How to replace a Gas Lift or 5-star base (follow steps 1-3 &9-11 for base replacement)
Gas lifts fit to chairs by using a friction fit which has to be released to remove the gas lift.
Tools required: A big hammer/lump hammer, release agent, possibly a drift to enable better access, possibly a flat/pozi drive screwdriver.
1. Turn chair upside down onto some support ensuring the back/headrest is clear of the ground and the chair is stable (NOTE: Get help if required). Another chair without arms is ideal – extend to full height first.
2. It is recommended at this point to apply release/penetrating agent (i.e.WD40) to both meeting points of the gas lift to the chair – where it meets 5-star base and the seat base.
3. Supporting the weight of the chair by holding the 5-star base hit the base of the gas lift until it separates from the 5-star base (NOTE: Castors may fall out whilst doing this if not already removed). A drift may be required if the gas lift does not protrude from the centre of the 5-star base and may require another person to hold /support the 5-star base. If only replacing the base take care to not damage the gas lift.
4. Some chairs have plastic covers where the gas lift meets the seat unit, if present they are usually just retained in position by a few screws – remove any covers.
5. Supporting the weight of the chair by holding the gas lift and using a hammer with drift if necessary, taking care not to damage the chair/mechanism, hit the seat base mechanism as close to the gas lifts piston as possible until the gas lifts piston is released from the friction fit. (NOTE: If used over a long period of time the fit could be very tight and need a bit of hammering to release).
6. Remove the gas lift concertina cover and fit to the new gas lift.
7. Place the gas lift piston with cover in place into the hole in the seat mechanism.
8. Replace any covers removed in step 4.
9. Place 5-star base onto the body of the gas lift.
10. Replace any castors that have been separated from the base.
11. Holding the chair by the arms or back support column and the 5-star base return the chair to normal position (NOTE: Take care when turning the chair back over that the base/gas lift do not separate from the chair).
Disclaimer: These instructions are a guideline only and should be followed with care for personal safety and the safety of others around. Be careful when lifting/carrying chairs to avoid injury, get help if required. The Chair Clinic Ltd accept no responsibility or liability for any injuries and/or damage incurred from following these instructions, you follow these instructions at your own risk.
NOTE: Some office chairs use a cable operated gas lift which will require non-standard replacement gas lifts and a more intricate replacement procedure which we recommend to be done by our experienced engineers.