Inspection Using Simplified Tester
WARNING: This page is about a different car, the 2018 Mitsubishi Mirage G4. However, it is still accessible from the selected car via links, so may be relevant.
- Before starting this inspection, remove the brake booster check valve from the vehicle and check its operation (Refer to MASTER CYLINDER ASSEMBLY AND BRAKE BOOSTER ASSEMBLY ).
- Connect a vacuum gauge between the vacuum hose (incorporating the check valve) and the brake booster.
- Connect a pressure gauge and a pedal depression force gauge as shown. Air-bleed the pressure gauge and then follow the procedure below:
- Airtightness test with no load Start the engine, and stop it when the vacuum gauge indicator has reached approximately -67 kPa (-148 in Hg). The result is judged as "Good" when the drop of the vacuum approximately 15 seconds after the engine was stopped is within -3.3 kPa (-7 in Hg).
- Airtightness test with load Start the engine and depress the brake pedal with 200 N. Stop the engine when the vacuum gauge indicator reached approximately -67 kPa (-148 in Hg). The result is judged as "Good" when the drop of the vacuum approximately 15 seconds after the engine was stopped is within -3.3 kPa (-7 in Hg).
When one or more of the above check results are judged as "No Good," the vacuum hose or brake booster is suspected faulty.
- Brake booster characteristics test
Perform this test after the above (1) and (2) were performed.
- Non-servo effect test With the engine stopped, make sure that the vacuum gauge reading is 0 kPa (0 in Hg). Depress the brake pedal with 100 N (22.5 pounds) and 300 N (67.4 pounds), and measure the fluid pressure generated.
Standard value:
Item Pedal depression force 100 N (22.5 pounds) 300 N (67.4 pounds) Generated fluid pressure kPa (in Hg) 0 - 516 (0.0 - 74.8) 2, 080 - 2, 780 (301.7 - 403.2) - Servo effect test Start the engine. Depress the brake pedal with 100 N (22.5 pounds) and 300 N (67.4 pounds) when the vacuum gauge indicator reached approximately -67 kPa (-148 in Hg), and measure the fluid pressure generated.
Standard value:
Item Pedal depression force 100 N (22.5 pounds) 300 N (67.4 pounds) Generated fluid pressure kPa (in Hg) 4, 380 - 5, 780 (635.2 - 838.3) 9, 020 - 10, 420 (1, 308.2 - 1, 511.2)
- Non-servo effect test With the engine stopped, make sure that the vacuum gauge reading is 0 kPa (0 in Hg). Depress the brake pedal with 100 N (22.5 pounds) and 300 N (67.4 pounds), and measure the fluid pressure generated.