Hitachi ZX26U-6 Left Track Comes Off Sprocket
Fault Codes & Symptoms
Track derails from drive sprocket Related symptoms: - Excessive track slack - Grease visible on or around the front idler - Inability to adjust track tension The left track keeps coming off, especially when turning right or working on uneven ground. We put it back on, and it came off again within an hour.
Confirmed cause: Failed track adjuster grease cylinder seal. Repair performed: Removed the front idler and track adjuster assembly. Disassembled the track adjuster and replaced the failed seal and related O-rings. Cleaned and inspected the cylinder for scoring, found none. Reassembled and installed the components. Verification: Grease was pumped into the adjuster fitting. The idler moved forward and correct track tension was successfully set according to manufacturer specifications. The machine was operated for 30 minutes, including multiple turns in both directions on soft ground, and the track remained properly seated. Technician notes: - This is a common failure point. If the track won't hold tension, look for leaking grease first. - Always clean the track frame thoroughly before reinstalling the idler to ensure smooth operation. - Setting correct track tension is critical. Too tight causes premature wear; too loose and it will derail.