i am just re placing the three piece seat cushions on the 504 this old tractor is unrestored and clean as a pin no dings or dents diesel engine runs excellant i service this for a guy about every two years fix any little thing that it needs . but i agree with cihtech those air seats are a major pain in th2000s newer cabs when the air dosnot work for what ever reason just to get acces to any thing under thier