Actually one more thingÖ
As others have mentioned check under the step as there is a thin piece of sheet metal that likes to come down and allow pebbles and rocks to lodge in there and not allow the step to close fully. Stupid design as this shouldíve been completely sealed. Iíve used a leaf blower in the past to blow out small rocks and debris.
What I did temporarily until Iím able to take the whole thing down, fix the sheet metal overhang and go through it is put some insulation very sticky Zip tape to cover this area. Itís very tight to get one complete piece of tape the width of the step as this is what you want.
What I did was place the Zip tape on the very end of the step upside down so that the sticky part was on top. I bent over the ends to the side of the step so that it would stay down. I then cut a quarter of the the tape with a blade. I didnít want it the full width of the tape as I wanted to be able to stick the tape to the underside with a scraper and screw driver.
I closed the door and with a long screw driver, I held up the sheet metal flap so that the tape didnít get caught. When the step was in, I then secured the tape to the sheet metal and cutoff the ends. For now this has been working until I get a chance to take it down.
While youíre at it, you can also lubricate the chain. I lubricate it from the top with the step extended and from the bottom with the step retracted. From the bottom, I just slightly pull down on the plastic shroud and inject the lube with the nozzle and can get pretty good coverage of the chain.
I use Kwik Lube and works great. i use it lube the sliding door too.