The Mazda ball joints are suspension components that are also connected to the steering system on your vehicle. On most vehicles there are either two or four of these components. They are located in the front wheel assemblies connected to the upper and/or lower ends of the spindles. The ball joints are the rotational device that makes it possible for the wheels on your Mazda to turn so maneuvering is possible. The upper ball joint is located in the upper wishbone or A-frame of the vehicle. The lower one is in the control arm or lower A-frame of the vehicle. Since this suspension component moves in a socket, it has to be lubricated periodically or the friction it experiences will cause premature wearing of it. The only way to lubricate these components is to lift the vehicle into the air with the wheels suspended, then grease can be injected into them. This should be part of the routine greasing of the steering and suspension components on your Mazda is in the shop receiving an oil change. If the greasing of the ball joints occurs when the vehicle is resting on the pavement with the weight of the vehicle on them, then the grease will not be able to cover the entire joint. Unfortunately, the sections that will not receive the grease are the areas that need it the most. Because of this the ball joints will then have premature wearing on them. Inspection of the Mazda ball joints can only occur when the wheels are suspended in the air. By grasping the top and bottom of the wheel the amount of play should be noted. Basically if you can feel movement in these components, they should be replaced so your Mazda will be safe to operate.