Last week I noticed that my 87 90 2.5 na was pulling to the left under braking , i pulled the front os wheel off . on inspection i found the disc to be covered in a black oily mess . Gave it a good clean up banged in a new set of pads . Things went ok for a day or two , but the pulling to the left slowly returned . Again when i inspected the disc it had an oily covering . There is no brake fluid leaking . Is it possible that the oil is coming from the Swivel Housing along the half shaft ? Any ideas ?