Office Chair Hydraulic Leakage

If the hydraulic system of an office chair leaks air, the entire hydraulic rod needs to be replaced as it cannot be repaired. The replacement process is as follows:

I. Safely Remove the Old Hydraulic Rod

1. Prepare Tools: A large pipe wrench (or adjustable wrench), rubber mallet, gloves, and safety goggles.
2. Separate the Five-Star Base: Turn the chair upside down. Use the pipe wrench to grip the metal collar connecting the hydraulic rod to the five-star base. Rotate it vigorously counterclockwise (usually reverse-threaded). If necessary, apply lubricating oil to aid in disassembly.
3. Separate the Seat:
   • For a "snap-ring" connection, use a screwdriver to pry open and remove the metal snap ring, then pull out the hydraulic rod.
   • For a "screw-fixed" connection, unscrew the fixing screw at the center of the seat base to separate it.

II. Accurately Measure and Purchase a New Rod

1. Measure Dimensions:
   • Total Length: The shortest length when the hydraulic rod is fully compressed.
   • Tube Diameter Grade: The common grades are Class 3 (inner tube diameter ≈ 33mm, outer tube diameter ≈ 48mm) or Class 4 (thicker). Use calipers to measure the outer tube diameter of the original rod.
   • Stroke: The difference between the maximum extension and minimum compression lengths.
2. Purchase a New Rod: Bring the old rod or a precise photo of its dimensions. Choose to buy a new hydraulic rod of the same size, grade, and with safety certifications (such as SGS/BIFMA) online or at a hardware store. The price is approximately 30-100 yuan.

III. Install the New Hydraulic Rod

1. Clean the Interfaces: Clean the threads or interfaces of the five-star base and the seat base to ensure they are free of impurities.
2. Connect to the Five-Star Base: Align the bottom thread of the new rod with the five-star base and rotate it clockwise to tighten (first by hand, then slightly tighten with a pipe wrench).
3. Install the Seat: Insert the top end of the rod into the seat base and install the snap ring or fixing screw.
4. Test the Function: Place the chair upright and raise and lower it several times to check if it operates smoothly and locks firmly.

IV. Precautions

1. Risks of Non-Standard Methods:
   • Using a metal tube to manually control the height may affect stability.
   • Replacing the air pump poses safety risks. It is recommended to seek professional help or on-site repair services.
2. Preventive Maintenance: Avoid frequent rapid raising and lowering and overloading. Keep the rod body clean and dust-free to extend the lifespan of the hydraulic rod.