Chevrolet Full Size Cars 1979-1989

Power Brake Booster



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Fig. Fig. 1 The master cylinder assembly must be either removed or repositioned in order to access the power brake booster

Many of the vehicles covered by this guide are equipped with a vacuum power brake system which utilizes a standard vacuum booster. The following procedure is for removal and installation of a standard vacuum booster. A few vehicles may be equipped with a Hydro-Boost system instead of a vacuum booster. If equipped with a Hydro-Boost system, please refer to the procedure later in this section for booster service.

  1. Disconnect the vacuum hose from the vacuum check valve.
  3. Unbolt the master cylinder and carefully position it aside without disconnecting the hydraulic lines.

If sufficient booster clearance cannot be obtained, it will be necessary to disconnect the hydraulic lines from the master cylinder, then remove the master cylinder assembly from the vehicle.

  1. Disconnect the pushrod at the brake pedal assembly.

Some brake boosters may be held on with sealant, this can be easily cleaned from the mating surface using tar remover.

  1. Remove the booster-to-cowl nuts and lockwashers, then lift the booster from the engine compartment.

To install:

  1. Place the booster loosely into position, then connect the pushrod at the brake pedal assembly. If necessary, thread the booster retaining nuts on the ends of the studs in order to hold the booster while connecting the pushrod.
  3. Install and tighten the booster-to-cowl retaining nuts to 28 ft. lbs. (38 Nm).
  5. Reposition and secure the master cylinder by tightening the nuts to 22 ft. lbs. (30 Nm).
  7. If the hydraulic lines were disconnected, install and tighten the fittings, then properly bleed the hydraulic brake system before attempting to move the vehicle.

Make sure to check the operation of the stop lights. Allow the engine vacuum to build before applying the brakes.