What does the ball joint gauge measure?

The ball joint gauge is specifically designed to assess the condition of the load-carrying ball joint by measuring its looseness. A properly functioning ball joint should have minimal play; excessive looseness can indicate wear or damage that could affect vehicle handling, steering, and safety. Monitoring the looseness helps ensure the ball joint can properly support the vehicle's weight and maintain the required alignment as it interacts with the suspension system. A significant amount of play discovered through this measurement may warrant further inspection or replacement of the joint to prevent any potential safety hazards while driving.

Other options, while they reference parts of the vehicle or characteristics that could be evaluated, do not correctly define the primary function of the ball joint gauge. For instance, it does not measure the overall structural integrity of the joint or the weight capacity, as these would require more comprehensive assessments beyond what the gauge specifically targets. Similarly, the horizontal movement of the vehicle pertains to dynamics that are not measured by the ball joint gauge itself.