To fix a leather car seat, the general process involves several careful steps to clean, repair, fill, and restore the leather surface:

1. Clean the leather seat thoroughly to remove grease, oils, dirt, and previous treatments. This preparation ensures better adhesion of repair materials.
2. Trim any loose or sticking out leather edges around the hole or tear for a smooth repair surface.
3. Apply a backing patch under the tear or hole inside the seat to provide a firm base for the repair.
4. Use a flexible leather filler or heavy filler, applied in several thin layers, to build up and fill the hole or crack, smoothing each layer before drying.
5. Once the filler is level with the surrounding leather, clean the area again and let it dry fully.
6. Optionally, use leather dye or colorant to match the repaired area with the rest of the seat.
7. Finish by applying a leather conditioner or polish to restore the seat’s softness and shine.

This method can handle holes, tears, and cracks in leather car seats and can be done with a leather repair kit or separate supplies like leather glue, filler, patches, and cleaners. Patience and precision are key to a less noticeable and durable repair.