The International Cessna^® 170 Association

Control Cabin Air Push-Pull bowden cables NOT functional.

C 170B s.n. 26433 July 1954 roll out.

When purchase aircraft - not working - advised dress warmly and forget the cables.

Now I want everything 100 % functional. Suspect cables not touched since new 64 years ago.

Must admit I do not follow FIG 55 pg 95 completely. I see two (2) cables 15 & 16 from panel but do not see the separate terminus of both cables.

Could A/P simply disassemble the parts, clean,lube reassemble and all would be right? Do we need to purchase new cables?
I see the sliding plate but don't understand the spring 23 0713019.

Would appreciate forum wisdom on the subject.

Grady,

These cable are Beldon cables. They consist of a steal wire wrapped with a steel coil sheath. Any gum or sticky substance that penetrates the coil sheath will make the cable stick. Rust on the sheath and wire will make the cable stick. A kink in the cable will make the cable stick.

These cables are very serviceable. Start by finding out if it is your cable that is the problem or perhaps it is what ever the cable is trying to move that is stuck. Disconnect the cable from what ever and try to move the baffle (#22) up and down in it's slide or rotate the butterfly (#4) with the lever (#10). If these don't move pretty free figure out why. Probably lack of lubricant. Once you know they work. Turn your attention to the cable. Every couple of years these cables should be lubed. You lube them by squirting your favorite thin penetrating lube on the outside of the sheath and allowing it to seep in to the wire. More stuff on the outside means it soaks through faster. Flexing the cable slightly along it's length causes the coils to open allowing more lube to penetrate faster. Get a helper to pull the knob while you push the wire in carefully with a pliers being EXTREMELY careful not to kink the wire. Get the wire to move. Keep moving it. Keep lubing it. Let the lube sit and penetrate. May take a day or so but you should be able to get everything unstuck.

Obviously getting any lube on most other things about your airplane is not what you trying to do so hold a rag behind the cable your trying to spray to catch it. When your done and the cable is free, use the rag to wipe the excess off the cable sheath.

For lube I like in no particular order. Kroil, PB Blaster, CRC Knock'er Loose and Mouse Milk. These products are made specifically to penetrate and unstick stuff. Corrosion X, a corrosion preventitive and Boe Shield T-9 are also excellent penetrant fluids which I'd use without hesitation. LPS 1 is a thin lube that will penetrate, I'd rather use a product I've previously mentioned though.

WD-40 or water displacement formula #40 is not a product I'd go for for this job but it is better than spit. And I've probably used it more for this application than any of the other products because WD-40 folks are very good marketers and everyone seems to have a can I can find when I'm looking for any of the previously mentioned products.

I’ve used a lot of WD-40, but it’s annoying because the pushbutton is either off or full blast. LPS is easier to apply in exactly the amount you want. ACF-50 works great for this, too. As Bruce said, spray or swab it on, then work the wire around. Might take repeated applications.

I agree with Bruce and Dave, but more and more I'm turning to Corrosion X or ACF-50 as a longer-term lube for things like this, although I'm a huge fan of Kroil (the Aerokroil spray version) as a penetrating oil. I think Corrosion X or ACF-50 lasts longer on the surface. I would break the cable free and really work it with Kroil or one of the other penetrants mentioned by Bruce and then give it a final spray/lube with Corrosion X or ACF-50. Don't bother with WD-40 for any long term lubrication. It just doesn't last.

IMHO, the Cabin Air cable, the one that operates the sliding door, is a safety of flight item. That door is stainless, and it’s purpose is to isolate the engine compartment from the cabin in case of an engine fire. I have a feeling that there are a lot of folks out there flying 170s that don’t realize that. I wouldn’t fly an airplane with one that didn’t work.

PS, the cable is a Bowden cable. Belden is a manufacturer of electrical wire and cable.

Bowden cables are so simple ...but when they jam... they have usually been abused, have dirt embedded, or have been kinked, and if a little spray lube doesn't fix it...it's so easy and inexpensive to replace them with new ACS cables from Aircraft Spruce. the A-730 cables are excellent and the knobs can be painted any color you like. https://www.aircraftspruce.com/catalog/ ... ey=3010495

The A-740 cables are also excellent if you like a "ratchet" stop type of cable. The ACS cables are Teflon-lined and really "glide free" forever....never needing lube.
My favorites.

I just replaced my starter pull cable with an A-730. I plan on replacing the cabin heat as well. Knobs match the originals pretty much.

cessna170bdriver wrote:IMHO, the Cabin Air cable, the one that operates the sliding door, is a safety of flight item. That door is stainless, and it’s purpose is to isolate the engine compartment from the cabin in case of an engine fire. I have a feeling that there are a lot of folks out there flying 170s that don’t realize that. I wouldn’t fly an airplane with one that didn’t work.

PS, the cable is a Bowden cable. Belden is a manufacturer of electrical wire and cable.

Absolutely agree that people understate the importance of firewall continuity. Also, it’s your only real line of defense against CO poisoning.

Grady,
Until it is repaired the knob(s) should be labeled “inop.” In addition to the gullotine being secured in the closed position, the butterfly valve should be in the cold position according to the Owner’s Manual. This is to avoid cooking the ducting from the muff. In the cold position hot air from the heat muff is vented overboard.

cessna170bdriver wrote:... PS, the cable is a Bowden cable. Belden is a manufacturer of electrical wire and cable.

But Bowen Bruce said “Beldon”.

cessna170bdriver wrote:PS, the cable is a Bowden cable. Belden is a manufacturer of electrical wire and cable.

Belden, Bowden, Bowen, tough to keep them straight.

n2582d wrote:

cessna170bdriver wrote:... PS, the cable is a Bowden cable. Belden is a manufacturer of electrical wire and cable.

But Bowen Bruce said “Beldon”.

And we all know how well Bruce spells, don’t we!

I have always thought that Bowden cables were ones with twisted steel inners (they were invented by Mr Bowden for bicycle brakes), whereas the cables we use have solid steel inners which can push better. Not sure what they are called though?

daedaluscan wrote:I have always thought that Bowden cables were ones with twisted steel inners (they were invented by Mr Bowden for bicycle brakes), whereas the cables we use have solid steel inners which can push better. Not sure what they are called though?

Thanks, Charlie, I wast aware of their history. I’ve always heard the push/pull cables like those in our airplanes referred to as Bowden cables. Aircraft Spruce (not the definitive reference ) uses that nomenclature. Wikipedia at least acknowledges the term to include the push/pull cables used in aircraft.

I always called them choke cables.

Merry Christmas!