Rebuilding the lift mechanism
If the lift mechanism in your office chair needs repair but the upholstery portion is still in good shape, don’t toss the chair. Fix it! You can replace the gas cylinder yourself for about $40 (one source for office chair parts is swivel-chair-parts.com).
Rebuilding the lift mechanism is a two-part process. First you have to disassemble the lift mechanism so you can measure the size of the gas cylinder and order the new part. You’ll need a needlenose pliers, a pipe wrench with a long handle, and a helper. Disassembly takes about a half hour. Then you just reassemble when the part arrives. That only takes 15 minutes, and you can do it without a helper.
Start the repair by flipping it upside down on your workbench. Then remove the spring retaining clip on the bottom of the pedestal (Photo 1). Next, lift the entire pedestal and column off the chair. Lift off the bearing, washers and rubber bumper and keep the parts together for reuse. Remove the telescoping trim bezel (Photo 2).
Then grab your pipe wrench and helper and remove the cylinder (Photo 3). If it won’t budge, soak it with rust penetrant and tap with a hammer to set up vibrations. Then try the wrench again.
Measure the length of the gas cylinder from the bottom of the taper to the top. Don’t include the piston rod in the measurement. Then measure the cylinder width at the widest part. Order the replacement from an office chair repair parts Web site.
To reassemble, just push the tapered end of the cylinder into the chair seat and install the telescoping trim bezel. Slide on the rubber bumper. Then lubricate the bearing with grease and install it back on the piston rod with the original washers. Next, slide the pedestal base and column over the rod and secure the piston rod with the washer and spring clip. Finish the job by turning the chair right side up and bouncing on it a few times. Your weight will drive the tapered gas cylinder into the seat retainer. Then raise the lift mechanism to the proper height and get back to work.Online sources for parts:
Replace a caster
When casters roll around long enough in dust, dirt and hair, they stop rolling and start skidding. And that’s how your floors get scratched up or your carpet gets wear tracks. Sometimes you can bring casters back from the dead by cleaning and lubricating them. So try that first. Just spray household degreaser/cleaner right onto the roller axles. Then spin the wheels to loosen them up. If that helps, rinse off the cleaner, blow them dry with compressed air, and then lubricate them. If cleaning doesn’t help, you’ll have to replace them. Here’s how.
Most office chairs use a twin-wheel grip-ring style caster. The grip ring compresses and snaps into a groove in the socket. The easiest way to remove a grip-ring caster is with a flat bar (Photo 1). Before you buy replacements, measure the width and height of the stem. The most common widths are 3/8 in. and 7/16 in. There’s only a 1/16-in. difference between the two, so measure carefully! If you try to fit a 7/16-in. stem into a 3/8-in. socket, you’ll crack the socket.
Next, measure the wheel diameter. If you want the chair to push back easier or roll over small items on the floor rather than get stuck, buy a caster with a larger wheel. Buy a urethane tread caster for wood (and composite), tile or vinyl floors. But if the chair will roll on carpet, buy a hard rubber or nylon tread caster.
To install the caster, tilt it into the socket to compress the grip ring (Photo 2). If you can’t get it started, apply a drop of oil to the ring. If the caster only goes in halfway, tap it with a mallet (Photo 3).