I broke a boarding step-extension cable a few years ago. I went to a local business, Delta Cable, and had a new cable made. It was nothing more than 1/16" twisted-strands steel cable with a ball swaged onto the end. I got stainless. I got it way too long on purpose. I tinned the "bare" end with solder to keep loose strands from catching in the cable housing as I fed it through. Starting from the nose gear tunnel, feed the tinned end over the little pulley and into the end of the cable housing. It's pretty much a straight run to the where the cable housing goes past the rear cabin bulkhead. That's where the "inner" cable caught and would not go the final 7 or 8 inches because the housing bends upward. I removed the aft end of the cable housing from its attach point so I could lay it our flat toward the tail cone. Yes! The cable went the rest of the way through. Reattach the aft cable housing end.

Figure out a way to hold the step extended. I cut a full length slice out of an 11" long piece of 2" inside diameter ABS plastic pipe (leaving a C-shaped section when looked at from the end of the pipe). Pull the step out and slip the pipe over the shaft of the step. I cut the pipe a little short, so I could adjust step extension with shims (electrical tape over the end of the pipe). Secure the forward end of the cable to the nose gear leg (don't forget the shear link!!!). The attach point is a lug held onto the nose strut with a nut. I think it's easier to assemble the cable end & shear link hardware to the attach lug, and THEN poke the attach lug through the gear leg and install the nut on the lug's threaded end.

Loosely attach the aft end so that, with the gear down, the step is almost totally extended. You want about 1/8" to 1/4" of extension travel level left when the step is extended. Enough that the cable is held in tension by the step retraction springs only - not stretched because the step is all the way down before the nose gear is all the way down. But, don't leave enough margin that the step moves too much when you step on it. I can see someone put their weight on the step and suddenly it extends another inch. The person's foot could easily slip off the step and their skull dent your flap and bloody the ramp.

As I said, I did this a few years ago. Then last week, during a gear swing while on one of Linn Kastan's awesome Beech jacks, the swage failed and the step sprung to the retracted position. Startled the crap out of me. I figured the shear link had broken, but it was intact. I found the swage ball on the floor. The guy at Delta Cable took a look at it and said that whoever did the swage, didn't crush the ball on well enough.

Unfortunately, the forward end of the cable went into the end of the housing and I could not pull it through to attach a new ball (which would have been difficult, anyway, with the cable still in the airplane. The end where the ball had been also unraveled a little, making it hard to pull the cable out from the aft end. But, I pulled harder and it came out.

Delta Cable made me a new cable. $6.31, including a better swaged end. I will install it next week. If you need, I will take some pictures of the attach points in case you have difficulty figuring out how the thing attaches. The front end is pretty easy to figure out. The back end is odd because the 2 springs do not attach to the same pieces of hardware on both ends.

When you have a cable made up, anything larger than 1/16" won't fit in the housing and the next size smaller (3/64") might not be strong enough.

If you can't feed the cable through the housing, you're somewhat screwed.  Getting to the old housing to remove & replace has got to be a total PITA. It runs along the belly under seats & floor boards and goes through access holes in the spar boxes. It goes under the aileron cable system. I was hugely relieved when I was able to thread the new cable through the old housing.

Larry