SWING SPEED IS LOW SWING SPEED IS LOW 2) 2) 5-10 Does swing YES control valve YES spool move smoothly by hand? Is MCV pilot NO pressure same on LH and RH YES Clogged or oil sides? leak. Is not pilot piping Single direction clogged or is not NO it leaking oil? Is the trouble in one direction or NO in both direction? YES Does swing YES control valve Both directions spool move Is MCV pilot lightly by hand? YES pressure within NO Is dozer speed standard level? within standard value? NO NO Is swing motor's NO ⓐ drain rate within standard value? Check that pilot piping is not YES clogged or oil is NO not leaking from it? Clogged or oil Is gear pump pilot leak. ⓑ pressure within standard level?
YES Is gear pump NO delivering oil? NO NO Does the Is main relief YES symptom ⓒ valve setting YES change when LH pressure normal? and RH pilot hoses are Is safety valve exchanged? NO pilot pressure YES within standard YES level? Is gear pump output pressure NO within standard level? NO Cause Remedy Swing port relief valve is faulty. Disassemble and repair or replace. Disassemble and repair. Clean pilot piping interior or repair piping. Disassemble and repair. Disassemble and repair. Disassemble and repair. Disassemble and repair. Clean pilot piping interior or repair piping. Disassemble and repair or replace. Disassemble and repair. Main relief valve pressure resetting or repair.
Disassemble and repair. Repair or replace. Repair or replace. Repair or replace. Swing control valve spool is stuck. leak. Pilot valve or shuttle valve is faulty. ⓐ Swing control valve spool is stuck. ⓑ ⓒ Swing motor is broken. Pilot valve or shuttle valve is faulty. Pilot relief valve is defective. Gear pump is broken. Main relief valve faulty. Hydraulic pump is broken. Shuttle valve is faulty. Pilot relief valve is faulty. Gear pump is faulty. Check that pilot piping is not clogged or oil is not leaking from it? Clogged or oil leak. ogged or oil