What’s the best rule of thumb for ball joint freeplay? Play it super-safe and replace it whenever you notice any slop between the linkage, or wait until it wants to fall out? The answer is “Hook your thumb back behind your suspenders; there is no rule of thumb. Check the manufacturer’s specs.” Ball and socket joints aren’t the same as they were, so no one rule fits them all any more. We’ll look at some of the different kinds of joints to understand not just what we’re doing, but why. I talked with Allen Mytyk, manager of technical training for Federal Mogul, to find out not just when a ball might fall out of its socket, but when the freeplay becomes enough to affect the alignment and steering control. The good stuff here is mostly his; any mistakes are mine.