Uneven cutting from riding mower?

Ran over metal sewer cover on lawn causing uneven cutting from blade damage. Replaced blades, but still cutting very uneven. I have height adjustment on highest settings, 5 or 6 the highest. Anything lower causes scalping of turf on one side. My deck wheels don't even touch ground. How do I adjust deck? Craftmans Model #917.271631. LT-1000