Most around treats walk behind equipment as an outcast step child. I tried repairing and selling them for a reasonable price to only just get insult offers. Now most that come in just parted out where I make 2-3x the money on the used that I install on those that customers do want repaired.
Personally have yet to see those plastic tubes worn through but it does make sense that it can happen. I have heard the tube getting worn through on the unseen side and causing problems.
