Single direction thrust ball bearings consist of a shaft washer and a ball and cage thrust assembly.The bearings are separable so that mounting is simple as the washer and the ball and cage assembly can be mounted separately.Double direction thrust ball bearings consist of one shaft washer ,two housing washers and two ball and cage thrust assemblies.The bearings are separable so that mounting is simple.The various parts can be mounted separately.The housing washer and ball and cage thrust assemblies are identical to those of the single direction bearings.