Comprehensive Diagnosis & Field Repair Solution
Abnormal swing movement, including slow rotation, uneven speed, stuttering, or a general lack of power, is a common and disruptive issue in excavators. This fault directly impairs work efficiency and typically points to problems in the swing motor, brake system, or hydraulic control circuit.
Common Cause & Repair: Stuck Swing BrakeThe most frequent cause of this issue is a swing brake that fails to fully disengage. Designed to lock the upper structure when stationary, a brake stuck due to insufficient pilot pressure, worn friction discs, or component seizing will result in slow or weak rotation.
Repair Steps:
Disassemble the swing brake, clean internal parts, and replace worn friction discs.
Inspect and test the brake release oil pressure to ensure proper operation.
Additional Checks:
Swing Motor Internal Leakage: Test circuit pressure and flow to confirm motor efficiency. If internal leakage is confirmed, overhaul or replace the motor.
Contaminated Hydraulic Fluid: Check oil cleanliness; replace dirty oil and filters immediately.
Stuck Control Valve: Inspect and clean the main control valve spools; replace if worn or damaged.
Post-Repair Test:Conduct swing function tests under both no-load and working conditions to ensure smooth, powerful, and stable rotation.
