Abstract: A height adjustment system for a seat assembly of a machine includes a first support member and a second support member vertically spaced from the first support member. A pneumatic bladder is operatively connected to the first support member and the second support member for adjusting a distance between the first support member and the second support member. At least two guide pins interconnect the first support member and the second support member at opposing ends thereof. A locking device maintains an adjusted distance between the first support member and the second support member. The height adjustment system is preferably independent from and may be positioned in series with a suspension system for the seat assembly.