Loc: mississippi, usa.
My 1936 truck seat is split so there are two lower seats and one back rest all the way across the back. Springs can be re-tensioned. On the lower cushion seat the corners have weaker springs than the main part so that part of the seat flexes as you get in and out. There are metal parts that project into the seat bucket. These hold the bottom seats in place. They do have some play and are not real tight fitting so they can be lifted out from the front for easy access into the storage area under the seats. Sometimes this projection breaks off. This can be solved with a bolt, two nuts and some washers (spacers). Place a nut on the bolt and adjust until the bolt hangs below the seat the proper distance. Remove place washer poke through hole and place washer then nut on top, tighten. They can be re-covered real easy. Small "C" clamps hook onto the rail on the bottom of the seat. (I am not talking about "Hog Rings".) Pressing the fabric into the rail holds it to the seat. Good luck on your seat problem. Note: the seat back is adjusted from the bottom. Push it forwards until desired distance. Block in place.
Loc: Hurst, TX , USA
1937 and 1938 truck seats are exactly the same as your 1936 truck. A seat rebuild may be necessary. I had mine rebuilt by a good local furniture builder and upholster. He tied the springs together, and wrapped the seat springs with poly ester (both of the sisters, Polly and Esther) and they are like new. Nothing wrong with the original seats after a treatment to the modern day upholster.