Q: How to Inspect and Refinish Brake Disc for Chevrolet Express and GMC Savana?
A: Initially, before inspecting the brakes, loosen the wheel lug nuts and raise your vehicle on jackstands. Also, don't forget to engage the parking brake before removing the wheels. While looking at its disc surface, check for any score marks or damages. Light scratches and slender grooves are general and don't interfere with brake performance; nonetheless, deep grooves need a disc that will be taken out and refinished by a machine shop. Check both sides of the disc. To verify if there is any warping in the disc, position a dial indicator about half an inch from outside edge of the disc and zero it out. Rotate the disc while ensuring that its runout limit specifications are not exceeded in reading by this instrument. If so happen it must be refinished (the disc). Refinishing disks is highly recommended when replacing brake pads to achieve smooth finish thereby ending any pulsation on braking pedal whatsoever. In case they are not resurfaced use emery cloth or sandpaper to take off glaze from their face up side or down side as well . In order to ascertain this one can measure its thickness using micrometer so as to see whether its not less than minimum thickness written on it For removals purposes only remove calipers leaving hoses intact just hang them somewhere aside On new models take away also caliper mounting bracket In case of front discs remove grease cap , wheel bearing retainer nut spindle nut outer bearing retainer washer and outer wheel bearing respectively before taking of the disc/hub For rear discs just pull them off from wheel studs only This is done contrary to removing it where you have got to put back caliper mounting bracket as well as tighten back wheel lug onto appropriate torque for it As we lower down our vehicle in inspection place all things secure.