Probably the hardest type unit to replace step chains. You can do it several ways. It can be very dangerous, especially if you don't have a runbug/pendant. First, I remove the inner deck skirt covers on both sides up past the end of first straight section of skirt walls on both sides at the beginning of the incline. Then remove the first section of skirt walls at the beginning of the incline. Then remove all steps. When you get to the last remaining steps to be removed, you have to be very safe. LOTO when on the step axles. When all steps are out, back off spring pressure at the tension carriage. Again LOTO. Run a 6 step section into the area where the skirt walls were removed. At this point, I like to make a wooden ramp of plywood with 2 x 4 studs screwed to the bottom that llip over the existing lower skirt walls and fills the void of the missing steps from the combplate to the beginning of the incline. From here, you have a safe area to remove the sections of step chain and walk it out and put in the new. Of course, pay attention to the orientation of the 6 step sections. I had a guy put one in upside down before and it made the entry for the cam lock to face the wrong way. From here, you can put in your new 6 step section, attach it to the existing ends and run the unit up to the the next one to be swapped out. Rinse and repeat.
I've also replaced the step chains by removing all the step chains first. This way you can do a super cleandown. This way takes a larger crew. After the cleandown, I would mount a winch at the top, hook all the chain together and pull the chain up to the drive then use the drive to finish the job of running the chains down and around. This requires additional roping at the lower end to keep the slack out. The piece by piece method is probably more ideal. Either way, it's a long process.
Count steps before ordering. As I said, they come in 6 step sections. So, if your step count is not a multiple of 6 or is ann odd number, you'll need single step sections to make up accordingly.
I hope this gives you a better idea. There are different ways to do it.
