Leak test
Note: ABS type is shown, standard type is brake, (9-inch power brakes) symmetrical.
1. Disconnect the brake booster hose from the brake booster, and connect a hose of the appropriate diameter to the brake booster.
2. Install a vacuum gauge between the brake booster vacuum hose and the hose.
Note: The brake booster vacuum hose has a built-in delay adjustment valve.
3. Start the engine, adjust the engine speed with the gas pedal so that the vacuum gauge readings are 40.0-66.7 kPa (300-500 mm R.S.), then stop the engine.
4. Check the vacuum gauge readings.
If the pressure gauge readings decrease to 2.7 kPa (20 mm R.S.) or more after 30 seconds, check the following parts for leaks:
- Regulating valve
- Vacuum hose, tube
- Seals
- Brake booster
- Master brake cylinder
Caution: Do not attempt to disassemble the brake booster. Replace the brake booster as a single unit.
Functional check
1. Install the vacuum gauge in the same way as for leak testing.
2. Connect the oil pressure gauges to the master cylinder using pressure sensor adapters as shown.
3. Release air through the valves
4. Start the engine.
5. Press the brake pedal with a force of 196 N (20 kgf). The following pressures should be shown on the pressure gauges at each vacuum value.
Note: The master cylinder size can be determined by the 15/16, 7/8 or 13/16 stamps on the master cylinder body.
Cars with ABS: 7" + 8" brake booster.
For 14" and 15" Wheels (Brake master cylinder ID. 15/16)
For 13" wheel rims (master brake cylinder, ID 7/8)
Cars without ABS (standard brake): 9" brake booster
For 14" Wheels: (master brake cylinder ID. 7/8)
For 13" wheel rims (master brake cylinder ID. 13/16)
6. Inspect the master cylinder for leaks if readings are not within the limits specified above.
Checking the delay valve.
1. Disconnect the booster vacuum hose.
2. Start the engine and let it run at idle speed. There should be vacuum. If there is no vacuum, the delay valve is not working properly. Replace the brake booster vacuum hose and check again.
[You will find the original on the portal hondabook]