Return to Master Table of Contents Pressure should stay consistently above 2.5 bar (36 psi). If pressure falls below the recommended minimum level, forceful acceleration of the swing motor could lead to cavitation of the circuit and stalling, slowed rotation, noise and possible damage. 2. If main inlet and outlet pressures were off in the preceding tests in Step 1, adjust swing relief valve pressure. Following adjustment, repeat the operating pressure tests (with gauges connected to the inlet and outlet test ports on top of the swing motor) and check pressures with the swing locks engaged and released.
If pressure adjustment fails to restore adequate performance, proceed to the Troubleshooting - Swing table. 3. If pressure tests were at recommended levels through the main inlet and outlet ports, and through the "SH" port of the swing brake, the causes of poor swing performance could include a faulty swing motor, drive train overloading or gearbox defect, or a problem in the brake assembly or swing control valve. Proceed to the troubleshooting information in the next procedure. If pressure through the "SH" port was tested below the minimum 4 bar (58 psi) level, check the shuttle valve in the rear compartment behind cabin.
When pressure through the port is at the recommended level, the brake release valve should disengage the swing brake, allowing the swing motor to rotate the excavator. If pressure adjustment to the valve has been restored but the brake still fails to release, the brake piston or friction plate may be frozen, requiring disassembly of the motor and parts repair/ replacement. 4. If pressure tested at the motor makeup valve falls below recommended minimum level, and consequent problems with cavitation, stalling and surging are observed, check the restriction valve.
If pressure adjustment to the valve has been restored but if problems with cavitation continues, disassemble the upper swing motor housing and clean or replace assembly components as required. NOTE: If all tested pressures are at or above recommended levels, and there are no mechanical problems in the drive train or in the motor/brake assembly, the problem will require further hydraulic troubleshooting. It’s also possible that a defective joystick, an intermittent short in an electrical control circuit or a problem in the e-EPOS circuit is causing diminished swing performance. Pull out the e-EPOS indicator panel from underneath the operator’s seat and perform the self-diagnosis test.
If the display panel reads code "0.2," it is reporting that the swing priority proportional valve is not functioning, except in the minimum "fail- safe" mode. Refer to the Electrical section of this book for more information. Page 23 Hydraulic System Troubleshooting, Testing and Adjustment