Disaster struck last week when the zip in my favourite pair (read: I live in them) of jeans split. To be fair, these jeans are about 8 years old and they’re doing pretty well. They’re distressing brilliantly and have an awesome skull-patterned patch on the knee cut from a favourite old tote. I’ve worn these jeans everywhere and I was probably wearing them when I met my husband. I don’t remember. In any case, I was so not ready to let them go.



So I thought I’d share the process of changing the zip with you, so you can save your own favourite pair of jeans when the day comes. It can be a bit tricky to get your head around, so I’ve included a LOT of pictures. And a lot of words too.

Obviously I’m replacing a zip in a pair of women’s jeans here; the fly on men’s jeans is mirrored, so bear that in mind if that’s what you’re working on.

First things first: you will NEED:


Ready to go

  • to put a needle in your machine that’s suitable for denim. Most companies will put “Jeans” or “Denim” on the packet. A sturdy needle is essential for sewing heavy fabrics.
  • sturdy thread. Buy good quality – some brands produce threads especially for denim repair, otherwise look for quilting or upholstery threads. If your thread snaps a lot as the needle passes through the fabric, you need stronger thread.
  • a new jean zip. Measure the broken zip – if you can’t get a new zip in the exact same size, get one slightly larger.
  • a seam ripper and/or scalpel.

An optional tool is a gadget that I only know as a “jean-a-ma-jig” – a web search will come up with plently of places you can buy one. My machine came with something similar that’s listed in the manual as “multi-purpose tool”. I’m not sure how I got by without it before. You could probably use thick card with a notch cut out as a substitute. It sits under the front or back of the presser foot to help ease it over bulky seams, and I used it here when top stitching the waistband ends.

Right. Go time!

replacing the zip in jeans fly

The inside of the jeans after the zip has been removed

1. Unpicking the old zip is the first step. (Note: if there is a metal rivet at the bottom of your fly, you may want to find a different pair of jeans to practice on. It is possible to replace the zip if this is the case, but you have to compromise and it makes things very awkward. Make a mental note never to buy from such a short sighted brand again.)

You want to remove maybe 2″ of stitching from the lower waistband ends, without unpicking right to the end. It’s better if the placket (the piece I’m holding in the above picture) and fly facing (the opposite side) are still attached by a stitch or two. Any stitching that’s holding the zip in obviously has to go, and the (typically) two curved rows of topstitcing to release the fly facing.

I like to use a seam ripper for most of this, then carefully cutting through bar tacks (the really tight zig-zag bits that make you want to say bad words) with a scalpel. Just mind the fabric — and your fingers.

replacing the fly zip in jeans

Pinning the zip onto the fly facing

2. Now you’ll want to pin the zip onto the facing. Working from the inside as pictured above, place the zip face down, aligning the edge of the zip with the edge of the fly, and tucking the bottom of the zip as far down as it will go without bunching. There are other ways to align the bottom of the zip, but I prefer to allow a bit of space at the bottom after the teeth end so that I don’t risk losing the runner of the zip in the bottom of the fly. ‘Cause then it’s a bugger to get back out.

Now sew one or two rows of stitch down the left side of the zip, through the facing only and not through the front of the jeans – so you’re only sewing one, inner layer of denim. You may need to wiggle the waistband upwards to avoid sewing through it accendentally. Also, looking at the picture above, note you are sewing the opposite side of the zip to your pins, the side furthest from the folded ouside edge.

replacing the fly zip in jeans

Securing the zip to the facing


Make sure you’ve sewn the right side of your zip, and that you’ve sewn it face down


Trim the left side of the zip

3. Trim the side of the zip that you’ve just sewn so that it matches – or is very slightly over – the top edge of the facing. I like to leave a little extra, check I’ve done everything right, then trim the excess before sewing any further. Be careful at this point not to try and close the zipper fully – you can easily pull the runner off, and they can be tricky to put back on.


Tuck the facing & zip back into the waistband

4. Tuck the facing and now-attached top of the zip back into the waistband. Check that nothing is folded or bunched (if you’ve left your zip too long, it may bunch up against the buttonhole from the inside). Try to align everything as it was originally.

replace the topstitching jean fly

Replace the top stitching – pull the waistband out of the way again

5. Starting with the double row of curved stitching, replace your top stitching, working from the outside of the jeans (pin or tack the inside facing down if you’re worried it won’t stay in place as you sew). Start as close to the raw edge under the waistband as you can, and back-tack the end of each row at the bottom of the fly. As you sew the bottom, pin or fold the end of the opposite half of the zip out of the way as shown below. You do not want to sew that half of the zip at all yet.


Fold the unsewn end up out of the way


The inside after topstitching. Notice one side of the zip has been caught by the top stitching, the other is still free


The outside after top stitching. It is usually pretty clear where the old stitching was. Some of the old thread is still visible here


My “jean-a-ma-jig” in use

6. The next step is to sew the waistband, on the side you’ve been working on, closed again. Top stitch from the outside of your jeans, using your jean-a-ma-jig to keep the presser foot level. Continue sewing until you’ve overlapped the existing stitches slightly to secure.


Trim the other side of the zip

7. With one half of the zip now complete, trim the other side of the zip so it’s level with the bottom of the buttonhole. Button up your jeans and, with the zip closed as far as possible, tuck the loose zip end into the waistband as you did before.



Buttoning up your jeans will help you to align the second half of the zip accurately


How this looks from the inside

8. Next, align the overlocked adge of the placket, the edge of the zipper, and the edge of the fold and pin.


Align the three edges. Note that, like before, you are not sewing through the front of your jeans


Sew the placket (top layer), zip (middle) and folded facing (bottom) as one

9. Unfold that bottom layer to get your little sandwich under your machine foot, and sew from as close to the top as you can, to as far down as you can.


Pin the fold in place, ready to top stitch

10. Now working from the outside, pin the folded edge and top stitch it to your zip, again wiggling the waistband out of your way, sewing down as far as you can.


Top stitching the waistband

11. Now it’s time to tuck everything on this side into the waistband and top stitch.


I won’t be able to get my finger under there when I’m done!

12. You’re nearly there now: topstitch the bottom of the fly on the centre seam – where my finger is tucked under in the picture above. There will already be stitching around here, you just want to make sure this bit is sewn through all layers.


Pinch the placket and the edge of the facing

13. Pinch the edge of the fly facing and the placket together as shown above, and sew a few stitches back & forth to secure them together (make sure the placket is lying nice and flat when you’re done).


Sewing the edge of the facing to the placket


The completed zip replacement

And there you have it! Your jeans are saved! Hooray!

How did you get on? Let me know how you get on in the comments :)