A logistics yard reported that a JCB 116R electric forklift shuddered violently when the steering wheel was turned to full lock. The vibration could be felt throughout the chassis.
The technician inspected the "Rear Steer Axle." The "Pivot Pins" (the shafts allowing the axle to oscillate for ground clearance) had worn out the bushings. There was 5mm of play. This play allowed the entire rear axle to "shimmy" when the steering force was applied at full lock.
He also checked the "Steer Tires" (small solid rubber tires). The left steer tire had a "flat spot" (uneven wear). When the tire rotated to the flat spot, it caused a bounce, which was amplified by the worn pivot pins.
The repair involved replacing the "Steer Axle Pivot Bushings" and "Pins." The flat-spotted steer tire was replaced. The "Steering Cylinder Mounting Bolts" were also checked and re-torched. After the repair, the steering was smooth, and the chassis shake was eliminated.
