How to Install Foam to Improve 2010 Prius Seatback Comfort

There is another thread in this forum in which I provided instructions on how to install foam between the springs and the underside of the seatback pad. However, that method is not always successful. This new thread provides a different and better solution to make the 2010 Prius driver’s seatback comfortable.

The previously installed seatback foam between the springs and the underside of the seatback pad was starting to wear out causing me some discomfort. I removed that old foam and then disassembled the seatback so I could pull up the seatback cover and expose the topside of the seatback pad. This allowed me to install one inch medium density foam between the existing hard seatback pad and the seat cover. Now I feel the much softer and more comfortable foam, instead of the hard seatback pad, against my back. WOW, what a huge improvement.

Below are instructions for removing the driver’s seat and inserting foam between the existing hard seatback pad and the seat cover.

Prius Driver’s Seat Removal:

1. If you feel safer working on a seat with airbags, disconnect the negative terminal from the 12V battery in the rear hatch area. Personally, I have removed car seats with airbags from several cars numerous times and don’t do this because the airbags cannot be exploded by jostling or removing the seat.
   
   
2. Press in the headrest adjustment button and pull up to remove the headrest. Removing the headrest will make it easier to get the seat out of the car.
   
   
3. Lift the bar under the front of the seat and move the seat to its foremost position.
   
   
4. Remove the two trim caps that cover the seat-to-floor mounting bolts on the rear of the left and right seat tracks.
   
   
5. Remove the two rear seat-to-floor mounting bolts with a ratchet wrench and 14mm socket.
   
   
6. Lift the bar under the front of the seat and move the seat to its rearmost position.
   
   
7. Remove the two front seat-to-floor mounting bolts.
   
   
8. Lift the bar under the front of the seat and move the seat to the center position.
   
   
9. Operate the reclining adjuster release handle and move the seatback to the full upright position.
   
   
10. Tilt the seat back to gain access to the underside of the seat.
    
    
11. Disconnect the electrical connectors under the seat.
    
    
12. Lift the seat, rotate it to the left and remove it from the car through the driver’s door opening.
    

Open the Seatback Cover:

1. Place the seat upside down on top of a piece of carpeting or cardboard to protect the fabric or leather.
   
   
2. Unhook the rear seat cover flap on the underside of the seat.
   
   
3. Remove the three hog rings at the base of the seatback. Two needle-nose pliers work good for opening the hog rings.
   
   
4. Unzip the two zippers at the base of the seatback.
   
   
5. If your seats are heated, disconnect the seatback heater wire holder and connecter.
   
   
6. Disconnect the three hog rings that anchor the two plastic cords that run up through the seatback cover.
   
   
7. Pull the seatback cover up to expose the embedded horizontal curved wire about two thirds up the seatback.
   
   
8. Remove the three hog rings that secure the wire mentioned in step 7.
   
   
9. Pull the seatback cover up as far as it will go.
   
   
10. If the seatback pad curvature in the lumbar area is too prominent, as it is for me, you can cut it down as shown in the below picture. This allows for a flatter seatback. I have power lumbar support in my seat so it is not a problem if need to adjust.

11. Cut two pieces of foam per the below drawing.




12. Install the foam as show in the below picture.




13. Reverse these instructions to close up the seat and reinstall it in the car.