Workshop Repair and Service Manuals GMC SIERRA
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00-05-22-002N Disc Brake Warranty Service and Procedures - (May 31 2013) Disc Brakes - part 9

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The customer may toleratethe condition until it becomes very apparent.If a GM dealer performed a prior brake service, consider paying for the repair andthen strongly reinforce proper brake lathe maintenance.If the customer had the brake service done outside of a GM dealership, normally GMwould not offer any assistance.If a customer indicated they had wheel service, ask who performed the service. Then;If a GM dealer performed the service, consider paying for the repair and then stronglyreinforce the use of torque wrenches at the dealer. Two common size torque wrenchescover 90% of all GM products. Each technician needs to use torque wrenches properlyevery time the wheel nuts are tightened.If the customer had the wheel service done outside of a GM dealership, normally GMwould not offer any assistance.Thickness Variation Pulsation Caused by Brake Rotor Corrosion — Rotor corrosion isanother form of thickness variation, which can cause a pulsation concern and can beaddressed as follows:Cosmetic Corrosion:

In most instances rotor corrosion is cosmetic and refinishing the rotor is unnecessary.

Corrosion — Pulsation Caused by Thickness Variation (Lot Rot / Low Miles — 0–321-km(0–200 mi):

At times more extensive corrosion can cause pulsation due to thickness variation.This usually happens when the vehicle is parked for long periods of time in humidtype conditions and the braking surface area under the pads corrodes at a differentrate compared to the rest of the brakingsurface area. Cleaning up of braking surfaces (burnishing) can be accomplished by10 – 15 moderate stops from 56– 64-km/h (35 – 40-mph) with cooling time between stops.If multiple moderate braking stops do not correct this condition, follow the “BrakeRotor Clean-Up Procedure” below.

Corrosion — Pulsation Caused by Thickness Variation (without rotor flaking / highermileage — 3,200-8,000-km (2,000-5,000-mi):

In some cases, more extensive corrosion that is not cleaned up by the brake pad overtime and miles can cause the same type of pulsation complaint due to thickness variation.In these cases, the rotor surface is usually darker instead of shiny and a brakepad foot print can be seen against the darker surface. This darker surface is usuallydue to build-up, on the rotor material surface, caused by a combination of corrosion,pad material and heat. To correct this condition, follow the “Brake Rotor Clean-upProcedure” below.

Corrosion — Pulsation Caused by Thickness Variation (with rotor flaking / higher mileage— 8,000 + km (5,000 + miles):

Important:In some flaking instances, cleaning-up this type of corrosion may require more rotormaterial to be removed then desired. Customer consideration should be taken in thesesituations and handled on a case by case basis, depending on the amount/percentageof rotor life remaining and the vehicle's warranty time and miles.

BRAKE ROTOR CLEAN-UP PROCEDURE

Clean-up the rotors on an approved, well-maintained brake lathe to guarantee smooth,flat and parallel surfaces.

Brake Drum Refinishing Drum Brakes     Special ToolsJ 41013 Rotor/Drum Flange Resurfacing KitJ 42450-A Hub Cleaning Kit Warning:Refer toBrake Dust Warning. The brake drums do not require refinishing as part of routine brake system service.Do not refinish brake...
Brake Pedal Travel Measurement and Inspection (Non-Hybrid) Hydraulic Brakes Brake Pedal Assembly     Special Tools J-28662 Brake Pedal Effort Gauge With the ignition OFF and the brakes cool, apply the brakes 3–5-times, or until thebrake pedal becomes firm, in order to deplete the brake booster power reserve.Install the...
Exhaust Brake     The heavy duty diesel pickups have an exhaust brake toenhance the vehicle brake system, and reduce brake lining wear. Aswitch is used to activate the system, and is located below theclimate controls in the center of the...
Parking Brake Cable Adjuster Enabling Parking Brake Cable     Hold the park brake pedal in the FULL upward position. Pull rearward on the front park brake cable until the tensionis released from the tool-(1) installed in the pedalassembly.Remove the tool-(1).Slowly release the park...
Brake Rotor Assembled Lateral Runout Correction Disc Brakes Brake Rotors     Note: Brake rotor thickness variation MUST be checked BEFOREchecking for assembled lateral runout (LRO). Thickness variationexceeding the maximum acceptable level can cause brake pulsation.Refer toBrake Rotor Thickness...
Brake System Warning Light     With the ignition on, the brake system warning light comes on when the parking brakeis set. If the vehicle is driven with the parking brake engaged, a chime sounds whenthe vehicle speed is greater than 8-km/h (5-mph). The...