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If the manufacturer is still backing the 5 year warranty period, why would the dealer walk away? Also think they could at the very least offer a suggestion to help remedy the issue (i.e. Support on the bottom). Sounds like a tough situation all around,hard to point blame not knowing all the facts, but I'd just expect the dealer to lay out a few options, even if it involved cash out of pocket for the customer. Some solution would be better than no solution.
Because the dealer doesn't make warranty determinations the manufacturer does.
What happens if the dealer tries to help and tries to stabilize the bottom. If it fails then emerald can easily wash their hands off it and the dealer is now liable.