The sealing rings are synthetic resin with chamfered ends. Check the condition of the sealing rings, and replace them only if they are worn, distorted, or damaged.
For a better fit, squeeze sealing rings together slightly before installing them.

Apply ATF to the new sealing rings, then install them on the secondary shaft.

After installing the sealing rings, verify the following:
The rings are fully seated in the groove.
The rings are not twisted.
The chamfered ends of the rings are properly joined.
Numbers
...
Cylinder Head Cover Removal
Remove the intake manifold chamber.
Disconnect the four ignition coil connectors (A).
Remove the harness holder (B) and the breather hose (C).
Remove ...
Ball Joint Boot Inspection/Replacement
Special Tools Required
Bearing Driver Attachment, 40 mm 07GAF-SE00200
Check the ball joint boot for weakness, damage, cracks, and grease leaks.
NOTE:
If the ball joint boot is ...