One common failure I’ve seen on a lot of E28 M5s and E28s with sport seats is that the driver’s side bolster sags. This is usually caused when the bottom side bolster seat frame becomes separate from the base at the front of the seat. This car had the same problem when it was delivered (first photo), so when the seats were out after I detailed the interior, I took the driver’s seat to a local upholstery shop for repair. The shop welded the seat frame and also re-stuffed the seats. I wanted to address the broken piping, but it wasn’t clear that they could make it exactly original and it also sounded very involved to undo it.
Each seat had missing or broken parts on the inside hinge covers, so I ordered parts to replace the sliders and screws.
After I got the driver’s seat back, I went about addressing the faded leather. I used a product called Doc Bailey’s Leather Black, which is a conditioner with a black dye in it. It worked really well to bring back the color, shine and luster to the seats. I was very pleased with the results and was happy to put everything finally back into the car.