Replacing a snap on a jacket takes just a few steps. On a jacket, snaps come in all different shapes and sizes, and tend to pop off with use. Once this happens, you will have to replace the entire snap, including the button, the stud, the socket and the ring. You can purchase a snap repair kit at any local fabric store or online.
Wedge a flat-head screwdriver under the broken snap and carefully pry if off of the jacket. Be careful not to rip the fabric. Needle-nose pliers might be necessary, depending on the type of snap.
Insert the snaps into the snap tool per the snap kit's instructions. Usually this is done with the socket and the snap in the middle and the brad on the end, although different types may vary. Since these are larger-sized snaps, there will be several different parts. The brads are small metallic spikes that attach to the fabric, rather than going through the fabric like with a button.
Insert the clasp into the snap tool per the snap kit's instructions. This step will be much like the previous, only using different parts. This side of the device gives the snap something to snap into and hold.
Tap several times with the end of the screwdriver so that the metal snap is tight on the jacket fabric.
Repeat Steps 3 and 4 for the closure.
Read the instructions and follow the simple diagrams for inserting each side of the snap, as well as the pieces of the snap.