A separating zipper refers to the sides of metal teeth coming apart when you pull the slider. Separating zippers seem to occur at the worst possible time, when you're rushing out the door or late for an appointment. Luckily, you don't have to hand over the article of clothing to a professional seamstress or garment repair person. While repairing a zipper may look intimidating, especially if the zipper has separated, it's actually pretty straightforward to fix.
Place a pair of needle nose pliers around the bottom of the zipper and yank off the metal stoppers.
Guide the slider down to the bottom of the two sides of teeth, being careful not to take it off completely. As you move the slider downwards, correct any twists or creases until you get to the bottom.
Realign the pairs of teeth one by one as you slowly pull the slider back up. The slider should now be able to interlock the teeth perfectly.
Turn the article of clothing inside out. Thread a needle with sturdy nylon thread. Sew a new stop at the bottom of the zipper to replace the metal stoppers that you removed. Make eight or nine tight stitches at the bottom of the zipper, which will act as new stop. Double knot your thread when finished and cut off the excess.