Any leather furniture is an investment due to its cost. When a leather sofa has a tear in a seam, the price to fix it can cost almost as much as you paid for the sofa. For those who have any sewing skills, this is something that you can fix yourself. All you need to make a proper repair job on the seam of a leather sofa are the proper tools.
Use a curved needle when stitching the seam on a leather sofa. Curved needles are commonly used in upholstery work where it is difficult to pull out a straight needle, such as along the corners of chairs. A curved needle will automatically face upward as you are pushing it through the seam, which makes the job of pulling it out completely much easier.
Keep some pliers nearby when sewing a seam on a leather sofa or when you are doing any other type of upholstery. It can sometimes be difficult to pull the needle fully out of the fabric. The pliers give you something that can grip the needle better than your fingers. It also gives you a little leverage that also makes it easier to pull out the needle. Be careful that you do not pull too hard so that the thread comes out of the needle each time you pull or that you pull so hard that you tear the leather.
Sew the seam on the leather sofa using a nylon or a waxed thread. These threads are much stronger than a polyester or a cotton thread. Seams in sofas take a lot of stress, hence the reason you have to fix the seam in the first place. Using a stronger thread will hold the seam together better and the thread will not deteriorate as quickly. Double up the thread by inserting one end through the needle, meeting up the ends and knotting them together. This makes the thread that much stronger.
Use an awl only if the original holes in the seam are damaged and no longer usable. It may be a little difficult to use, but it is possible. Insert a small piece of wood where the seam is torn and use the awl to punch new holes. You may be able to simply push the awl through the leather of the sofa or you may need to use a rubber mallet to use a little more force. Either way, make sure you have some form of support behind the awl so it will not punch holes in an undamaged section of the sofa.