X2
Metal fatigues. The older the coach the more metal fatigue on the leaf springs.
On my first used MH I added a leaf to each side. WHAT a difference. No more tail dragging into gas station driveways. And it improved my handling tremendously.
If you have one side sitting that low, sounds like one of the leaf springs broke. BTW you can look at the leaf assembly and see all of them in place where they are strapped in and STILL have one of them cracked in the middle and it just did not fall out. But it now does not have the correct support.
I took mine to a frame shop that specializes in stuff like that. They had a whole mathematical equation computer system on what to correctly install. It was 'not' that expensive either. Stay AWAY from taking it to any RV dealership and/or RV repair shop.