<P> Other vehicles of the 1960s era, including some Vauxhalls, had lower ball joints with considerable end float, because the joint was always in tension as the spring and damper loads were applied via the lower control arm and were always non-zero . </P> <P> Another example is the Ford Focus, which uses MacPherson struts, and the anti-roll bar is connected directly to the strut, so the lower ball joint is only carrying fore and aft traction / braking and lateral cornering loads . </P> <P> Unlike a kingpin, which requires an assembly in the center of the wheel in order to pivot, joints connect to the upper and lower end of the spindle (steering knuckle), to the control arms . This leaves the center section open to allow the use of front - wheel drive . Older kingpin designs can only be used in a rear - wheel - drive configuration . </P> <P> Sealed ball joints do not require lubrication as they are "lubed for life". Formerly most ball joints had grease fitting (sometimes called a grease zerk) and were designed for periodic addition of a lubricant, however almost all modern cars use sealed ball joints to minimise maintenance requirements . The lubricant was usually a very high - viscosity lubricant . It is commonly believed that standard ball joints will outlive sealed ones because eventually the seal will break, causing the joint to dry out and rust . Additionally, the act of adding new lubricant pushes out old and dry lubricant, extending the life of the joint . This was supposed to be done at intervals of 1000 to 2000 miles on many vehicles, which is incompatible with the service interval on modern cars, often 12000 miles or more, and in any case was rarely attended to by owners, resulting in severe wear and possible ball joint failure, which can result in serious accidents . For this reason, almost all ball joints on modern European or Far Eastern cars are the sealed for life type . New technology especially applied to the internal bearing design has allowed ball joints to meet these longer service intervals . The special design's incorporate sintered metal bearings which replace OEM sealed polymer / plastic version and improved dust boot seal's that work much better at retaining the grease . </P>

Is a ball joint the same as a wheel bearing