Replacing Cables

How to keep the Cessna 170 flying and airworthy.

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bagarre
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Joined: Thu Sep 30, 2010 11:35 pm

Replacing Cables

Post by bagarre »

First off, at next annual, disconnect the rudder cables at the rudder and pull them ALL the way forward and inspect for broken wires.
95D has 1,400 hour total time and the wires felt like a porcupine. I woudlnt have been able to tell with the cables still attached.

So, I decided to buy a full set of replacement cables.

My plan is to pull each pulley one at a time to prevent mass confusion. Clean, inspect, lube and re-install finger tight. Replace hardware as needed (I pre-ordered a lot)

This allows me to make one order for bad pulleys but not need to take everything out at once.

I plan to pull the new cables thru when I pull the old one out with a length of safety wire. as the new cable passes each pulley, I will torque that pulley and mark it with yellow paint (torque seal)

I cant tension any of the cables except for the elevator for now.

Pulleys will be lubed with a synthetic bicycle chain lube designed to repel water, keep out grime and prevent corrosion. I chose this oil because bicycle chains endure far more abuse than these pulleys and the stuff is quality oil.

The 100 series repair manual says to leave the cables dry unless you're in a marine environment.

The job seems fairly straight forward if not a little meticulous.

What am I missing?


Also, what are the center to center lengths of the rudder cable straps that attach the cables to the rudder? MIne are missing and I need to fab a set.
bat443
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Re: Replacing Cables

Post by bat443 »

Replace the AN23 clevis pins (look like a screw with slotted head) everywhere used. I have replaced the rudder cables on a 170B with about 6000 hrs and the forward ones that attach the cable to the rudder bar were worn 50% through, and a 170A with about 2200 hrs that on it the same pins were worn about 20%. These never get checked and would make for a bad day to say the least if they were to fail.

Tim
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c170b53
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Re: Replacing Cables

Post by c170b53 »

There's going to be some "moments" when you say things that can't be printed. The pulley clusters around the top and bottom of the rear door posts have spacers- washers between the pulleys (I believe ), try to take pictures if you can. Unless your project was previously sunk, you'll likely find most of the pulleys are ok. Then again environment is everything so I like your approach to inspect it all. I think you'll find the pulleys for the flap cables (and the cables themselves) outside of the fuselage at the rear spar might as you suspect be compromised by dirt and age.
Commercially, we used protect amber to coat cables to extend their life. I think for our planes, that would be overkill. I wouldn't use anything myself to flush out the grease in the pulley bearings, or use anything that would flush out the internal lubrication in the cables themselves.
FWIW, my BIL, a former bicycle racer in France, also raced for Team Monaco, calls WD-40, the racers edge. Cans of the stuff can be readily found around, you guessed it, red airplane's.
Jim McIntosh..
1953 C170B S/N 25656
02 K1200RS
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c170b53
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Re: Replacing Cables

Post by c170b53 »

I'll guess 2.5 inches for the links but it will be a week until I can measure mine.
Jim McIntosh..
1953 C170B S/N 25656
02 K1200RS
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n2582d
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Re: Replacing Cables

Post by n2582d »

Also, what are the center to center lengths of the rudder cable straps that attach the cables to the rudder? MIne are missing and I need to fab a set.
David, search the p/n 0310219-2 and you'll find this missing link discussed in the past. George measured it at 1.75", Bruce measured it at 1.785" and now I measure it at 1.77". Total length is 2.33".
IMG_0316.JPG
Gary
bagarre
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Re: Replacing Cables

Post by bagarre »

n2582d wrote:
Also, what are the center to center lengths of the rudder cable straps that attach the cables to the rudder? MIne are missing and I need to fab a set.
David, search the p/n 0310219-2 and you'll find this missing link discussed in the past. George measured it at 1.75", Bruce measured it at 1.785" and now I measure it at 1.77". Total length is 2.33".
IMG_0316.JPG
Thanks. I have no idea where mine went as they were on the plane when I took it apart :(
I'm sure they are in a ziploc baggy, neatly labeled somewhere but I cant find them.
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n2582d
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Re: Replacing Cables

Post by n2582d »

Yeah, they come out of hiding once you've bought or made their replacement. :x
Gary
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GAHorn
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Re: Replacing Cables

Post by GAHorn »

Whatever became of par al ketone for cable protectorant? :wink:

http://www.aircraftspruce.com/catalog/c ... ketone.php
'53 B-model N146YS SN:25713
50th Anniversary of Flight Model. Winner-Best Original 170B, 100th Anniversary of Flight Convention.
An originality nut (mostly) for the right reasons. ;)
bagarre
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Re: Replacing Cables

Post by bagarre »

gahorn wrote:Whatever became of par al ketone for cable protectorant? :wink:

http://www.aircraftspruce.com/catalog/c ... ketone.php
I might wipe down the whole tailcone with that stuff.
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170driverpsw
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Re: Replacing Cables

Post by 170driverpsw »

I am also in the annual process and are changing out my elevator cables on a 1951 C170A 19942. My A&P is going to make the cables and since the current ones have stretched we are unable to get an exact length on the cables. Does anyone know the proper lengths of these cables both top and bottom on the A models?
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n2582d
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Re: Replacing Cables

Post by n2582d »

170driverpsw wrote:Does anyone know the proper lengths of these cables both top and bottom on the A models?
Josh writes about this here.
Gary
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