Unit : mm / 5 min 7-13 10)DIG FUNCTION DRIFT CHECK (1) Measure dig function drift, which can be caused by oil leakage in the control valve and boom, standard arm, and standard bucket cylinders, with the loaded bucket. When testing the dig function drift just after cylinder replacement, slowly operate each cylinder to its stroke end to purge air. (2) Preparation ① Load bucket fully. Instead of loading the bucket, weight (W) of the following specification can be used. ·W=M3×1.5 Where : M3 =Bucket heaped capacity (m3) 1.5=Soil specific gravity ② Position the arm cylinder with the rod 20 to 30 mm extended from the fully retracted position.
③ Position the bucket cylinder with the rod 20 to 30 mm retracted from the fully extended position. ④ With the arm rolled out and bucket rolled in, hold the bucket so that the height of the bucket pin is the same as the boom foot pin. ⑤ Keep the hydraulic oil temperature at 50±5˚C. (3) Measurement ① Stop the engine. ② Five minutes after the engine has been stopped, measure the changes in the positions of the boom, arm and bucket cylinders. ③ Repeat step ② three times and calculate the average values. (4) The measured drift should be within the fol lowing specifications. Model R505LVS Drift to be measured Boom cylinder Arm cylinder Bucket cylinder Standard 10 below 10 below 40 below Remarks