Other than taping over it with thick black masking tape, or using liquid leather which can be found in a hardware store, one can use a repair kit which can be purchased at a car repair or car parts store. In such a kit there must be a colorant which matches the colour of your leather seat but before the colorant is added, clean the leather with mild liquid facial or body soap, working it into a lather on a cloth and thus removing any dirt. Rinse the soap from the seat and then dry, then make the edges of the torn seat smooth if they are not already so, in order that the flat of the tear can be placed against the piece used to repair the seat. Place the backing cloth from the repair kit behind the tear by lifting an edge and sliding half of the backing beneath, doing the same to the other edge. Centre the canvas piece beneath the tear so that all edges lie on the backing piece. Following this, spread a thin layer of the adhesive from the repair kit onto the bottom edges of the tear with a palette knife, glueing the edges into place against the backing piece. Next, use the palette knife to spread the leather filler from the repair kit to the backing canvas between the torn edges, then build up the filler in layers until it slightly overlaps the leather seat, allowing each layer to dry. Sand the last filler layer until you achieve a smooth surface with the surrounding leather on the seat, then wipe away any residue and apply the colorant with a cloth, allowing it to dry.
