- Disconnect the negative battery cable. Firmly, set the parking brake and block the wheels.
- Disconnect the vacuum hose to the vacuum booster.
- Disconnect and plug the brake fluid lines at the master cylinder. Place rags under the master cylinder to catch any leaking fluid.
Be careful not to spill any brake fluid on any painted surface. Permanent damage to the paint will result.
- Inside the vehicle, remove the snapring from the clevis pin and separate the clevis pin from the brake pedal.
- Remove the vacuum booster mounting nuts at the firewall and lift out the power unit and master cylinder/reservoir as an assembly.
- Before installing power brake booster, check the distance from the flange face of the booster to the end of the push rod. Projection should be 18.018.2mm (0.7090.717in.) for Isuzu trucks and RWD Impulse; 18.6mm (0.733in.) for RWD I-Mark.
- The procedure for measuring projection for front wheel drive vehicles involves the use of a push rod gauge (tool J34873).
- Set the push rod gauge on the master cylinder and lower the pin until its tip slightly touches the piston.
- Turn the gauge upside down and set it on the power brake booster.
- Adjust the push rod length until the push rod lightly touches the pin head.
- Installation is the reverse of removal. Torque vacuum booster nuts to 14 ft. lbs.; master cylinder and brake line fittings to 12 ft. lbs.
- Bleed the master cylinder and brake system.