Manual Lumbar Support Driver's Seat

[cg82]

I have a 99 Exlporer Eddie Bauer and the lumbar support (manual not electric) has recently stopped working on the driver's side. When I inspected the knob it fell off and a black plastice cylider that is threaded on one end and had two plastic 'fingers' on the other (one appears to be broken off) came out. I can reinsert these and the knob seems to have some tension when I twist in the direction to deflate the seat. However, the seat is already deflated and will not inlfate or deflate. When I compared it to the passenger side it appeare that there is another white plastic cylinder missing. Has anybody repaired one of these before? If so do you have any tips? Also other then a scrap yard where might I buy these parts as I doubt I can order them from a dealership now. Are there any commercially available repair kits?

Thanks