Rudder cable replacement help

[7698]

We found some fraying of the rudder cables under the first pulley so I am in the process of replacing them..

Have removed the two pulleys to allow the cable to be drawn through with a cord attached so that I can pull the new cable in using it. However, I cannot remove the cable at the rudder end as there looks to be a bush arrangement that is preventing it from pulling through...

Its a P shaped bracked close to the rudder cable exit slot. The circular section of the P shape looks to have a paxolin bush in it that is flanged at one end to prevent is pulling through the P and a safety wire at the other preventing it coming back through the other way when in normal use..

I am assuming that the bush is split to allow it to fit over the cable (as the new McFarlane cable doesnt have this bush fitted already to it) but I cant see a way of getting it off..

If I remove the lock wire, should it just push through? It doesnt appear to move when pushed but could just be tight with dirt etc?

Any assistance very welcome..

[2066]

It's been a few years, but -- yes, it's in two pieces/split and it'll "slide" out...BUT is likely cinched in there pretty tight in addition to the safety wire "holding" it. I took that opportunity to remove the horiz. stab for access -- not a big deal, incidentally, and I realize you may already have adequate access(?). Hope the pic will help. Mac

IMG_1473.jpg (49.05 KiB) Viewed 3247 times

[7698]

Mac, Thats awesome.. Exactly what Iwas looking for.

I was hoping that I didnt have to remove the Stab to get access but that may have to happen... My only access is through the cable outlet slit which may prove to be too difficult.

[2066]

"...remove the Stab to get access but that may have to happen..."

Probably...unless you were fortunate to have (larger) access/inspection holes back/under there...OR, if you can convince a talented surgeon who's experienced in "laparoscopic surgery" and has the tools to help . Seriously, I have seen a couple of 140s over the years with inspection holes back there that enabled access to the guides -- but, it'd likely require removing the stab to cut and fab (maybe for "next time"?). You mentioned already having the cables -- some have fabricated cables that enabled pulling through without end connections already on and installing/swaging afterward. Someone might yet wade in with a practical alternative -- if not, removing the stab does present a good opportunity for inspecting an area that you don't normally/easily see. Good luck! Mac

[V529]

Under "normal" circumstances, the stab has to be removed. Sorry...............but that's the way it is.

[7698]

Sorry, but I really struggled with the thought of removing the tail surface to get at these bushes... So please dont shout back at me but I had a go at the keyhole surgery method...

I did the usual stuff of removing the pulleys and attached cord to the old cables and pulled it to the bush in the tail. At this point I removed the safety wire loop at the end of them with a pair of long nose pliers... I had a look at the bushes and assessed how or if they would move by tapping them with a flat ended punch... Gently I may add... Nothing happening, based on your comments on how stiff they are.. So I cut the old cable off and pushed the cable back through the bush with a punch of the same diameter... Using the same punch, whose shaft diameter was just smaller than the P section of the bush holder, tapped the bush until it started to move.

Using a peice of tubing and cord I made a "snake catcher" and used it to put a holding loop around the protruding bush section and pulled it tight just so the bush doesnt fall into the fusalage. Once this was in place i continued to tap the bush out. I forgot to say that I am using the slots in the rear fusalage where the rudder cables exit to gain access.

At this point I pull in the new cable with the aid of the cord. When in I pull a good loop of cable from the back of the P section (fusalage end) through the cable exit slot so that I can put the split bush onto it and use the snake catcher again to hold in place... Grease the outer of the bush so that it goes in a little easier than it came out and push the cable back into the fusalage... Using the snake catcher from the opposite side I can, with some fiddling about get the bush in place at the reqay of the P section...

This is where it gets even more fiddly... Invent a new tool called a "scranner" which is a 3/8 spanner taped to a screwdriver for length... putting the C of the spanner over the new cable I could gently push against the bush to start it going into the P section.

Invent a new tool with no name, but basically an old flat steel spanner that came with some flat pack furniture, bend it over at the end and cut through to make a C end... Its too short so attach some thick safety wire as a pull...

Another very fiddley bit, but put the modified flat spanner through the cable slot and hook it over the cable close to the rear of the bush and pull the bush into the P section...

Its taken me the best part of 2 days, but the cables are now in...

[2066]

Congratulations! If for any reason the day job doesn't work out, you're now well qualified as a very talented and experienced "laparoscopic surgeon"! Thanks for sharing the expert & innovative problem solving! (...not shouting, but it took us less than 3 hours to R & R the stab....still, you've accomplished what many have considered "impossible" & there are times when it may probably be the only "practical" method? In any event, you've now "invented" it!). Yep, Congrats! Mac

[7698]

Thanks Mac..

I guess I had no idea about the process of removing the stab...

Would that have involved removing the fin, rudder and associated control cables etc... What would be the sequence?