Checking the brake booster (vacuum test) (Cooper Convertible)
WARNING: This page does not describe the selected car, but rather 6 other vehicles, including the 2021 MINI Cooper, 2020 MINI Cooper, 2019 MINI Cooper, 2018 MINI Cooper, and 2017 MINI Cooper. However, it is still accessible from the selected car via links, so may be relevant.
Special tools required:
- 343100
Preliminary work needed:
- If necessary, uncover brake booster
- Detach the vacuum hose from the brake booster. Install the vacuum tester 34 3 100 between the brake booster and the vacuum hose of the check valve.
- Start the engine.
- Check the build-up of the vacuum.
- Switch off engine.
- Set a vacuum of no more than 0.8 bar by pressing the brake pedal and wait for the value to stabilize.
- When the brake pedal is not depressed, the vacuum may drop by a maximum of 0.06 bar during a test period of 1 minute.
If the required values are not achieved:
- Replace the check valve
- Check the seal between the brake booster and the tandem brake master brake cylinder (sealing ring) for proper condition and correct sealing fit.
- If necessary, check the brake booster for leaks with a smoke tester
- If the setpoint values are not reached after another check, the brake booster must be replaced.