Return to Master Table of Contents BUCKET OPERATING CIRCUIT The bucket operating circuit includes the right and left main pumps, the both sides of the control valve and the bucket cylinder. 360 kg/cm (5,112 psi) overload relief valves located at crowd and dump cylinder ports on BUCKET of the control valve protect the circuit and its components from damage. 2 BUCKET CROWD CIRCUIT When the bucket control lever is placed in the crowd position, the right side pilot valve generates secondary bucket crowd pilot pressure that is transmitted to BUCKET and BC spool of the control valve.
When secondary pilot pressure reaches 7 - 10 kg/cm BUCKET CYLINDER (100 - 142 psi), the BUCKET and BC spools open so that oil from both pumps goes to the bucket cylinder. 2 PUMP(L) PUMP(R) ATS0790L Figure 6 BUCKET DUMP CIRCUIT When the bucket control lever is put in the dump mode, the right side pilot valve generates secondary bucket dump pilot pressure that is transmitted to BUCKET spool of the control valve. When secondary pilot pressure reaches 7 - 10 kg/cm BUCKET CYLINDER (100 - 142 psi), the bucket spool opens so that oil form PUMP(L) goes to the bucket cylinder.
2 PUMP(L) PUMP(R) ATS0800L SWING OPERATING CIRCUIT Figure 7 The swing operating circuit consists of the right main pump in the pump assembly, the right half of the control valve and the swing motor. To keep the upper works from coasting when the swing control is in neutral, an electrical sensor in the control circuit activates a valve to automatically engage a mechanical brake. Page 8 Hydraulic System Troubleshooting, Testing and Adjustment BUCKET CROWD PILOT BUCKET BC BUCKET BUCKET DUMP PILOT