A pipeline contractor reported that a JCB JS210 excavator slowly crept forward when parked on a flat surface, specifically the right track. A loud "clicking" noise was heard from the right final drive when driving.
The technician first tested the "Track Drift." He raised the right track off the ground and engaged the travel lever. The motor stopped immediately when released. This indicated the hydraulic "Anti-Reaction Valve" (brake) was functioning. The drift had to be mechanical. He inspected the "Track Adjuster" (grease cylinder). The grease fitting was leaking, and the adjusting rod was retracted fully. The internal "Adjuster Seal" had failed, losing tension. The track was loose, allowing the drive sprocket to jump teeth under load, which appeared as creep.
The "Clicking" noise was investigated by draining the "Final Drive Gear Oil." The oil was full of metal flakes. He removed the final drive cover. The "First Stage Planetary Gear" had a chipped tooth. The chipped gear was binding against the ring gear under high torque, creating the clicking sound. The binding gear forced the track to move even when hydraulic flow was stopped, contributing to the drift.
The repair involved replacing the track adjuster cylinder seal kit and re-greasing the track to proper tension (300mm sag). The final drive planetary gear set and ring gear were replaced. After reassembly, the clicking stopped, and the track held its position firmly when parked.
