How do I replace the gas cylinder on an office chair?

Turn the chair upside down. Use a rubber mallet to knock the base off the cylinder (the taper releases after a few firm strikes). Pull the cylinder from the mechanism with a pipe and mallet. Insert the new cylinder into the mechanism first (it clicks in), then seat the base on the lower end. Test by sitting on the chair — the cylinder is seated correctly if the height holds. Replacement cylinders must match the original's extended length (typically 6"–10"); most standard cylinders have a universal 22mm diameter stem. FindOfficeFurniture.com sells chairs with easy-to-replace cylinders — call 888-719-4960.