Touched a thousand times, and suddenly nothing happens anymore. If pulling the lever under the seat of your office chair suddenly has no effect from one moment to the next, an essential component has given up the ghost: the gas lift. On budget chairs, this defect is roughly the equivalent of an "engine seizure" in a car. However, if you chose quality when buying your desk chair, you can easily repair or replace the part yourself and then get your swivel chair back in action.
Contents
- What can go wrong with a gas lift?
- Gas lift defective – what now?
- How does a gas lift work?
- Simple repair instructions
- Removing the gas lift
- Installing a new gas lift
WHAT CAN GO WRONG WITH A GAS LIFT?
There are two possible problems with a gas lift : First, the set height remains locked and can no longer be changed, no matter how much you bounce around on the seat. Second, the spring loses pressure and drops to its lowest position as soon as weight is placed on the seat. In addition, the seat is no longer cushioned. Assuming it is not a manufacturing defect – and therefore a warranty case that occurs shortly after purchase – such failures normally only become apparent after many years of use. How long a gas lift lasts under normal use is difficult to say – its service life varies from model to model. In almost all cases, however, the reason it stops working is that tiny particles combine with lubricant to form a mixture that causes the gas lift valve to stick or become blocked. So, in the broadest sense, this is a sign of wear and tear. With daily use in the major dust hotspot known as the office, where clouds of toner dust mix with dust stirred up by PC fans and stray carpet fibres, it is practically impossible to prevent tiny particles from collecting on the gas lift valve over the years. As a result, they get inside and cause it to stick or become blocked.
Either way, the faulty component has to be repaired – or removed completely.
GAS LIFT BROKEN – WHAT TO DO?
Before calling the caretaker, reaching for the toolbox or rushing out to buy a new chair, it is worth checking the paperwork first: How old is the chair? If it is still under warranty, send it straight back to the manufacturer. If that is no longer an option, there are two possible routes. The first is to repair the gas lift, which you can do yourself with a little skill. The second is to replace the faulty component, which can be ordered as a spare part from the manufacturer or your office chair retailer.
But only if the chair was bought from a specialist retailer. Cheap chairs from the supermarket, DIY store or discount furniture outlet are only rarely fitted with replaceable components. In these cases: hands off! A gas lift can be dangerous. Anyone who forcibly removes plastic parts that keep the spring under tension risks the piston shooting out of the cylinder uncontrollably and, in extreme cases, even breaking through the casing. Serious injuries may result, and in some cases careless DIYers have even lost their eyesight. In the best-case scenario, lubricant leaking from the cylinder will leave a huge mess.
As with all repairs, the rule is: better safe than sorry. Your health comes first, and if a procedure cannot be carried out according to the manufacturer's instructions, it is better to leave it to a professional.
HOW DOES A GAS LIFT WORK?
Even anyone who has never lain under an office chair in a mechanic’s pose removing plastic covers will most likely know the principle of a gas spring from its other areas of use: for example, on a car boot. When you open it, you can see two pistons on the right and left of the tailgate slowly extending and ultimately holding the boot lid open. This is made possible by a gas inside the piston that is compressed when closed and slowly expands when opened. The system is also being used more and more often for bonnets. Where older car models still required a support rod to be folded out and locked in place so the cover would stay open, a gas spring now extends and then supports the bonnet on its own. But how does such a pneumatic spring actually work?
Put simply, it essentially consists of a piston and a cylinder. Inside this cylinder is gas under high pressure. In most cases, this compressed gas is nitrogen. On the one hand, it is responsible for the spring force; on the other, it also serves for damping.
The amount of gas determines the spring force, which is why the piston is precisely matched to the fill volume. More complex designs feature a separating piston that allows the damping piston to run in oil and therefore be subjected to less friction.
It should be expressly pointed out once again that a gas spring must not be opened. Since the nitrogen inside the cylinder is under high pressure, the pneumatic component cannot be opened in a controlled manner, nor can the nitrogen be released in portions. The metal piston will quite literally fly at the tinkerer’s head.
SIMPLE REPAIR
The valve is located at the closed end of the cylinder, usually in the form of a ball or pin that is actuated by the lever. This is exactly where the weak point of the component lies: if dust particles collect around the edges of the fitting, they will eventually block the valve from closing smoothly. The result: it remains permanently open and, under weight load, allows the piston to compress the gas inside the spring. The other possibility is that a combination of dirt and lubricant causes the valve to stick. The result: the valve can no longer be opened – the gas spring remains closed.
It can help to treat this valve with standard multi-purpose sprays used as lubricants and cleaners. The lever should be actuated repeatedly to free up the valve closure. The cleaning agents and protective properties of these sprays, which are available in any DIY store and are ideal for hinges, bicycle cleaning or rusted screws, can loosen caked-on dirt and get the gas spring working smoothly again.
REMOVING THE GAS SPRING
If this repair attempt is unsuccessful, the only option left is to replace the faulty gas lift. All you need for this is a standard rubber mallet. This tool is normally used to drive wooden dowels into furniture, lay tiles or hammer tent pegs into the ground – but it also does a great job for the task at hand.
As a rule, you should know that the gas lift is only very rarely screwed to the base. Most modern office chairs are literally slot-together designs, which means that the tapered cylinder of the gas lift is inserted into the base so that it sits firmly in place. There are two ways to remove it. If you want to protect your back, lay the office chair on its side so that it is stable. Now hold the base steady with one hand and tap the protruding end of the gas lift cylinder carefully but firmly with the other hand. Feel free to rock the base vigorously back and forth and tap the defective part out of its fitting as carefully as possible. Next, grip the hard plastic sleeve of the gas lift firmly and tap all around the opening where the lift is inserted into the seat of your swivel chair or executive chair, indirectly applying force to the gas lift to loosen it.
The second method is just as effective, but it does require a little back strength: Lift your office chair by the seat and literally shake the gas lift together with the base out of its fitting. This way, you use the weight of the chair base, which should come free after a bit of shaking and rattling. Watch your feet so that the heavy metal or hard-plastic component does not fall on your toes! Now hold the base vertically and knock the gas lift out of its fitting from the side.
INSTALLING A NEW GAS LIFT
Before replacing the defective component with a new one, take the opportunity to give your office chair a thorough clean. You are unlikely to get such easy access to the individual parts of your office furniture again any time soon. The hard plastic parts in particular can be treated with the same spray you previously used in an attempt to get the old gas lift working smoothly again. First clean the individual parts with kitchen roll and glass cleaner, or with a soft cloth and a mild multi-purpose cleaner. Let the parts dry thoroughly, then take a spray oil and a soft cloth and carefully rub down all hard plastic parts.
The oil not only protects the surface, but also restores its shine. For chrome, you can either use a chrome cleaner from the DIY store – or rely on an old household remedy: citric acid. Cut a lemon in half and carefully rub any oxidised or tarnished chrome components. Alternatively, you can mix a solution from a handful of cold ash and a splash of water in a cleaned yoghurt pot. Carefully rub the affected parts, rinse with plenty of water and allow the clean chrome part to dry thoroughly. Afterwards, to prevent further corrosion, you can rub the whole thing with a thin layer of petroleum jelly.
Now take the new gas lift and carefully insert it into the opening in the base cross – if necessary, according to the instructions supplied by the manufacturer. There is no need to hit the cylinder with a hammer – especially as this could damage the new valve. Simply press it firmly into the opening, place the seat on top and sit down on the chair. Make absolutely sure that the lever used to operate the gas lift valve can move freely.