Office chairs are complex mechanisms designed to support your body in various positions throughout the workday. When these mechanisms fail, it can lead to discomfort, reduced productivity, and potentially even injury. At Chair Masters, we've repaired thousands of office chairs across Canada, and we've encountered virtually every mechanism problem imaginable.
In this comprehensive guide, we'll explore the most common chair mechanisms, how they work, what typically goes wrong, and how to troubleshoot problems before deciding whether to repair or replace your chair.
Understanding Common Office Chair Mechanisms
1. Pneumatic Gas Cylinders
The pneumatic gas cylinder is perhaps the most essential mechanism in a modern office chair, allowing for height adjustment with minimal effort.
How it works: A pneumatic cylinder contains pressurized nitrogen gas and oil. When you pull the height adjustment lever, it releases a valve that allows the gas to move within the chamber, enabling the chair to move up or down. When you release the lever, the valve closes, locking the chair at the desired height.
Common problems:
- Chair gradually sinks: This is the most common gas cylinder issue, occurring when the seal inside the cylinder begins to fail, allowing gas to slowly leak between chambers.
- Chair won't adjust at all: The valve mechanism may be stuck or broken.
- Chair drops suddenly: A complete seal failure in the cylinder can cause the chair to drop without warning.
- Cylinder rotates when swiveling: The cylinder can become loose from the chair base over time.
DIY troubleshooting:
- For chairs that gradually sink, try using a hose clamp or jubilee clip around the cylinder to prevent the cylinder from descending when weight is applied.
- Ensure the chair is properly assembled and that the cylinder is securely seated in both the chair base and seat plate.
- Apply lubricant to the lever mechanism if the height adjustment is stiff.
When to call a professional: If your DIY fixes don't work, or if the cylinder is completely non-functional, it's time for a replacement. Professional technicians can safely remove the old cylinder and install a new one that matches your chair's specifications.
2. Tilt Mechanisms
Tilt mechanisms allow the chair to rock backward and forward, providing dynamic seating positions that can reduce fatigue during long workdays.
Types of tilt mechanisms:
- Basic Tilt: The entire seat and backrest tilt from a pivot point under the front of the seat.
- Knee-Tilt: Pivots from a point near the front of the seat, reducing the sensation of your feet lifting off the floor when reclining.
- Synchro-Tilt: The backrest reclines at a greater ratio than the seat (typically 2:1) to maintain proper ergonomics in all positions.
- Multi-Function Tilt: Allows the backrest and seat to be adjusted independently of each other.
Common problems:
- Excessive play or wobbling: Worn pivot points or loose connections.
- Stiff or difficult reclining: Tension adjustment may be set too high, or the mechanism may need lubrication.
- Too much recline or inability to lock position: Failed tilt lock mechanism.
- Squeaking or grinding sounds: Metal-on-metal contact due to lack of lubrication or component wear.
DIY troubleshooting:
- Inspect all visible bolts and tighten any that are loose.
- Adjust the tilt tension knob (usually a large knob under the seat) to increase or decrease resistance when reclining.
- Apply silicone-based lubricant to moving parts if you hear squeaking.
- Make sure the tilt lock is fully engaged when attempting to lock the position.
When to call a professional: Tilt mechanisms with stripped gears, broken springs, or significant metal fatigue often require complete replacement. This is precision work that typically requires disassembly of the chair and specialized tools.
3. Armrest Mechanisms
Modern office chairs come with a variety of armrest adjustment options to support different tasks and body types.
Common armrest adjustments:
- Height adjustment: Allows armrests to be positioned at the correct height to support the elbows.
- Width adjustment: Enables armrests to be moved closer or further from the body.
- Depth adjustment: Permits armrests to slide forward or backward.
- Pivot adjustment: Allows armrests to angle inward or outward.
- 3D/4D armrests: Combine multiple adjustment types for maximum flexibility.
Common problems:
- Armrests won't stay in position: Worn locking mechanisms or internal teeth.
- Armrests feel loose or wobbly: Loose bolts or worn connection points.
- Adjustment buttons or levers not working: Internal mechanism failure or obstruction.
- Cracked or damaged armrest pads: Material fatigue or impact damage.
DIY troubleshooting:
- Tighten visible bolts connecting the armrests to the chair seat.
- Check if adjustment buttons are fully engaging/disengaging when pressed.
- Remove the armrest pad (if possible) to inspect internal mechanisms for obstructions.
- For height-adjustment issues, try pulling the armrest all the way up and then gradually lowering it to the desired position.
When to call a professional: If internal mechanisms are broken or if armrest mounting points are damaged, professional repair is usually the best option. Armrest assemblies often need to be replaced as complete units.
4. Backrest Mechanisms
Backrest mechanisms control the angle, height, and sometimes the shape of the chair's back support.
