Mixture Cable Caution

[C170U2]

IMG_4541.JPG

Just wanted to give you guys a heads up what I found with my mixture cable. The end of the cable had split where it attaches to the carburetor. This was the original cable and survived 70 years. Glad I found it. It would be something good for you all to take a close look at during your next annual.

Fly safe! Mike

[n2582d]

Mike,
Thanks for sharing that. Quite impressive for that to be the original cable. I was looking at the IPC for the attach hardware for the mixture cable. The bolt called out for in C-170 IPC (fig. 34-46) calls for bolt p/n 0450311-2 and a AN365-428 nut. Standard practice these days calls for using all-metal stop nuts -- AN363-428 in this case rather than the AN365 nut with the nylon insert. I also noted that the C-170B IPC incorrectly shows the bolt here to be p/n 0350311-2 rather than the 0450311-2 bolt it calls for in the earlier model IPCs. If you're looking for that cable to last longer than 70 years you might consider installing McFarlane's MCS2323-2 bolt which has the hole chamfered to reduce stress on the cable. Finally, for those inspecting these cables, here's a discussion about clamps for bowden cables.

[C170U2]

I was hoping I could just go to my favorite salvage yard (Faeth Aircraft) and find a replacement cable......no luck. Those ugly salmon colored knobs seem to be like hens teeth. Here is how I repaired my old cable. I cut the wire off my old knob, drilled out the rod to accept the new wire I found at Faeths, added a dab of hysol, and crimped the end. Stronger than it was before and I get to maintain the look of the panel. I probably could have just purchased a new cable from Spruce and painted the knob but this worked for me. I also rounded to corners of my old bolt in similar fashion to the Mcfarlane bolt and ensured I had movement on the mixture arm. I then bent the extra wire around the bolt. Pretty happy with it.

[DaveF]

Great work, thanks. I've been wondering how I'm going to save the knobs when my mixture and carb heat wires finally break!

[n2582d]

Thanks for taking the time to photograph that repair. Years ago George Willford wrote up an alternative means of repair here.

[GAHorn]

Great example of an “owner produced part”.

[bsdunek]

I was hoping I could just go to my favorite salvage yard (Faeth Aircraft) and find a replacement cable......no luck. Those ugly salmon colored knobs seem to be like hens teeth. Here is how I repaired my old cable. I cut the wire off my old knob, drilled out the rod to accept the new wire I found at Faeths, added a dab of hysol, and crimped the end. Stronger than it was before and I get to maintain the look of the panel. I probably could have just purchased a new cable from Spruce and painted the knob but this worked for me. I also rounded to corners of my old bolt in similar fashion to the Mcfarlane bolt and ensured I had movement on the mixture arm. I then bent the extra wire around the bolt. Pretty happy with it.

Great idea! Wondered what I was going to do when one of my cables fails. I am trying to keep my 170 as original looking a practical.

[cessna170bdriver]

Looks like a good article for the 170 News.