Yes I'm sure it can be replaced. The Phone number for technical support and Parts is 800-999-8899 it's called the air shock for the Power House WM 1400
Meijer seems to have the manual--same model number as at Amazon, for example.
http://www.meijer.com/assets/product_files/pdf/Gym_Dandy_Impex_Space_Dome_Manual.pdf