Brake Booster
NOTE:
Letters and numbers in parenthesis correspond to letters and numbers in illustrations.
- Reduce vacuum in brake booster by pressing brake pedal several times. Disconnect vacuum line (8) from brake booster (16). Install test connector (070) between brake booster and vacuum line. Connect vacuum tester (030) to test connector. See Fig 1 - Fig 3 .
- Raise and support vehicle. Remove left front wheel. Using appropriate fitting, connect brake pressure tester (051) to brake caliper bleed screw. See Fig 1 .
- Connect pedal force measuring instrument (060) at brake pedal.
- Start engine. Allow engine to generate a vacuum of 22-24 Hg (0.75- 0.80 bar) by snapping throttle open and releasing accelerator pedal. If a considerably lower vacuum is achieved or if vacuum decreases immediately, the "O" ring seal between brake booster and brake master cylinder may be damaged, or brake booster check valve may be defective. If problem is found replace "O" ring and/or check valve. See BRAKE MASTER CYLINDER under REMOVAL & INSTALLATION. If no problem is found, go to next step.
- Apply specified force to brake pedal and read off line pressure. See BRAKE PEDAL FORCE & BRAKE PRESSURE VALUE RANGE table. If value is within range, go to next step. If value is out of range, replace brake booster. See BRAKE BOOSTER under REMOVAL & INSTALLATION.
- Remove pedal force measuring instrument from brake pedal.
- Remove vacuum tester from brake booster.
- Remove pressure tester and connection fitting from brake caliper. Bleed brake system at caliper that was opened for testing purposes only. See BLEEDING PROCEDURE under BLEEDING BRAKE SYSTEM. Install wheel. Torque lug bolts to specification. See TORQUE SPECIFICATIONS .
BRAKE PEDAL FORCE & BRAKE PRESSURE VALUE RANGE
| Pound Force (N) At Brake Pedal | psi (bar) At Brake Pipe Line |
|---|---|
| 11.24 (50) | 131-290 (9-20) |
| 22.48 (100) | 522-696 (36-48) |
| 33.72 (150) |
769-986 (53-68) |
| 44.96 (200) | 1015-1233 (70-85) |
| 56.20 (250) | 1189-1392 (82-96) |