GM Service Manual Online
For 1990-2009 cars only
  1. Inspect the linings when you remove the wheels and as suggested in the maintenance schedule located in Maintenance and Lubrication.

  2. Object Number: 178624  Size: SH
  3. Inspect both ends of the outer pad (3) by looking through the lining inspection hole (1) in the caliper. These are the points where the highest rate of wear normally occurs. At the same time, inspect the thickness of the inner pad (3) in order to ensure that the pad has not worn prematurely. Replace the pad if the minimum thickness is less than 1 mm (0.04 in).