Rudder Cable Replacement

[flyboy122]

HI All,

During my last annual we decided the rudder cables on my '53 B model were a bit too crusty. I ordered some new ones from Univair (McFarland), but as I'm getting ready to change them out this week I'm starting to wonder.

I'm thinking I can disconnect them at the pedal, cut the end off, and tape a pull string to the old cable. Then tape the other end of the string to the new cable and I should be able to just pull it pretty much all the way through, being careful and double checking the pulleys along the way. Sound ok so far? (And if you not, or you know a better way, please speak up!!!)

But then we get to the fairleads in the back.... Obviously the swaged ends won't fit through. Peaking through the elevator control rod hole I can see a wire clip on the back of the fairlead, but I'm not sure I'll be able to get it off and then back on. The other side may be worse. Any ideas on this? I searched the forum and there was a reference to just removing the brackets. Easy enough but mine are riveted on. I can drill out the rivets and replace with screws, but just wanted to see if there was a better way before I went down that road.

This is a Saturday project, and by the looks of it could be an all day one!

Thanks,
DEM

[bat443]

Hi DEM, I have changed the rudder cables on a 55 170b I owned and am currently changing them on a 49 170A I currently own. The clevis end at the front that attaches to the rudder bar has a swagged on ball on the cable. I have removed the cable both times by pulling the old cable out the front with pull wire attached and then pulling the new cables in front to back. The swagged on turnbuckle end will not pass through the fair leads in the aft fuselage nor the pulleys. You will have to remove the 4 pulleys in the aft fuselage and the cotter pin which guards the cable on the forward pulleys collocated with the pulleys for the aileron cables in addition to removing the fair leads you are speaking of. In both cases I have removed the rudder, elevators, vertical stabilizer and horizontal stabilizer to access the fair leads in the aft tail cone. I have also used this opportunity to replace rusted and worn hardware including the NAS bolts which attach the aft spar of the vertical fin to the horizontal stablelizer. You can also clean out the 60 years or so years of dirt. This is also a good time to clean and paint the elevator and trim tab push pull tubes. You should also be prepared to replace the screws which attach the cable clevis to the rudder bar connection as I have found them worn in both cases, the 55 which had 5500 hours were more than 50 percent worn though and the 49 with 2300 hours are worn about 20 percent. I am sure I have told you far more than you wanted to hear and I am also sure that others have replaced the cables without removing the tail but I have not. Someone needs to design and STC an access panel kit similar to the one for the trim screw access on a 180/185.

best of luck, Tim

[flyboy122]

Tim,

Thanks! Turns out the back end was the easy part. After getting my arm stuck in the inspection hole by the fin (and of course my cell phone was on the work bench.....) I laid a 2x8 on the formers and just crawled back there. Not bad at all, and gave me a good chance to really inspect/clean/lube things. Turns out the pulleys were gunked up and barely turning, so cleaned those all and got them spinning nicely again. Drilling out the fairleads was easy and quick, and as soon as I remember to bring my universal socket to the airport tightening the nuts on the replacement screws will be straightforward.

The big challenge turned out to be on the front end. Working entirely through the inspection hole, removing those cotter pins on the pulleys was a challenge! Finally a determined effort with a side cutters was able to just brute force wrench them out. Next was getting the cable end past the pulley. For some reason there was just not quite enough room. I light tug got them out, but the other way was more problematic as I didn't want to pull that hard on a string. I ended up fishing a piece of welding rod through and hooking that to the new cable end. After some jiggling/fiddling/positioning, I was able to get them back past the pulley with another light tug.

Of course I forgot to order new clevis pins when I ordered the cables, and of course mine are stepped. I'm in the process of searching hardware bins at various airports for a pair AN23-10 pins so I can fly this weekend. In the meantime I'm trying to figure out why just a pair of AN bolts won't work? Seems like there is clearance. I'm sure there is a reason.....

DEM