Q: How to Inspect and Replace Brake Disc on Chevrolet Blazer,S10,GMC Jimmy and Sonoma?
A: To inspect the brakes, begin by loosening wheel lug nuts and raising the front of the vehicle on jack stands. Take off the wheel followed by the brake caliper. While checking for any score marks or damage on disc surfaces, remember that slight scratches and shallow grooves are normal and will not affect the brake operation. Nevertheless, deep grooves of over 0.015-inch deep necessitate disc removal and refinishing at a machine shop. Make sure both sides have been inspected thoroughly. When inspecting a rear disc, reinstall wheel lug nuts with flat side towards disc to hold it in a flat vertical plane during inspection. Washers may be needed under lug nuts to apply pressure to disc. To check for disc runout, place dial indicator about 1/2 inch from outer edge of disc and zero it out. Turn disk around while making sure that reading does not exceed 0.003 inches on indicator gauge; if it does so, then let machine shop refinish disk for you.Additionally don't allow multiple groves on your brake rotors which should be well maintained as long as they don't wear below specified minimum thickness.It is also possible to measure rotor thickness with micrometer.For removal and installation, on 2WD models, the disk is part of the front hub assembly and should be removed and installed according to front wheel bearing maintenance procedure.On 4WD models remove tire; remove caliper , then pull off disk from its mounting onto hub.