I just got finished tightening the spring on a slide out cover (NOT the awning). I have Carefree slide out covers, 2002 vintage.
I wish I had taken pictures or video of what I did,because there are no instructions anywhere that I could find online to show how to tighten up the springs only. There are plenty of instructions on replacing the fabric, tho.
The left hand side (as you are looking at the slide out from outside) was the side with the spring tension on it. Take off the end cap and unscrew the one screw holding the bottom panel on to get access to the set screw that holds the bracket in place. It's a small screw and easy to drop. Mark the end of the bracket before taking off so you can slide it back on in the same distance. I slid out the bracket from it's holder but hold tight,because of the tension. Once I had it out, I let off all of the tension off of it because I wanted to start from scratch. Then I rotated it 14 times,(I just turned 65 and I could hold it with no problem) put a nail or a small screw driver in the hole that aligns when the bracket is where it will slide back on and slid it back on to the mark I made. Replace set screw, screw holding the bottom panel and replace the end cap. I was a bit leery about pulling out the end so far to get it out of the bracket attached to the slide out, but it worked out fine. There is no more slack with slide out open or closed. I had replaced the fabric on both slide outs, and I think the new fabric may have stretched a bit over time. post some pics if you need any more help.
