How to repair a zipper on a pair of pants using ZlideOn
A fly that won't stay up, or won't close at all, is almost always down to a worn slider rather than a ruined pair of trousers. Swapping it takes a couple of minutes at home — no unpicking the waistband, no sewing, no tailor.
Get the right ZlideOn for your pants
First things first! Check the number printed on the back of your old slider, or measure the width of the zipper teeth, and pick the ZlideOn that matches. Trouser flies are usually small — size 3 covers most chinos, suit trousers, and workwear.
Recommended product for pants
Carefully snap off the broken slider
Grip the old slider with a pair of pliers and snap it off the top of the fly, above the stopper. Trouser flies sit in a narrow channel, so fold the fabric flat first to give yourself room to work.
Fully open your ZlideOn
Hold the ZlideOn between your fingers and open it up completely, so the two halves are ready to sit around the zipper chain.
Click it onto the zipper
Place the open ZlideOn over the zipper teeth and press both sides firmly together until you hear it click shut. Run it up and down the fly a few times to bed the teeth in — your pants are repaired.
Better to see it in action?
The whole repair takes less than a minute. Watch it done from start to finish.
Watch the ZlideOn repair video
Important things to remember
ZlideOn replaces the slider — not the zipper chain itself. Before you start, check the teeth and the tape stitched into the fly: if teeth are missing or the tape has pulled loose, the fly needs restitching rather than a new slider. Far more often the slider has simply worn wide, which is exactly why a fly starts creeping down on its own.
Getting the size right matters. Check the number printed on the back of your old slider or measure the width of the zipper teeth before ordering. Trouser flies are typically size 3 in metal or plastic, noticeably smaller than the zippers on jackets. If you're unsure, a multipack covers the most common sizes and is the safe choice.
A trouser fly is a closed-end zipper, so the ZlideOn goes on from the top, past the stopper at the waistband. If the zipper skips or won't hold after the first few pulls, don't force it: open the slider, check that both rows of teeth are seated fully inside, and press it shut again.
Why repair your pants instead of buying a new pair?
Trousers that fit properly are hard to find and easy to lose to one broken part. Replacing the slider with ZlideOn takes minutes, costs a fraction of a new pair or a tailor's bill, and needs no sewing or specialist tools. Made in Europe from durable zinc and steel, a ZlideOn slider will outlast the fabric around it.
Repair, don't replace. Every garment kept in service saves the CO₂, water, and raw materials that go into producing a new one. Choosing to repair is one of the simplest, most effective sustainable choices you can make — and with ZlideOn, it's also one of the easiest.