Final answer:
If the spindle is missing the hardened stamp when repacking a bolt-on hub, this indicates possible lack of proper heat treatment or wear, which compromises spindle strength and safety. Replacement of the spindle is advised to maintain hub assembly integrity.
Step-by-step explanation:
When inspecting and repacking a bolt-on hub, it is crucial to examine the spindle for wear and damage. If during this inspection the spindle is found to be missing the hardened stamp, this typically indicates that the spindle may not have been heat-treated or that the mark has worn off due to use or improper maintenance. The absence of the hardened stamp is significant as it suggests that the spindle might not possess the required hardness and strength, which are critical for its performance and safety. Without the proper heat treatment, the spindle might be more susceptible to wear and failure, which can lead to hazardous situations on the road. Therefore, it is generally advised to replace a spindle missing the hardened stamp to ensure the safety and reliability of the hub assembly.