The International Cessna 170 Association

Anybody have a part number and source for the wheel bearings in the Scott 3200 tailwheel. I am going to tear it apart and I'd like to have all the parts ready to go. Thanks.

Again, your absolutely best price source for these parts will be Air Repair, Inc...662-846-0228. You won't need the part numbers; just call its parts dep't. and tell them what you need...they'll look it up for you.

From the parts manual they are Timken A4050 bearings and Timken A4138 cups, 2 each for the wheel and 1 bearing for the fork.

I'd check a local bearing house before I ordered them.

Bearing numbers are supposedly internationaly standardized. I would suggest you check NAPA (Aircraft parts division, of course) or any bearing house. They're bound to be less expensive than airplane parts suppliers.
The numbers should be on the bearings and races.

is this repair
required to have
an inspector sign it off?
iowa

It must be logged by an A&P. As owner/pilot you can clean and grease wheel bearings, but replacing them isn't considered preventive maintenance.
See FAR part 43, Appendix A, which is quoted here: http://www.cessna170.org/phpBB2/viewtop ... preventive.

Best Regards,

John

N9149A wrote:From the parts manual they are Timken A4050 bearings and Timken A4138 cups, 2 each for the wheel and 1 bearing for the fork.

I'd check a local bearing house before I ordered them.

Bruce is correct. These are standard Timken parts. Buy'em from an aviation source to get the FAA documentation, or buy 'em cheaper elsewhere without the documentation... same part either way.

Since the Cessna parts manual lists them specifically as Timken bearings what FAA paperworkd would you need Doug.?

Exactly what I was looking for guys. Thanks

When you folks buy non aircraft parts from an auto parts store, please do your A&P-IA a favor and do not mention "REPLACING the parts.

Because if you do they might just ask for the 8130-3 that comes with a new aircraft certified part. and of course he will be required to have one to return to service as airworthy.

N9149A wrote:Since the Cessna parts manual lists them specifically as Timken bearings what FAA paperworkd would you need Doug.?

I was referring to the 8130. Sorry, should have mentioned that.

Form 8130 is not req'd for Timken bearings. Their website lists the blanket FAA-PMA approvals for aircraft use of their bearings. (And the corporate pilots for Timken got their annual checkrides administered by your forums moderator and Parts/MX Advisor who was their examiner, so.... How they gonna mess with us!!!)

I was wondering about the Timken bearings as they are specifically called out in the parts manual.

Tom's message of course is not to use unapporved parts in your aircraft and if you decide to do that be smart enough not to tell anybody.

Just remember just because it looks like a duck, quacks like a duck and flys like a duck doesn't mean it's a duck in the eys of the FAA. Unless of course it has a data tag and an airworthiness certificate in this case an 8130-3.

Back in a previous life, I was the pilot for one of the US vice-presidents and was running him around the midwest on a rapid-fire speaking tour. In the middle of that tour, tire-changes were due on the nosewheels and they were mounted on a dual-bogey that involved a "live" axle running thru two large bearings within an axle housing.
I'd called ahead to the large FBO/Service-center where we were scheduled for an overnight to pre-arrange the tire changeout. I'd made them absolutely promise they would have everything/anything that could possibly be found deficient, on hand and in-stock...as I did not want a simple tire-change to be any reason to delay the next morning's departure with VIP's.
The service center promised to have a complete landing gear overhaul kit on hand.
We landed there at 6PM and had a 8AM departure scheduled for the next day. They towed the airplane into the hangar and put the night-shift on it.
About 2AM my crewmember (who was overseeing the work) called and woke me up, suggesting I might want to come back to the airport. It seems that live axle was nearly frozen within the axle-housing due to crumbling bearings*, and the shop had no replacement bearings.
When I got there, I took a shop-rag and wrapped it around the axle and tried to turn it. It felt like a ratchet. I could barely turn it.
After I listened to the shop explain they had no bearings and couldn't get any before 9AM via Fed-Ex, I chewed them out pretty thoroughly, and my engineer and I tried to figure out some way we could extricate ourselves from the embarrassment we were about to be found in when the VP showed up in about 5 hours without a serviceable airplane. It was now 3AM.
I went into the maintenance library and looked at the airplane's IPC and realized the part numbers were Timken numbers!
I got on the phone and called an all-night autoparts store and asked for those bearings by Timken part number. The parts-guy came back to the phone a few minutes later and asked, "What year Ford tractor is this?"
I told him it doesn't matter...did he have the bearings? He said yes, but after midnight the store didn't accept personal checks and would require cash or credit card and the bearings were NOT cheap! (I needed two sets for this application.)
I asked him how much I should bring and he replied, "Twelve-bucks apiece, that'd be $24 plus tax!"
I got in a taxi and went to get the bearings while the shop disassembled the axle housing.
When the shop's inspector found the pilot's supplying their own parts for such a job, he nearly went orbital, demanding that I produce serviceable tags for the parts before they'd install them.
I showed him the airplane IPC, the Timken part number, the new bearings in Timken, orange boxes, ...and his final-inspector spoke up and pointed out that genuine Timken bearings are automatically covered by FAA-PMA if called for in the IPC.
The bearings were installed, and the flight departed with a pretty tired flight crew anyway, ontime at 8AM.
(That was over twenty years ago and I refuse to do business with that outfit to this day because of the episode.)

*The axle housing had grease-zerk-fittings on it, and it was subsequently discovered that incompatible grease had been utilized the last time the axle housing had been greased. It's absolutely imperative that different greases not be mixed. When repacking your bearings, all old grease must be cleaned from bearings before applying new grease, in order to assure that incompatible greases are not intermixed. When adding grease to already-greased bearings ...(such as like on these Scott tailwheels which have a grease-fitting at the end of the axle)... be absolutely certain to use the exact same grease each time you re-grease it. Otherwise, you must disassemble the axle, bearings, wheel, etc., and completely clean the bearings and axle of the old grease, before reassembling and reserviceing with new grease.

doug8082a wrote:

N9149A wrote:From the parts manual they are Timken A4050 bearings and Timken A4138 cups, 2 each for the wheel and 1 bearing for the fork.

I'd check a local bearing house before I ordered them.

Bruce is correct. These are standard Timken parts. Buy'em from an aviation source to get the FAA documentation, or buy 'em cheaper elsewhere without the documentation... same part either way.

I’ve been of the same opinion regarding wheel bearings but now I read this from McFarlane: