This paper presents our recent studies on the effect of BSA aqueous solution on a steel slider bearing surface using a self-developed optical slider test rig [19]. The lubricating film is bound by a stationary steel plane and a moving glass surface to facilitate the measurements of film thickness and monitor the events occurring on the bearing surface with BSA solvent. Different from the optical EHL test set up [16], [17] and [18], the present slider test rig provides a conformal bearing contact and the lubrication is purely under hydrodynamic regime. The conditions within the contact in terms of pressure and shear rate are readily obtained using hydrodynamic theory.