The International Cessna^® 170 Association

cessna170bdriver wrote:

edbooth wrote:

Aryana wrote:I'm always on the lookout for item #2 as a standalone piece since you can't buy the pressed bolt separately. Doesn't come up very often by itself.

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About 25 years ago someone offered to sell me a completed new tailwheel assembly for 200 bucks... I didn't take it. Talk about a dumb a$$.

Not as dumb as not buying every single set of wheel pants Tom Hull talked Cessna into making in the late 80's for $1200/set...

Given 2.7% inflation and a start date of 1985, $1,200 back then would equate to near $2,700 today.
If that still sounds like a bargain, I have a REALLY nice set of wheel pants to sell you at the 1985 dollar value of $1,200.

Bruce Fenstermacher wrote:Ok Ed, I see where you abused that bracket by dragging it on the asphalt all over tarnation. Maybe, just maybe you finished that part off.

Bruce, Here is a little better picture. You can see it's mostly trashed.

Ed, that damage will buff right out!

It's calling your name

bagarre wrote:

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It's calling your name

Tempting Dave, but I really want a new bracket assembly (this has the critical bolt) and the heavy duty Arm assembly.

I put the heavy duty steering arm on mine, still steers like crap

But unknown hours on the king pin is a valid concern. I think yours is the third in 4 years that I've heard of breaking.
Have you inspected the break point? Was there an existing or migrating fracture or was it 100% at once?
Pretty wild that yours fell off on takeoff. That sounds like it might have broken a while ago.

It reminds me of when the rudder broke off on my sailboat. The shaft was failing over time with no indications (the crack was slowly migrating) and one day, on a very calm sail, it just fell off.

I wonder if an NDT of the pin would reveal one ready to fail.

bagarre wrote:I put the heavy duty steering arm on mine, still steers like crap

But unknown hours on the king pin is a valid concern. I think yours is the third in 4 years that I've heard of breaking.
Have you inspected the break point? Was there an existing or migrating fracture or was it 100% at once?
Pretty wild that yours fell off on takeoff. That sounds like it might have broken a while ago.

It reminds me of when the rudder broke off on my sailboat. The shaft was failing over time with no indications (the crack was slowly migrating) and one day, on a very calm sail, it just fell off.

I wonder if an NDT of the pin would reveal one ready to fail.

The bolt is messed up pretty bad, since it broke right where the grease hole was, I'm thinking if an NDT had Been performed it might have revealed a crack starting there. I guess it held up pretty well with 62 years of landings....some of them really challenging to that whole assembly. I have watched these things up close and personal judging spot landing contests.....wow, it's scary.

We have a life limit on the main spring but I've heard of more king pins breaking than main springs.
Should these be sent in as SDRs? The 170's can't be the only Scott 3200 equipped plane to be experiencing this.

If I get bored enough, I might put some dye on the one I have in the garage. Kind of a shame, I JUST took it apart and re-greased everything.
But it's not much trouble to get one apart on the bench.

Aryana wrote:

bagarre wrote:Should these be sent in as SDRs?

IMO, no.

To avoid the possibility of an AD or because an SDR is the wrong vehicle to convey the failure to the FAA?

Aryana wrote:IMO this isn't a serious failure, malfunction, or defect that constitutes notification to the FAA. Some of these tailwheels have thousands of hours on them, and they were never meant to last forever. What we do know is that they do have a very good track record over the past 60+ years.

Just like the main leaf spring, perhaps we should consider buying new tailwheels after say, 5000 hours/50 years...whichever comes first? Just a thought.

Yeah, what he said ! Mine has (had) approx 6000 hrs.

Correction guys.... The bolt that I thought broke at the grease hole did not break there. After further cleaning and inspection, it broke at the shoulder where it is machined down to fit the lower bearing.

Same place mine broke Ed.

Do you have an high res sectional shots of the break itself?

bagarre wrote:Do you have an high res sectional shots of the break itself?

No I don't. It really would not show anything as it evidently broke while taxiing. (About a two mile taxi) The two pieces rubbed together for quite a while and destroyed any evidence of a crack.

Anyone know whether the Alaskan Bushwheel bracket assembly with the kingpin bolt at issue here (p/n ABI 3216-00; Spruce p/n 06-00724) is a direct replacement for the Scott bracket assembly with the kingpin bolt (p/n 3216-00; Spruce p/n 06-01291)? I know that the entire Alaskan Bushwheel tailwheel assembly is a PMA direct replacement for the Scott tailwheel, but I don't know whether the individual parts are also PMA direct replacements for their Scott counterparts. From the similarity of the part numbers it would appear that they are. But I don't have any first hand knowledge/experience about it. The Alaskan Bushwheel bracket assembly is over $100 cheaper than the Scott one at Spruce.