cep
I don't have an idea what is wrong with the bottom of the slide.
But, I had one with just the fabric on the bottom and it slid on framework - no roller. So the bottom fabric started wearing out.
I noticed that the slide had clearance to be lifted up while still in the RV. So i cut my sheet metal to the size i wanted it. Jacked the slide up slightly With (slide almost all the way out) - Think I used something like a 2X6 for weight distribution on the slide. Slid the sheet metal between the slide bottom and the support. Got it where I wanted it. Let the slide down. Secured the outer portion of the sheet metal with countersunk screws. Slid the thing all the way out and did the inner portion of the bottom.
That was a bazillion years ago and i do not have a clue where the rig may be now.