My L4240 seat bottom rusted out. I purchased the tractor used, so that's part of the deal, you don't know what you can't see.
The seats are made to look nice, but they have a plastic pan on the bottom with no drain. When water gets on the seat it will eventually cause rust.
I took the seat bottom off thinking I could rebuild what was broken, but it wasn't broken....just rusted out.
If anyone needs the back to one of the L seats, I have one I will give you.