Vacuum Brake Booster: Service and Repair

REMOVAL
1. Remove master cylinder assembly.
2. Disconnect brake vacuum hose from brake booster.
3. Remove all related brake pipes or clamps.





4. Disconnect push rod clevis from brake pedal arm.
5. Remove attaching nuts and then booster as shown.

CAUTION: Never disassemble brake booster. Disassembly will spoil its original function. If is found faulty, replace it with new one.

CLEARANCE BETWEEN BOOSTER PISTON ROD AND MASTER CYLINDER PISTON ADJUSTMENT





The length of booster piston rod is adjusted to provide specified clearance "a" between piston rod end and master cylinder piston.
^ Before measuring clearance, push piston rod several times so as to make sure reaction disc is in place.
^ Keep inside of booster at atmospheric pressure for measurement.
^ Remove piston (push) rod seal from booster, it equipped.

For vehicle without ABS





1. Set special tool (A) on master cylinder and push pin until contacts piston.
Special Tool (A): 09950-96010
Turn special tool upside down and place it on booster. Adjust booster piston rod length until rod end contacts pin head.
Special Tool (A): 09950-96010
Clearance "b": 0 mm (0 inch)

NOTE: Take measurement with booster set vertically or with supporting piston rod by special tool (09952-16010) so as to piston rod placed at the center.





2. Adjust clearance by turning adjusting screw of piston rod.
Special Tool (B): 09952-16010

For Vehicle Equipped with ABS





1. Remove piston rod seal from booster.
2. Measure depth of piston rod, i.e. distance between piston rod and mating surface of booster-to-master cylinder.
Depth of piston rod "c": 9.63 - 9.87 mm (0.38 - 0.39 inch)





3. If measurement is out of specified value, adjust depth by turning adjusting screw of piston rod.
Special Tool (C): 09952-16020

BOOSTER PUSH ROD CLEVIS ADJUSTMENT





Install push rod clevis so that measurement "a" is obtained and torque nut to specification.
Tightening Torque (a): 25 Nm (2.5 kg.m, 18.0 ft. lbs.)
Length "a": 114.5 - 115.5 mm (4.51 - 4.55 inch)

INSTALLATION





NOTE:
^ All brake fasteners are important attaching parts in that they could affect the performance of vital parts and systems, and/or could result in major repair expense. They must be replaced with one of same part number or with an equivalent part if replacement becomes necessary. Do not use a replacement part of lesser quality or substitute design. Torque values must be used as specified during reassembly to assure proper retention of all parts. There is to be no welding as it may result in extensive damage and weakening of the metal.
^ Check length of push rod clevis.
^ Before installing master cylinder, adjust booster piston rod.
^ Apply silicone grease to master cylinder piston.

1. Install booster to dash panel as shown. Then connect booster push rod clevis to pedal arm with clevis pin and clip.
2. Tighten booster attaching nuts to the specified torque.
Tightening Torque (a): 13 Nm (1.3 kg.m, 9.5 ft. lbs.)
3. Connect brake vacuum hose to brake booster.
4. Set push rod seal to master cylinder and set push rod sleeve to brake booster (if equipped). Install master cylinder.

CAUTION: Face flat part of push rod sleeve to seal side, or it may cause vacuum leak.

5. After installing, check (refer to BRAKE MASTER CYLINDER CHECK).