ANCHEER SPORT via YouTube
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1. Unscrew the screw of the hub axle (on the side where the brake is located), and take out it;
2. You can see the balls inside. Taken them out, coated the ball plate with lubricating oil, and then the put balls back in order;
3. Take the replacement axle and replace the old one, tighten the screws to ensure that they are tight, and check whether the front wheel can rotate smoothly. If so, that is done.