If your headrest is not holding its position properly under normal use, the most common cause is misaligned bearings. Depending on the direction the headrest is moving, a different set of bearings may be responsible:

• Vertical Movement Issues
  If your headrest is not holding a locking position and drifting down, the likely cause is misaligned lower bearings. These are located at the base of the arm mechanism and can affect controlling the vertical locking mechanism. Refer to the section How to Inspect and Realign the Lower Bearings below for further instruction.

• Horizontal Movement Issues
  If your headrest is shifting forward or backward, the likely cause is misaligned upper bearings. These are located at the top of the arm mechanism and control the horizontal (tilt) adjustment. Refer to the section How to Inspect and Realign the Upper Bearings below for further instruction.

When bearings shift out of proper alignment, the adjustment mechanism cannot tighten correctly, leading to difficulty holding the headrest firmly in the desired position.

1. Remove the headrest from the chair for the best visibility and access to the internal components.
2. Use a Phillips head screwdriver to remove the two screws located on the outside of the arm mechanism.
3. Fully unscrew the knob located at the bottom of the arm mechanism.
4. Remove the knob, then gently pop off the back plate by pressing on the exposed bolt.
5. Inspect the lower bearings:
1. Each bearing has a gap running lengthwise.
2. These gaps should face outward, away from each other.
3. Confirm both bearings are properly seated inside the indentations of the top cover.
6. Replace the back plate and bolt, ensuring you align the key and key slot.
   
7. Reinstall the two screws you removed earlier to reassemble the arm mechanism.
8. Reattach the headrest to the chair, tighten the knob and washer to your desired tension, and test the vertical tension of the headrest.