When the excavator was turning under heavy load, it made irregular creaking noises. It is necessary to use a sound wave detector to check whether the outer diameter of the slewing motor, the housing of the slewing reducer, and the outer diameter of the slewing ring is abnormal. The position where the sound is louder is the slewing ring gear. Install a pressure gauge on the main pump. When the excavator rotates under a heavy load, the gauge needle swings, but whenever a sound is made, the pressure value drops immediately.

Park the excavator in an open area, straighten the boom and stick, and the bucket is about 1m away from the ground, the engine is turned off, and the residual pressure is removed. When the slewing ring is not disassembled, remove the fixing bolts on the slewing ring and pull out the motor from the reducer, so that the motor main shaft is separated from the gear sleeve of the rotary reducer for a short distance and then fixed. Start the engine and manipulate the motor to make a slewing action. Because the slewing motor has been separated from the slewing reducer, when the motor is idling forward and backward, it runs smoothly and there is no abnormal noise. It is proved that the slewing motor is faultless, and the motor can be separated from the excavator.

Use manpower to push the bucket to make the excavator turn left and right, and the person on the machine judges whether the abnormal noise is emitted from the slewing reducer or the position of the slewing ring gear. If there are abnormal noises at the two positions, the reducer needs to be removed from the excavator to check whether the spindle end bearing is damaged.

When the bucket is pushed by manpower, there is still abnormal noise in the rotary gear ring of the excavator. Remove the slewing ring gear and observe whether the flame layer on the rolling surface of the roller is peeled off.

Send the slewing ring gear to the repair shop. After grinding the raceway according to the enlarged ball size, re-fire. After the repaired slewing ring gear is installed on the excavator, the operation can be started.