Common backrest adjustments:
- Height adjustment: Raises or lowers the backrest on chairs with separate seat and back components.
- Angle adjustment: Changes the angle of the backrest relative to the seat.
- Lumbar support adjustment: Modifies the position or firmness of the lumbar support.
- Ratchet back: A stepped height adjustment system that clicks into preset positions.
Common problems:
- Backrest slides down: Worn ratchet mechanism or loose friction components.
- Limited or no angle adjustment: Broken adjustment lever or internal mechanism failure.
- Lumbar support not holding position: Worn adjustment knob or broken internal components.
- Backrest feels loose or unstable: Loose bolts or cracked support brackets.
DIY troubleshooting:
- Inspect and tighten all visible bolts connecting the backrest to the chair.
- For ratchet back systems, raise the backrest beyond the highest position until you hear a click, then lower to the desired height.
- Check adjustment levers for full range of motion and proper engagement.
- If the backrest frame is metal, look for hairline cracks that might be causing instability.
When to call a professional: If the backrest frame is bent or broken, or if internal adjustment mechanisms have failed, professional repair is usually necessary. Structural issues with the backrest should never be ignored as they can lead to injury.
Common Repair Tools and Parts
If you're comfortable with DIY repairs, having these tools and parts on hand can help address many chair mechanism issues:
Essential Tools:
- Allen wrench set (hex keys): Most chair bolts use hex heads.
- Phillips and flathead screwdrivers: For various screws and adjustments.
- Adjustable wrench: For larger nuts and bolts.
- Rubber mallet: For seating components without damaging them.
- Penetrating oil (WD-40 or similar): For lubricating stuck mechanisms.
- Silicone spray lubricant: For moving parts where oil isn't appropriate.
- Pipe wrench: Specifically for removing stubborn gas cylinders.
Commonly Replaced Parts:
- Gas cylinders: Available in different lengths and weight capacities.
- Casters: Come in various types for different floor surfaces.
- Chair bases: Usually made of nylon, aluminum, or steel.
- Armrest pads: Often the first component to show wear.
- Tilt control mechanisms: Complete assemblies that mount under the seat.
- Bushings and washers: Small parts that reduce friction in moving components.
When to Repair vs. When to Replace
Not all chair problems warrant repair. Here's our guidance on when to fix and when to replace:
Consider Repair When:
- The chair is less than 5 years old and was originally of good quality.
- The issue is isolated to a single, replaceable component.
- Replacement parts are readily available.
- The cost of repair is less than 50% of the cost of a new, comparable chair.
- The chair has sentimental value or matches existing office furniture.
Consider Replacement When:
- Multiple mechanisms are failing simultaneously.
- The chair frame is damaged or structurally compromised.
- Replacement parts are no longer available or cost-prohibitive.
- The chair design doesn't meet current ergonomic standards.
- Repair costs approach or exceed 50% of the cost of a new chair.
Preventive Maintenance for Chair Mechanisms
Extending the life of your office chairs is easier than you might think. Follow these preventive maintenance tips:
- Regular cleaning: Dust and debris can accumulate in mechanisms and cause premature wear.
- Scheduled lubrication: Apply silicone spray to moving parts every 6 months.
- Fastener checks: Tighten all visible bolts quarterly, or whenever the chair feels loose.
- Weight limits: Respect the manufacturer's stated weight capacity for the chair.
- Balanced use: Avoid leaning heavily to one side repeatedly, which can strain mechanisms unevenly.
- Floor protection: Use appropriate casters for your floor type to reduce strain on the chair base.
- Environmental considerations: Extreme temperatures and humidity can affect lubricants and materials.
Extending the Life of Your Office Chairs: Professional Maintenance Programs
For businesses with multiple office chairs, professional maintenance programs offer significant value:
- Scheduled inspections: Identify and address minor issues before they become major problems.
- Fleet management: Track the condition and repair history of all chairs in your organization.
- Warranty protection: Regular maintenance may be required to maintain manufacturer warranties.
- Bulk replacement parts: Maintain an inventory of common parts for quick repairs.
- Employee training: Proper chair use and adjustment can prevent mechanism damage.
Conclusion
Understanding office chair mechanisms is the first step in addressing problems when they arise. Many issues can be resolved with simple adjustments or minor repairs, potentially saving your business the cost of replacement chairs. However, knowing when to call in professional help is equally important to ensure safety and proper function.
At Chair Masters, we specialize in breathing new life into office chairs through expert mechanism repair and replacement. Our technicians are trained in the intricacies of all major chair brands and models, ensuring that repairs are done correctly the first time.
Whether you need a single chair repaired or are looking to establish a maintenance program for your entire office, we're here to help keep your seating in optimal condition for years to come.