What is the Brake Vacuum Pump all about?

The brake booster is a device that helps enhance the effects of the hydraulic braking system in cars as a supplement to the primary braking mechanism. Each time you push the brake pedal, the force transfers to a rod. This rod passes through the brake booster and reaches the master cylinder. The pressure from the rod activates the master cylinder piston and works on the hydraulic braking systems.

The brake booster chamber contains a vacuum the engine creates. This chamber has two sections, separated vertically by way of a rubber diaphragm. When the brake pedal pushes the rod, a small amount of air is let into the chamber on the brake pedal side through a valve that also seals off the vacuum. This air pressure on one side of the diaphragm helps enhance the force of the brake.

However, in case of cars that have turbo charging or use diesel as fuel, the engine does not create the necessary vacuum. Thus, they need an additional brake booster vacuum pump to draw out the air and create the vacuum needed for the brake booster to function. Vehicles that typically run in locations of high altitude also need a brake booster vacuum pump.

The brake booster vacuum pump reduces dependency on the engine for the vacuum and can work independently of it. This device uses an electrical control circuit to work. It activates with a signal from the brake booster vacuum sensor that monitors the levels of the vacuum in the brake booster.

Keep in mind:

• The brake booster vacuum pump should be able to maintain up to 18” of vacuum for the brake booster to be effective.
• If you notice that the pedal has slipped to the floor of the car and you hear a hissing sound, this could be an indication of a leak in the air line or pump to the brake booster vacuum pump.

How it's done:

• The battery is disconnected. The faulty brake booster vacuum pump is located and identified. The vehicle is raised and supported on jack stands as needed. The engine under shield is removed for access.
• The brake booster vacuum pump hoses and electrical connector are disconnected. The brake booster vacuum pump is removed from the mounting bracket.
• The new brake booster vacuum pump is installed onto the mounting bracket. The hoses and electrical connector are installed to the new brake booster vacuum pump. The battery is reconnected.
• The brakes are tested for proper brake booster vacuum pump operation. The engine shield is reinstalled. The vehicle is removed from the jack stands.
• The vehicle is road tested and checked for proper brake booster vacuum pump and brakes operation.

Our recommendation:

If you notice the brakes are not responding as they should, book an appointment with one of our expert mechanics and have the brake booster system completely inspected. The mechanic will check the brake booster vacuum pump for damage and advise you if it needs replacing. Refer to the owner’s manual for recommendations on the frequency in which you must have the brake booster vacuum pump replaced.

What common symptoms indicate you may need to replace the Brake Vacuum Pump?

• Delayed brake response
• Excessive pressure is needed to make the brake respond
• A hissing sound when you press the brake pedal
• Brake pedal slips to the floor of the car when the engine is running and the car is stationary
• Braking becomes especially difficult in heavy traffic areas when the brakes need to be applied in quick succession

How important is this service?

A malfunctioning brake booster vacuum pump will not create the adequate vacuum needed for the brake boosters or power brakes to function. This undermines the effectiveness of your brakes and can be a safety hazard.