What maintenance step is essential when replacing a rear wheel bearing seal?

When replacing a rear wheel bearing seal, ensuring proper seating of the seal is critical. Proper seating is necessary because an improperly seated seal can lead to leaks, which may cause contamination of the bearing and ultimately lead to bearing failure. A correctly seated seal ensures that it will effectively keep grease in and contaminants out, maintaining the integrity of the bearing assembly.

While cleaning the bearing surface and applying grease to the new seal are important maintenance steps, they are additional to the primary requirement of ensuring the seal is seated correctly. Cleaning helps prepare the surface for the seal and can prevent potential damage or improper sealing, while applying grease can assist in installation and extend the seal's life by reducing friction. However, none of these measures will be effective if the seal is not properly seated. Thus, proper seating is the essential step in this process.