2002 GMC Yukon XL 1500 Brake Service (ONLINE REPAIR MANUALS)

Disassemble

• Place accumulator compressor tool No. J-26889, or equivalent, around end of accumulator.
• Install nut onto stud as in. Fig. , then depress accumulator with a C-clamp.
• Remove retainer by using a punch.
• Release C-clamp and remove accumulator compressor tool.
• Remove accumulator, O-ring, retainer, plug and spring,. Fig. .
• Remove retainer, output pushrod, baffle, piston return spring and retainer.
• Cut off eyelet of pedal rod, then remove boot.
• Remove nut, bracket and bolts, then separate cover from housing.
• Remove piston assembly and seals.
• Remove spool valve, then the accu...

C & K Series

Duo-Servo

Removal

• Raise and support vehicle.
• Mark relationship of wheel to hub, then remove tire and wheel assembly.
• On models equipped with full-floating axles, remove hub and drum assembly as outlined in. "Drive Axles."
• On models equipped with semi-floating axles, proceed as follows:
• Install pin into park brake lever.
• Mark relationship of drum to axle.
• Remove rear brake drum retainers, as required.
• Remove rear brake drum.
• On all models, remove return springs and shoe guide,. Fig. .
• Remove brake hold down springs and pins.
• Disconnect actuator lever and pivot.
• Remove lever return sp...

Delco Master Cylinder

When performing the following procedures, refer to. Figs. and , noting that the composite reservoir may vary in design.

Disassemble

• Remove master cylinder from vehicle.
• Remove reservoir cover and diaphragm. Discard old brake fluid in reservoir.
• Inspect cover and diaphragm. Replace if cut, cracked or deformed.
• Remove fluid level switch and proportioning valve assembly, if equipped.
• Depress primary piston and remove lock ring.
• Plug primary fluid outlet (outlet nearest to cowl when master cylinder is installed), then apply compressed air into secondary fluid outlet...

When working on or around brake assemblies, care must be taken to prevent breathing asbestos dust, as many manufacturers incorporate asbestos fibers in the production of brake linings. During routine service operations, the amount of asbestos dust from brake lining wear is at a low level because of a chemical breakdown during use and a few precautions will minimize exposure.. Do not sand or grind brake linings unless suitable local exhaust ventilation equipment is used to prevent excessiv...

In order to properly service power brake systems, a thorough understanding of the power assist system is required. These systems provide a mechanical assist, acting to increase the force applied to the master cylinder piston by the driver while decreasing the effort required to obtain acceptable stopping performance.

Hydraulic assist units incorporate a basic open center spool valve, hydraulic cylinder and an accumulator assembly in a common housing. When the brake pedal is depressed, the hydraulic piston moves forward closing off fluid relief passages, the spool valve applies fluid ...

Brake Lines & Linings

Remove one of the front wheels and inspect the brake disc, caliper and linings.

Do not allow any oil or grease on the linings. It is recommended that linings be replaced in sets when worn or damaged.

If the caliper is cracked or fluid leakage through the casting is evident, it must be replaced as a unit.

Brake Roughness

The most common cause of brake chatter on disc brakes is a variation in thickness of the disc. If roughness or vibration is encountered during highway operation or if pedal pumping is experienced at low speeds, the disc may have excessive thickness v...