1999 Chevrolet Blazer Brake Service (ONLINE REPAIR MANUALS)

Height Sensing Proportioning Valve

The height sensing proportioning valve must be adjusted whenever the valve and/or linkage is disassembled or removed for service. In addition, adjustment should be checked if excessive front wheel lock-up is experienced with a lower than desired brake application rate when vehicle is at or near maximum GVWR.

• Raise and support vehicle, leave wheels on and allow axle to hang freely.
• Remove lever retaining nut and disconnect lever from valve shaft, Fig. .
• Rotate valve shaft to permit installation of correct adjustment gauge, Fig. , ensure D shaped ho...

Disassemble

• Place accumulator compressor tool No. J-26889, or equivalent, around end of accumulator.
• Install nut onto stud as shown in Fig. , then depress the 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.
• Using a suitable saw, cut off eyelet of pedal rod, then remove the boot.
• Remove nut, bracket and bolts, then separate cover from housing.
• Remove piston assembly and seal...

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, 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 brakes will still operate, as the convention...

Battery Ground Cable

Prior to service disconnect battery ground cable and isolate as required.

Radio Security System

Theftlock

If the Theftlock system is active when battery power is interrupted, the customers security code must be entered to restore proper function of the radio. To unlock a secured radio after power loss, proceed as follows:

• "LOC" appears with ignition in On position.
• Press "NM" and "000" will appear on display.
• Press "NM" again to make last two digits agree with security code.
• Press "HR" to make first 1 or 2 digits agree with security code.
• Press "AM-FM" to select code entered. "SEC" wi...

Astro & Safari

• Apply parking brake.
• Disconnect reservoir and power steering hoses from booster.
• Remove master cylinder to brake booster retaining nuts.
• Position and support master cylinder away from booster. Do not remove hydraulic lines from master cylinder.
• Remove booster rod from top of brake pedal.
• Remove booster mounting nuts from inside of vehicle.
• Remove booster assembly and gasket.
• Reverse procedure to install, noting the following:
• Torque booster mounting nuts to 27 ft. lbs.
• Torque master cylinder retaining nuts to 27 ft. lbs.
• Torque power steering hoses to booster n...

Astro & Safari

• Apply parking brake.
• Disconnect reservoir and power steering hoses from booster.
• Remove master cylinder to brake booster retaining nuts.
• Position and support master cylinder away from booster. Do not remove hydraulic lines from master cylinder.
• Remove booster rod from top of brake pedal.
• Remove booster mounting nuts from inside of vehicle.
• Remove booster assembly and gasket.
• Reverse procedure to install, noting the following:
• Torque booster mounting nuts to 27 ft. lbs.
• Torque master cylinder retaining nuts to 27 ft. lbs.
• Torque power steering hoses to booster n...