have a hustler model 939207 the belt tension spring has broken 3 to 4 times. have replaced all deck pulleys and deck belt any clues as to why the spring continues to break
Try a section of rubber hose that slides snuggly over the spring. I had a machine years ago that would break springs like you described until an engineer gave me that advice. I never had another problem after I did that. It has a protective and dampening effect.
mine had noise due to harmonics and that may be what is breaking yours, I split a hunk of pool noodle and ip tied it around the spring, that stopped it.
You can also "pack" the spring with silicon sealant.
Any cheap sealant will do the job.
Doesn't have to be the whole spring just a good thick strip down one side will work.