[72 Money Pit]

LMC Truck (lmctruck.com 800-LMC-TRUCK) carries a lot of repair and rebuild parts for seats. They have got a lot of my money. There are two designs, but it sounds like yours is the same as mine...a spring base with a foam-covered spring cushion. Look underneath the seat for individual springs that are deformed or broken. Replacements springs are $3-4.00 each. You still have to replace that foam-covered spring, but you can purchase some really dense foam from an upholstery supply place. The other style is just a solid foam cushion for which they want more than 2 c-notes. There are other places besides LMC, but whoever you go to, it is worth getting a hard copy catalog. The illustrations and breakdowns of detail parts are very helpful, and you can get quite a bit through them.