Hi George,
Pictures in these cases help so we can see what you are up against. What year 286SR do you have? Remembering I thought the T280SR front kitchen was last made in 2005 and was replaced the T280SR in 2006. So if I have this right you are looking at a 2006 or a 2007.
The good news is very late in the 2004 model year, for sure in the 2005 and newer, Sunline upgraded the slide floor and trough system. Mine is a early 2004 vintage and used the older system setup. Still good but the 2005 upgrades are better.
And yes slides have been known to be out of adjustment. They do have a need to keep track of and when something like you are describing occurs it should be adjusted for soon after it is found. The concern is water intrusion.
The adjustment once understood what does what and what order to adjust them in is not that complex if you are mechanically handy. So do not fear the slide. Once adjusted proper they do stay adjusted right for a real long time. We are talking years of time. Many times they become out of adjustment due to something coming loose from vibration. And then they either are let go as the owner never noticed it or worse adjusted wrong.
We can help walk you through the adjusting process for the future if you get the camper.
Now to the water damage you are describing. Do you know how many inches stuck out as the one side? A 1/2", 1", 2" (yes I have seen other campers 2" hanging out...)
Did the unit have a slide topper on it?
By the slide not closing all the way moisture could have worked it's way inside. The wet is what may have lifted the wall paper.
I would not be so concerned about the actual slide mechanism, if they adjust it correctly it should hold. While they may not warrant it, if they can at least assure you they will fix any broken slide mechanism parts if there are any and properly adjust the slide to close and fully open correctly that is a big step. If they do this much then the lack of warranty is not some much a concern. A dealer warranting a used camper, good luck.
Odds are good the slave rack end slipped in the slide arm holes and the slide hangs out when closed.
Looks like this adjustment
It is mounted here
Or the master rack loosen up here at this thread rod adjustment. But I'd check the slave rack first as that is the most usual spot.
The bigger concern is the water damage. Did you feel anything damp? Smells like rot or heavy moldy musty odor? Put your nose right down there and sniff and poke around feeling for soft wood. A prior wet spot that has dried up still may have some odor to it but a still wet one will make you gag up close and feel damp. Take paper towels they can wick up moisture to see if there is any.
With the slide out, lift the carpet flap and looking under it in the corners. Feel for soft wood, even take an ice pick if he will let you probe. If you have a bad situation and can push an ice pic in 2 inch or more, well it got rot. Solid wood is solid and an ice pic will not go in much if any. 1/32" to 1/16" maybe and that is pushing it on solid wood in the frame. The 1/8" thick luan wall, well don't push to hard on it.
The key is you know what your buying and if there is signs of water damage you can use that as a price negotiating point. Having fixed my own slide floor from rot everything is fixable. However the big difference is if your handy with wood working or not. If you are handy you can do the work and your only paying for materials which in the big picture is not a lot. If you have to hire this work out, if the damage is a lot it can add up quick at $95 to $110/hr. If all you have is some curled up wall paper and the wood is sound, that is not a big issue to deal with. If the lower part of the side of the wall has a considerable amount of rot that can be more of an issue. But again, all is fixable
For me, if the price was right and I wanted that camper and I know what was right or wrong, I may still buy it but at a reduced price. The dealer may not even know there is a rot problem.
We had a club member here buy a 5th wheel. From the club he knew to look for slide floor rot. He pointed it out to the dealer, it shocked them and they put an entire new floor on before he took the rig. Do not know if yours is this big of an issue, but heads up go looking.
On the 286 if it is a 2006 or 2007, look at the very end of the slide for soft wood. Again take the ice pic. The newer floors had a plastic coating on them which protects the bottom of the floor. But the ends have tended to wick in water.
These are 2 pics of a 2005 slide, and on a T280SR no less...
The black edge can crack if left exposed outside all the time and water can wick in the cracks and rot the floor. The prior vintage that use Darco membranes had other issues. If the wood is hard, then no worried you can seal up the end later.
Hope all this helps and good luck with your camper.
John