[thefulminator]

I had a similar but not as severe problem with this on our 2013 250RS. I found that the front edge of the liner was installed only with double sided tape which would occasionally come loose. Ended up tracking it up with short stainless screws along the front edge. After looking at the other edges, I decided to track them up the same way. Used about one screw per foot just to make sure the liner stays where it is supposed to be. Had the entire liner drop out on our prior trailer a 2008 21RS and it was quite a job getting it back in place. It had a manual slide and different construction which made the job harder.

 

[thefulminator]

There was already double sided tape on mine. That was the only thing holding the liner up in the front. I stuck it down again and put a row of screw about an inch from the front edge and a foot apart. Just need enough fastening to keep it from sagging.

 

[thefulminator]

The quantity sounds right. I think I used 6s or 8s. 8s will have a larger head so more area to hold up the liner. It may not matter much. The heads are pressing the liner back on to the double sided tape and helps keep it stuck, not letting it droop. I used the shortest screws as I could get. 3/" or 1/2". Not sure which. There was plywood that the double sided tape was stuck to at the front edge. I just can't remember how thick it was.

 

[thefulminator]

Here is what it looks like.