It sounds like you may have wound the spring in the wrong direction. Is the spring snapped?
To your questions, you do not have to buy an entire new awning, but you might have to do some hunting; you should be able to get the left and right spring cap assemblies. But the hunt may be a big deal as the supply is drying up. The issue is that Sunline's series of A & E awnings are no longer made the same, and it seems Dometic is discontinuing making certain parts for them. The last one that left Sunline used was in 2006. I ran into this this spring. I could buy the non-latched end spring and end cap, but getting the latch end was hard to find. Thankfully the friend I was helping, I was able to get his latch end to work right, and we did not have to buy a new latch mechanism.
First off, what series end caps do you have? Several iterations ended up on a Sunline as A & E often changed the design. Can you post a few pics of the end caps and how they attach to the awning arm?
Pending the vintage you have, you might be able to find parts or convert to the next newer style that will still fit in your awning arms.
Hope this helps
Current Sunlines: 2004 T310SR, 2004 T1950, 2004 T2475, 2007 T2499, 2004 T317SR
Prior Sunlines: 2004 T2499 - Fern Blue
2005 Ford F350 Lariat, 6.8L V10 W/ 4.10 rear axle, CC, Short Bed, SRW. Reese HP trunnion bar hitch W/ HP DC
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