Tricresyl phosphate (TCP) is an important extended-pressure additive in lubricating oils. Its depletion from reservoir oil could constitute a failure mechanism for bearing system. The interaction of TCP with bearing retainer and reservoir materials was investigated using an apparatus that mimicked centrifugal oil feed. TCP was not selectively absorbed by cotton-phenolic retainer or wool felt reservoir materials, but was absorbed by nitrile-acrylic and sintered nylon reservoir materials, which exhibited significant TCP retention. The results are discussed in terms of the degree of bulk oil absorption, the availability of polar sites on the sorbents, and the interaction between such sites and the TCP molecules.Presented at the 39th Annual Meeting in Chicago, Illinois, May 7–10, 1984