BOOM, ARM OR BUCKET POWER IS WEAK BOOM, ARM OR BUCKET POWER IS WEAK 4) 4) ONLY BUCKET OPERATION IS TOTALLY IMPOSSIBLE ONLY BUCKET OPERATION IS TOTALLY IMPOSSIBLE 5) 5) 5-20 YES Is cylinder YES internal leakage within standard level? Is relief pressure YES in port relief valve within NO standard level? Is relief pressure in main relief valve within NO standard level? NO Cause Remedy Cylinder is faulty. Port relief valve is faulty. Main relief valve is defective. Check according to the procedure in Item "Speed is low". Disassemble and repair. Adjust pressure, repair or replace. Adjust pressure, repair or replace.
YES Does the symptom change YES when port relief YES valve is replaced Does control with other valve? valve spool Is MCV pilot NO move smoothly pressure within by hand? standard level? NO NO Cause Remedy Port relief valve is defective. Cylinder interior is broken. Control valve spool is stuck. Pilot valve is faulty. Disassemble and repair or replace. Disassemble and repair. Disassemble and repair. Disassemble and repair.