This can happen both after many years of daily use, and a couple of months after purchasing the chair.
The life of a chair is influenced by many indicators, including how well it was treated. Load capacity also matters – most models are rated for maximum permissible weight up to 300 lbs.
So that you won’t be surprised by the unpleasant consequences, it is necessary to know the causes and consequences of the breakdown.
Gas lift technology
A special mechanism is responsible for raising and lowering the chair – a gas lift. It is installed on the construction frame, directly under the seat of the chair.
Gas lift performs the following functions:
- Amortization. The gas lift absorbs the shock load when you sit abruptly in a chair. This creates a pleasant, shock-absorbing effect when sitting.
- Descent and ascent. Thanks to a special mechanism, the chair lowers and rises by itself, which allows to fully adjust the height for people of different heights and constitutions.
- 360-degree rotation, allows the seat to rotate freely in both directions.
Making the conclusion: if the chair sinks under the weight, then the problem lies precisely in the breakdown of the gas lift.
The principle of operation is simple: a gas lift is a sealed cylinder with two chambers with gas inside. When interacting with the lever, the partition between the chambers opens and the gas passes from one chamber to another. When the lever is released, the baffle closes, which forces the mechanism to lock in the selected position.
Reason why the chair does not hold height
So, let’s clarify the possible reason why the chair does not hold height:
- When you sit in the chair “on the fly.” Abrupt sitting creates an overload inside the gas lift mechanism. In one of the next “falls”, the valve will simply be squeezed out, and the system will fail.
- Wear of the elements of the mechanism. Sometimes the height of the chair does not hold, because the casing of the gas cartridge wears out from long-term usage. Manufacturers recommend periodically lubricating the elements with any kind of oil to reduce wear.
- Overload. If the technical characteristics of the model claim that it is designed for 200 lbs of load, then the person with a larger weight shouldn’t sit in the chair.
- Manufacturing defects. This situation is rare, but it also happens.
How to repair it yourself, at home
Now, when we know the reason of the chair sinking, let’s try to clarify how to repair it yourself, at home.
Before proceeding with the repair/replacement of the gas lift, it is necessary to prepare. To start:
- remove the armrests from the chair so they do not get in the way.
- the chair should be turned over so that you have free access to its bottom.
It would be reasonable to wear blinkers before proceeding, in case cylinder or lubricant particles fly towards your eyes.
- Use a screwdriver to unscrew the seat from the tilting mechanism.
- Now it is necessary to disassemble the gas lift. Hold the mechanism with one hand and gently knock on the piastre body (at the base of the crossbeam). At this stage, it is important not to damage the cylinder.
- The gas cartridge body remains attached to the crossbeam, so it must be detached. Turn the crossbeam over with the wheels upwards and with careful movements hit the center of the crossbeam so that the gas cartridge falls out of the body base.
- Now we are installing a new gas lift that will definitely hold the weight.
- Then the tilting mechanism should be attached back to the seat. We fasten the bolts, turn over the gas lift and insert the seat. There is no need to fix this action since the gas cartridge will fix itself immediately after the first time someone sits on it.
After the performed manipulations, it is necessary to check if everything is working correctly. To do this, just sit down and press the lever. If the mechanism freely raises and lowers the chair, then everything is in order and the work has been done successfully.