Before you can fix the seam, you need to remove the seat so you can take off and repair the cover.
Most seats are held in with pressure clips, but there may be bolts you have to unscrew to remove the seat. Remove the cushion first and then you’ll be able to take off the backrest (if needed).
You may have to remove the seat belts and go to the trunk to pop the latches open to release the backrests. Once you figure out where the latch is, all you need is a screwdriver to pop it loose. Make sure to get all the latches, then pull the seat forward and remove it.
Now, remove the covers from the seats. These steps may vary, but with most, you can use a flat-head screwdriver to pop out the arrow clips that may be sewn onto your cover. There may also be staples you need to remove in a few places. All of this will go back together perfectly once you have repaired your seam. You may also find hog rings as you go to lift up the cover. These help to hold the bolstering in place and give it a nice look. Simply use wire cutters to snip these rings so you can fully remove the cover.
The cushions and backrest will have similar steps for removing the cover. Just take your time and pay attention. You may struggle with removing the headrests, so you may have to open the back of the seat first and undue some bolts. If your seat has a built-in armrest in the center, you’ll also need to unbolt it to fully remove the cover.
Method #1: Without A Machine
You can fix a ripped seam by hand with basic supplies, even if you don’t have a sewing machine.
What you need is a curved needle and a sewing machine needle (size 17). You’ll want thread that matches your current thread, I used size 92, bonded polyester. You’ll also need scissors and needle nose pliers.
Take a long section of thread of about 2-3 feet and then put it through the curved hook. When you have it through the eye of the needle, tie it off to secure it. Turn your cover inside out and figure out where the seam has opened up.
You’ll want to start further back in an area where it’s still sewn together. You need to use the existing holes already in the cover to ensure the finish look appears professional and original. It can be difficult to find a hole, but look carefully.
Poke your curved needle through an existing hole. You can use the needle nose pliers to help push/pull it through the hole.
Pull your thread about half way through, and then find the hole directly backwards from where you just sewed.
Push your curved needle back through the top side in that next hole.
When you’re back through the top, go back through the hole that you started on. This will allow you to pull the thread tight and lock it so it doesn’t pull out later on. While you’re pulling the needle through, you can spread the seam apart a bit to make sure it is piercing through an existing hole on both the top and bottom pieces of fabric.
Pull your thread tight to cinch the pieces together.
Now, take the thread that’s remaining on the top side of the fabric and run it through the eye of your machine sewing needle. Don’t tie it off, just run it through.
Use the top needle and push it through all of the existing holes.
Once you push your machine needle down, use your hook with the thread of the other side through the loop you get as the other needle comes down.
You’re going to repeat this process to get a seam that matches your factory seam. Again, use your machine needle to come down, pull it back a little bit to get a loop, and then run your hook through it.
Pull the thread tight and then pull the machine needle up the rest of the way, and repeat for the next hole.
When you get to the end of the repair you will want to stitch backwards one stitch. Then remove the curved needle and pull both threads to the top. Now you can tie an knot to lock the stitch in place
Method #2: Using A Machine
When using a machine, sew the seam allowance up a bit tighter to make sure you don’t have any existing holes showing.
Sew a bit past where the seam ripped and then do a lock stitch on top of the old seam to lock in the new and old stitch so neither come apart. Be sure you aren’t sewing any wrinkles into the piece, take your time and do it evenly.
When you’re done, fold the seam open and see if even adjustments are needed. You might notice you didn’t sew it tight enough in one area and the old holes may be showing. If that’s the case, simple fold it and go over the area again.
You shouldn’t see any old holes when your finished.
These are two rather simple ways you can repair a broken seam in your car without having that much experience. Just take your time and go slow, and you can get a factory finished seam in no time.