Aquanaut 400 not vacuuming whole pool

[fhorta]

Hi all. Suction cleaner pretty much turns and pivots on left wheel. Does on right wheel too, but not as much. Rarely goes to the shallow end , hangs around deep end. No change to suction, pump pumps pretty good. Wondering if has something to do with possible wearing out of parts , how i can determine if that is the problem and where I can get parts for it?. I have spare rubber tires.