| The VW part that actually amplifies your foot pedal | | | | First in the testing process is to raise and support the |
| pressure is the VW brake boosters. As you step on | | | | front of the vehicle. Be sure one wheel will rotate |
| the pedal, the brake booster optimizes the | | | | freely. Start the car engine and allow vacuum to |
| performance of built-in assist, which effectively | | | | accumulate. Then, apply brake pedal several times. Be |
| multiplies the applied force to operate a vacuum | | | | sure wheel is free to rotate immediately after pedal is |
| through the rubber hose, which runs from the intake | | | | released. If brakes bind, it means the booster is faulty. |
| manifold. The brake booster increases the | | | | With the car engine is running, apply brake pedal |
| compression in the master cylinder to drive other | | | | several times and check operation of pedal. If |
| brake system components to come in contact with | | | | response is sluggish, then check the condition of |
| the brake discs and ensure stoppage. Backed by | | | | vacuum hoses and booster unit air filter. Allow vacuum |
| German precision engineering, brake boosters require | | | | to build up, then switch off engine and operate brake |
| built-in assist which you cannot find in drum brake | | | | pedal. |
| vehicles. | | | | Pedal should be vacuum assisted for approximately |
| There are cases when you have installed all brand | | | | three applications. Any less in applications will imply a |
| new pistons, seals, hoses and pads in all wheels and | | | | leaking vacuum system or an inoperative check valve. |
| also the hand brake. Then, after flushing the system | | | | Operate brake pedal several times to evacuate any |
| and putting in the recommended fluid and bleeding | | | | vacuum left in system with engine switched off. While |
| properly, you still get a very hard pedal and very poor | | | | maintaining light pressure on brake pedal, start the car |
| braking. You might suspect that the VW brake | | | | engine. If booster unit is operating correctly, pedal will |
| booster is not doing its job. Although when you pump | | | | fall under existing pressure. However, if pedal remains |
| the pedal a couple of times to expel the vacuum then | | | | stationary, it means there is a leak in the vacuum |
| put light pressure on the brake pedal with your foot | | | | system. |
| and start the engine, you can feel the pedal get not | | | | With engine running, apply and hold brake pedal. Then, |
| greatly pulled down. | | | | switch engine off. If pedal rises against foot pressure, it |
| The thing to do is to have full engine vacuum at the | | | | means the booster is faulty. |
| booster, about 18" of vacuum. Any less then that you | | | | Those mentioned tests on the vacuum system, |
| have in a vacuum can give a problem. Do some tests | | | | however, should only be performed if the hydraulic |
| and inspections. | | | | system is in satisfactory condition. |