What is the appropriate action if a truck's kingpin bores exceed the manufacturer's specifications?

When kingpin bores exceed the manufacturer's specifications, the most appropriate action is to check for oversized kingpins as a solution. This approach is correct because oversized kingpins can compensate for wear in the bores, thus restoring proper alignment and steering function without the need for extensive modifications or part replacements.

By using oversized kingpins, a technician can potentially resolve the issue of excessive wear while ensuring that the truck maintains safe handling characteristics. This method is often a cost-effective solution that avoids the need for replacing major components, such as the entire axle, which could be more expensive and time-consuming.

Other options would not adequately address the problem. For instance, using shims could provide a temporary fix, but it does not solve the underlying issue and might lead to further premature wear. Installing standard kingpins would be ineffective since they would not fit properly within already worn kingpin bores. Replacing the axle is a more drastic measure that would not be necessary if oversized kingpins can restore the function effectively and safely.