I have an office chair with five wheels. When you lean forward or back, it creaks. What can be done to eliminate the creak?
To find the exact spot where the squeak originates, use a meter-long piece of 3/4" heater hose or vinyl tubing. While you squeak the chair, your assistant uses the tubing like a stethoscope to find the loudest point under the chair.
Once you have found the point, mark it with a pen or chalk. It could be metal-to-metal, metal-to-plastic, or plastic-to-plastic. It could be in the center support, in an adjustment plate, or in the seat bottom or back.
You could spray something, rub a wax crayon, or sprinkle powder, depending on the exact location. Good luck, and keep trying.