Re-establishing the basics:
The top step is attached to two "L" shaped bracket that have posts (or shoulder bolts) located on either side near the top of the "L" bracket. The posts ride or slide in a banana shaped groove or channel cut into the outrigger or frame extension that supports the step. This is the framed compartment that supports the step assembly.
When examining the banana shaped channel that the post rides in there are two things that make the operation of the step work well or not, assuming the channel is not bent. At one end of the banana shaped channel, closest to the outside edge of the coach there is a hook shaped notch that the post (or shoulder bolt locks into when the step is pulled out and downward pressure is placed on the step. It is a stop that conforms to the round barrel shape of the post or bolt mounted on the "L" shaped step bracket. It that notch is worn unevenly or bent or damaged in anyway or is different than the other side, the step will not lock evenly from side to side and it will wobble or disengage. If it needs to be adjusted, this notch can be shaped carefully with a rat tail file to allow the post to fit more evenly on both sides.
If the step will not stay put when it is locked out of the way for travel, it is the fault of the other end of the banana shaped groove or channel that the posts ride in. On that end, and associated with that end there is a swing arm that is operated by the chrome knob on the right of the entry step. The knob, when depressed engages a "Y" shaped swing arm (or near enough to a Y shape) linkage that swings into the travel path of the post or shoulder bolt. This bracket must swing in place to block the path of the posts on the "L" bracket equally on both sides for the step to "lock" into place and remain stable and secure.
If the left side needs adjustment (up or down) take a crescent wrench and adjusted it (1/4 inch or so) so it fits the linkage (which is square stock) and near the left grommet carefully bend it
up or down so it blocks the path or clears it, either way. On the right side you can carefully bend the mild steel link the chrome knob attach's to so that it hits the door frame sooner or later to allow the link to block or clear the path. I ended up taking a file and increasing (by 1/8 ") the swing of this link upward to adjust the step. It works great now.
My step was ripped completely off by the PO's in some wild repossession attempt by a jealous relative
(his brother) left out of the will. Whoo hoo ! I can see it now, lawn chairs and coolers, shore power wires and hoses snappin and flappin, whippin and rollin.... The coach was pampered for years and I think I found her in time. She has a bright future
ahead of her... complete restoration underway