Geoff, your situation begs the question "What changed?". I assume that the slide was working correctly and then suddenly didn't. Am I missing something?
This issue is also interesting because I've replaced the toppers on all of my slides and considered adding more tension. Since the new toppers were somewhat shorter in length than the original ones, I decided that they would effectively increase the tension slightly and therefore left the tension as is. So far, I'm not having any problems.
Bob Bowers (Surprise, AZ)
2003 Alpine Coach 40' FDTS
2014 Jeep Cherokee Lattitude