Control Tee Bushing

[busav8or]

I've been noticing a slight bind in my elevator lately and decided to investigate today. What I found gave me a bit of a surprise, but I'm sure glad I found it! The nut on the bolt which holds the control tee in place had fallen off and the bolt had started to work its way out of the tee itself. I noticed a little more freeplay on the right side yoke than the left with the elevators full down and found that this was due to the bolt having backed out of the tee on the right side! Upon closer inspection, I noticed that the bushing (part S-18-30 in the IPC) appears to be completely missing! Anybody know where I can find one or if the part number has changed? I've searched the usual sources for S-18-30 with no luck. Also, the bearing B-610 in the IPC (part 17) appears to be gone. No telling how long the plane has been like this, but at least for the two years I've owned it! Could have been a nasty surprise down the road!

Thanks,
Joe

[GAHorn]

I have a spare "T" in my hangar, ...I'll be home Thurs. I'll try to see if any info can be derived from that look-see.

[busav8or]

Awesome! Thanks, George.

[busav8or]

Thanks, Aryana!

[Dennis]

HI Joe, Looked around and found bushings and bearings for the control tee. Started looking a Preferred Airparts. The bushing S-18-30 is under S18-30, then changed to S2614-4-2 about $140 buks, the B610 is changed to S1997-6G10 about $30 buks. the AN200KP4 is changed to MS27640-4 and you can get it at genuine aircraft hardware (don't forget to ask them for your free Hardware Reference Book). And with 4 bushings F-620, changed to F620 and changed to S1004-28A about $17 buks. Now when you take your control tee out you can replace ALL the bushings and bearings and have a brand new control tee. Good luck and let us know how it works out. Regards, Dennis

[busav8or]

Thanks, Dennis. I saw the updated part number for S18-30 also and wondered if it's the same part. $140 for a bushing seemed kind of steep! Upon further inspection, I think the bushing may still be in there, but it's not obvious with the T in place. I assumed that the bushing would extend slightly past the ends of the hole drilled in the T which would prevent the bolt from crushing the aluminum tunnel, but I can't see it. Doesn't mean it isn't there doing it's job, it's just not obvious! I tightened the nut today and noticed that the tunnel did not get crushed so I figure the bushing must be installed.

I'll post any further findings, but FWIW, it might be worth checking the nut on the through bolt every year or so to make sure it hasn't worked loose. Sure got my attention!

[GAHorn]

Glad to see you got it worked out, Joe!
The used T I have in my hangar is not airworthy...I only keep it for reference and education, etc.., so I would not have attempted to send parts from it to you.
Bushings can be manufactured from stock (available from Spruce) by the owner. Bearings are more universal than you might suspect and can usually be sourced from local bearing supply houses in large cities....also on-line. (references have been posted here previously in other threads.)

The bushing is NOT intended to prevent some heavy-handed gorilla from tightening the thru-bolt so as to crush the tubing the T is mfd from.... It is to reduce friction and prevent wear of the tube and the thru-bolt. Use a NEW nut (friction-lock or castellated w/pin) when reassembling.

CAUTION: The control "T" can corrode/rust INTERNALLY. Later Cessna's used an open-top tube to mfr the "T" and condensation has been known to corrrode them to the point of being paper-thin and fracturing in flight.

While yours is out...be certain to test/check it for internal corrosion and rust.

[busav8or]

Thanks,George. I reassembled everything today and discovered another minor problem that I had thought was the fault of the possibly missing bushing. The controls were binding slightly and I thought it was because the through bolt was too tight and slightly crushing the tunnel walls onto the T. Thanks to other posts here on the forum, I checked the "float" of the balls ( no naugas or teflons were harmed during this process ). Turns out the ball bracket was too tight and restricting the ability of the ball the move within it thereby binding the control wheel shaft! I inserted a couple of washers under the bracket and, voila, the binding disappeared. Now I have something to blame my inconsistent landings on! The elevators were binding...yeah, that's the ticket!

Thanks, again, to everybody who responded and offered to help!

Joe

[ghostflyer]

I noticed in the last reply mention about the adjustment on the tension on his balls. My Aircraft balls are worn out and I would like to replace them. I have been to Cessna but they will not help [also Spruce]. The part no. 0411224 and I need 2 of. So does anybody know where I can procure a new set.

[GAHorn]

Wag-Aero sells Teflon control bushings (balls) at reasonable prices.

[N2255D]

Had the Wag-Aero Teflon bushings in my 140 and put them in the 170 first annual, after I bought it. They work great. find them here http://store.wagaero.com/product_info.p ... ts_id=2355

[marathonrunner]

There is a service bulletin SEB-01-03 from I think 2003. You are supposed to drill a hole in the bottom of those yokes and inspect. Then you are to fog it. I use LPS-3 and have found a few that were bad enough to need replacement. Rudder pedal posts also need attention and servicing as does the flap handle bolt. I know of two that have broken on the flap handle over the years.

That SB is for 172 and 180 aircraft but I have done it on several 170's and the local FAA thinks it a good idea and all yokes like that should be included

[GAHorn]

The affected yokes are those with open ended tops which can collect moisture, rain't, etc from
leaking windshields. Generally not C170 yokes, but a good thing to think about.
A search here should provide a copy of the document as I believe I posted a copy when it came out.It's in the MX library, SEB01-3.

Here's a link to the posted info: http://www.cessna170.org/forums/viewtop ... =32&t=5835

[marathonrunner]

Part of the problem is that any weld is porous to some degree and can and does collect moisture. Anyone who has cut into vertical tubing on welded fuselages has found this. The vertical tubing on Cubs just behind the door is one area that I have seen collect moisture and lots of it. I remember drilling into one and it weeped water fro quite some time. When the tube was cut out the bottom portion was paper thin.

I really think open or closed it is probably a good SEB to complly with.