I think if you could prove a defect in the pump they might cover it although not likely. What sort of complaints are you seeing on other forums? I have had sureflo pumps in all my Rvs going back more than a decade and other than having a screen cover freeze (not a manufacture default) never had an issue. It would have to be some internal o ring or crack in the housing not caused by freezing. Trying to prove that is almost impossible. Any connection, or cracked line as a result of poor workmanship or freezing would not be sureflo's problem. Not defending them I just think your focus should be placed elsewhere. Like, did the original winterization company actually do it properly? Is there really that much damage and it requires that much work? Your response said the insurance company came out and would not pay, but you still haven't answered why they won't pay. For that much damage to occur it would have to be under pressure with a full tank of water. If you are camping wouldn't you have noticed water running underneath your rig and/or your water pump continually running? In other words, it wouldn't happen in storage and winterized. The system isn't pressurized and the fresh water tank would be empty. So, it would have to happen when you are using it. And that much water would be noticeably raining under the RV. That just seems like an awful lot of damage for a leaking water pump not to notice. A more likely scenario is you have a window or roof leak. Which depending on your coverage may be on you if you can't evidence periodic sealing of all seams and penetrations. Unless you see an actual leak in a line around your water pump, I think the root of your damage is another problem. I understand your frustration, but you need to look at several possible reasons for all this water damage. And why is Keystone covering the slide portion? That seems weird unless they noticed a seam, window, or roof leak/defect. And if they covered that, why not the rest of the flooring? I feel like there is more to this story.
Reminds of something this summer. While in an RV park our neighbor in his 45 ft anthem pusher was parked beside us. It was raining water under his RV. So much so that it was causing puddles in the neighboring sites. He had a leak in his aquahot. I brought it to his attention. How in the world he didn't notice water raining out of his bins and his site filling up is way beyond a head scratcher. I can't imagine the damage but I bet it's similar to yours.