Final answer:
Replace the CV joint boot if it has a small split to protect the CV joint and ensure longevity. Sealing it is only a temporary fix and may lead to premature failure. A complete half-shaft assembly replacement may be required if the joint is damaged.
Step-by-step explanation:
If a CV joint boot is found to have a small split, the best course of action is to replace the boot (A). While it is possible to seal a boot with adhesives like ATV or Permatex as a temporary fix, these are not long-term solutions. Continuing to drive with a damaged boot can allow dirt, debris, and moisture to enter the joint, which can lead to premature failure. Therefore, replacing the boot as soon as possible is recommended to protect the CV joint. In some cases, if the damage is too severe or the CV joint itself has been compromised, replacing the entire half-shaft assembly (B) may be necessary.