Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
Vacuum System, Checking: Notes
Special tools and workshop equipment required
- Brake Servo Tester: VAS6721
The following inspection instruction is for complaints about the brake booster or for a so called >>hard brake pedal<<. The inspection instruction serves as a guide and aid for an effective and objective fault finding.
The following components are included in the check:
- Brake Booster
- Gasket between the brake master cylinder and the brake booster
- Check Valve
- Vacuum hoses with connectors
- Vacuum pump (if equipped)
Keep the geographical surrounding in mind when evaluating the measurement results. The higher above sea level, the lower the air pressure.
Always observe all test requirements before checking the vacuum system:
- Visually inspect all of the vacuum hoses for damage (for example, tears or damage caused by animals) and secure fit
- Maintain clean working conditions when working on the vacuum system
- Clean the engine compartment before starting work, if necessary
NO RELATED
Use the Manual With the Right Hardware
Pair factory procedures with proven DIY tools so the instructions are easier to execute.
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.