1. Use a stitch remover to remove the suture at the end of the zipper, and both sides must be removed. No need to dismantle too much. The purpose of stitching is to expose the metal tabs at the end of the zipper and the structure of the end. Don't think about removing the entire zipper. Remove the metal composite. You can use needle-nose pliers to open and remove the metal hinge. Be careful not to remove too much thread or accidentally damage the zipper.  

2. Take off the slider on the zipper. Remove the slider on the zipper from the zipper. If you can’t remove it, you can open it with pliers. But this is likely to damage the teeth or the zipper, so pull it down as much as possible.  

3. Install the new slider carefully. Before pulling up the slider, first let the zipper enter the upper opening of the slider, and then let it pass under the slider.  

4. If you have a small problem when installing the slider, try a pin or sewing needle, and carefully pull the zipper into the slider. Make sure the teeth in the slider are snapped together.  

5. Pull up the slider until there are closed teeth at the end.  

6. Sew out a composite sheet. Sew at least six stitches at the bottom of the zipper. Be sure to sew under the slider, a new hinge is formed.  

7. The metal hinge cannot be put back after it is removed, but a few stitches can replace the hinge. Sew on the zipper again. Sew back the zipper as it was removed. This step is over. The zipper is now safe, and the slider can move back and forth smoothly.