1999 GMC K1500 Suburban Brake Service (ONLINE REPAIR MANUALS)

General System

• Inspect components for damage or unusual wear. Replace as required.
• Inspect backing plate mounting bolts and ensure they are tight.
• Inspect wheel cylinders. Excessive fluid indicates cup leakage and need for wheel cylinder replacement. Slight amount of fluid is always present and is considered normal, acting as lubricant for cylinder pistons.
• Check adjuster screw operation. If satisfactory, lightly lubricate adjusting screw and washer with suitable brake lube. If operation is unsatisfactory, replace.
• C clean rust and dirt from shoe contact surfaces on backing plate using fi...

G Series

• Remove brake pipes from master cylinder. Plug pipes to prevent fluid contamination.
• Remove master cylinder attaching nuts and position master cylinder aside.
• Disconnect stop lamp switch electrical connector.
• Remove stop lamp switch retainer from brake pedal pin, then the stop lamp switch from brake pedal support.
• Disconnect power brake unit pushrod from brake pedal.
• Remove attaching nuts, then the power brake unit.
• Reverse procedure to install.
• Torque booster retaining nuts to 27 ft. lbs.
• Torque master cylinder retaining nuts to 27 ft. lbs.
• Torque brake pipe fittings...

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 t...

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 described 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 spri...

Certain general service procedures apply, regardless of whether the brakes are vacuum or hydraulically assisted. Only top quality, clean brake fluid should be used. More seals and valves are used with power brake systems than with ordinary brakes, so an inferior brake fluid will do much more damage. For the same reason, ensure all dirt is kept out of the system. Additionally, on models with hydraulic assist brakes, care must be taken not to mix the fluids of the booster hydraulic system and brake hydraulic system as the fluids are not compatible.

If the power unit fails, the brak...

2WD Models

Except Montana, Silhouette, Trans Sport & Venture

Front

• Raise and support vehicle.
• Remove tire and wheel assembly.
• Remove caliper as outlined under "Caliper Service."
• Remove grease cap from hub/rotor, Fig. .
• Remove cotter pin, nut and washer.
• Remove hub/rotor from spindle, being careful not to damage spindle threads or outer bearing.
• Reverse procedure to install, noting the following:
• Apply high-temperature wheel bearing grease to inner and outer wheel bearings.
• Torque nut to 12 ft. lbs. while turning wheel assembly forward by hand, back nut off one flat or until hole in spindle...