Start here--Base Removal (also required to measure a cylinder)
First turn the chair up-side-down so that the and in the center of the base bottom underside can be seen.
Spread newspapers on floor to prevent greasy falling parts from causing stains
If you are replacing a base with new supplied column, skip down below to Column Removal---All types
Abacus uncommonly includes a new column (AKA standpipe) with a new replacement base. We recommend you use this new column. This is especially important if your chair has a lot of milage on it, as the plastic part inside the the steel column near the top supporting the gas cylinder may be worn or perhaps cracked, loose or broken. All of which will cause your chair to annoyingly rock and wobble while in use. To remove the column which often appears that it does not remove, read this.
Virtually all columns in 5 star (leg) office chair gas bases are removable. When replacing a column in a gas office swivel base for replacement, the column diameter must be the same as the replacement. The diameter is measured midway at it's overall length (height). It will be either 1 3/4" (45mm) or 2" (50mm). No others are available.
With base and column in hand, squirt a shot or two of WD 40 at the at the topside of the Base and Column aiming where the Column and Base meet. Turn Base over and repeat at the underside of the Base and Column. The WD 40 must run down entering the tight fitting tapered joint to facilitate removal. Encourage this by sharply striking the side of the Column from 4 directions using a short length of 2" x 4" (14" to 18" will do very nicely) or a steel hammer. The idea is to "Shock" the Column setting up a vibration which will permit the WD 40 to run into the joint. Set the Base and Column aside for 5-10 minutes to permit the fluid to penetrate into the joint.
Then, with Base and Column underside facing you and using a steel hammer, strike out the protruding column with medium/hard blows. It may take several blows before it removes. Do not use a mallet! Nine out of ten columns can be removed in this manner...sooner or later. If you have a Ten, purchase a new Base with included Column.
It is highly recommended to replace the Style #108 Bearing Kit (each kit includes a schematic) whenever removing the base, column or gas cylinder. A #108 kit if ordered separately does not meet our required $20.00 minimum merchandise purchase.
The Column does not require any special installation into the Base. Simply inserting the Column into the tapered center base hole is adequate as the weight of the chair and normal sitting will seat the Column taper very tightly after only a single use or two. Do not use any tools to seat it tightly.