Toyota 44610-17020 Booster Assembly, Brake

The brake booster unit requires no special maintenance apart from periodic inspection of the vacuum hose and the case. Dismantling of the power unit requires special tools and cannot be performed by the home mechanic; if a problem develops, it is recommended to use a new or factory rebuilt unit. Begin by removing the master cylinder and disconnecting the vacuum hose where it attaches to the brake booster using pliers to remove the hose clamp. From the passenger compartment, remove the instrument lower finish panel and air duct, then disconnect the brake pedal return spring and the push rod from the pedal arm. Unscrew the four retaining nuts and withdraw the booster unit from the luggage compartment. Installation is the reverse of the removal procedure, but before assembling the master cylinder to the booster, check the clearance between the back of the piston and the brake push rod. Using a depth micrometer or vernier caliper, measure the distance from the bottom of the piston bore to the master cylinder mounting flange and the distance from the end of the brake pushrod to the surface on the booster assembly that the master cylinder mounting flange contacts when installed. Subtract the two measurements to get the clearance; if it is more or less than specified, turn the adjusting screw on the end of the brake push rod until the clearance is within the specified limit, ensuring to lock the jam nut on the adjusting screw when the adjustment is completed. Upon installation, place the booster into position and tighten the retaining nuts, then connect the brake pedal, install the master cylinder and vacuum hose, and carefully test the operation of the brakes before placing the vehicle in normal operation.