolt and a rubber bushing, do nothing, or replace the bolt prophylactically. If you have a 5/16 inch bolt with a steel bushing, replace the bushing with rubber and use a new bolt. If you have a 3/8" bolt and a steel bushing, well, I'd be tempted to think "as far as I know it's always been like that"...

Bottom line, though, is it's up to the IA signing off your annual inspection.

some 140s have the later steel part from the factory(at least two 1948s at this field according to their owners and others according to Neal Wright)

The impression I got from Neal was not necessarily that they came from the factory that way, just that some of the ones he surveyed were like that.

[Edit] There is a notation on the drawing that leads me to believe that it also applies to the early Cessna 170s, too.

[edidin]

FWIW - I just replaced all the springs in my C120. Upon removal of the old ones I was shocked to find a degraded bit of what seemed to be rubber around the main tail spring bolt.

Called Cessna piston support who as usual were excellent. They read off the dimensions of the bushing after I asked (figured I was going to be turning a new one) and then informed me it was in fact rubber. Can’t remember which size hose it is made from at the moment, but that’s what goes in there.

Used the Univair set and all was well with the new springs, hardware, and a new tailwheel for good measure.

Neal Wright does point out that the orientation of the flat lipped plate that goes over the main spring under the washer and nut is oriented incorrectly in the parts manual.

EDIT - realize that some of this post is redundant, my browser did not show me the second page in thread initially.

[6597]

As we are grindng away on the subject, here's what I had moons ago. A metal bushing that was deteriorating, a homemade (by me) metal bushing, and the final radiator hose piece, which works super. In the background I'm gluing up a 0442124 Assembly Strip-Tailwheel Spring Abrasion. I did have the incorrect double-bend set on my early SN 140, may be why there was a metal bushing in there, who knows.

[wingspinner]

The steel bushing and larger bolt appear in the 140A parts catalog. The 140A predates the 1959 version of the 140 parts catalog, which was not updated with the 140A parts. There is no service bulletin calling out a production change*, or a recommendation to upgrade to the 140A parts. There is no AD requiring the parts to be updated. In short, there appears to be no documentation to support use of the 140A parts in the 120/140.
.
.(Removed text for brevity)
.
My take on all this: If you have a 5/16" bolt and a rubber bushing, do nothing, or replace the bolt prophylactically. If you have a 5/16 inch bolt with a steel bushing, replace the bushing with rubber and use a new bolt. If you have a 3/8" bolt and a steel bushing, well, I'd be tempted to think "as far as I know it's always been like that"...

Bottom line, though, is it's up to the IA signing off your annual inspection.

"some 140s have the later steel part from the factory(at least two 1948s at this field according to their owners and others according to Neal Wright)'
The impression I got from Neal was not necessarily that they came from the factory that way, just that some of the ones he surveyed were like that.

[Response from Ron: I'm aware of that however two owners whose family purchased their 140's new claim theirs did come from the factory that way]


[Edit] There is a notation on the drawing that leads me to believe that it also applies to the early Cessna 170s, too.

Just to put this thread to some form of rest, I'm mostly in agreement with John C.'s post (partially quoted above). The data I've been able to gather is:

- It seems, based on available data, that Part number 044114 as listed in all parts manual revisions I can find for the 120/140 most certainly refers to a rubber "bushing".
- I have confirmed both from Cessna/Textron and Univair that the same part location on the 140A/170A is is made of steel and still available and is listed as part number 0442129-1 for the 140A and 170A in their respective parts manuals.
- In discussions with an A&P and an IA here are KLVK (the IA is the son of the IA that he says worked with Neil Wright and according to him when Neil writes "We" his father is who Neil was referring to - apparently Neil was neither an IA or A&P). These to sources say they've seen a number of 140's with the steel bushing and they say their own 140's came with the steel bushings along with the AN6 bolt from the factory as opposed to the rubber bushing and AN5 bolt shown in the 120/140 parts book.

So, my conclusions are:

- If one has the rubber bushing with an AN5 bolt in his/her's 120/140 and it's working for you then you seem to be justified in continuing down that path.
- If one has the steel bushing with an AN6 bolt installed in a 120/140 there is some justification for continuing down that path because there is no way to prove it didn't come that way from the factory (unless it's a 140A).
- And, as John C. writes, if one wishes to change to the steel bushing with an AN6 bolt and your IA will approve it then you are good to go as well.
- There is good clarification (to me anyway) on the question of 044114 being steel or rubber - It's some sort of reinforced neoprene apparently
- There remains a lack of documentation on how some 140's ended up with the 0442129-1 steel bushing and an AN6 bolt since there appears to be no service bulletin or parts books that show it.

Anyhow, I've spent as more time on this than I expected to and it's time to move on and get the airplane back together. I do believe however, that it would be useful to the group if the person who mentioned they have the Cessna drawing for the 044114 part would publish it to the group for documentation backup for owner fabricated rubber bushings.

Thanks to all who provided info and participated in the discussion!

[6643]

it would be useful to the group if the person who mentioned they have the Cessna drawing for the 044114 part would publish it to the group

I would do that, but the drawing remains the property of Cessna and so we would need their permission to publish it.

One thing I would stress is there is no justification for an AN5 bold with a steel bushing, and I can see how that could put a shearing stress on the bolt which could lead to failure, so would definitely exclude that configuration from the list of acceptable ones.

[wingspinner]

it would be useful to the group if the person who mentioned they have the Cessna drawing for the 044114 part would publish it to the group

I would do that, but the drawing remains the property of Cessna and so we would need their permission to publish it.

One thing I would stress is there is no justification for an AN5 bold with a steel bushing, and I can see how that could put a shearing stress on the bolt which could lead to failure, so would definitely exclude that configuration from the list of acceptable ones.

With regards to the drawing seems doubtful it falls in the category of corp secret especially for a 74 year old part they no longer make or sell. But given you have a copy I guess if some needs/wants it they can get a copy from Cessna themselves.

With regards to your statements about the AN5 bolt with a steel bushing, I never suggested that however at the same time I’m not sure I agree with your assessment since it’s not clear why there would be more shear stress on the bolt since it’s only supported at one end anyhow. The only thing for sure against that configuration is it isn’t shown in the parts books everyone seems to have and it would constitute a design change without supporting data in that case.

Anyhow, moving along….