Fault Phenomenon: Komatsu FB15 electric forklift brake pedal feels soft while driving, braking distance increases, and eventually cannot stop.

Troubleshooting Process:
– Checked brake fluid level: level normal.
– Checked brake master cylinder: piston cup not damaged.
– Checked brake wheel cylinders: no signs of oil leakage.
– Checked brake pad thickness: thickness normal.

Root Cause: Air in the brake lines, or the brake fluid has absorbed water and deteriorated, causing vapor lock.

Required Parts: Brake fluid and bleeding tools.