Our latest featured repair is Power Brake Booster Replacement on a 2004 VW TDI Jetta, brought to us by a client from Coquitlam, BC.
Most vehicles use a vacuum operated booster to provide the easy brake pedal effort that we get with our vehicles. The VW TDI Jetta uses this system, however there is one twist: because this is a diesel engine the vacuum for the booster is provided by an engine driven vacuum pump.
Our client’s TDI Jetta was suffering from a very hard brake pedal and poor vehicle stopping. It required a very hard push of the pedal to slow down his vehicle. After diagnosing the system it was found that the brake booster was defective. After replacement power brake operation was fully restored and he was able to stop the vehicle with minimal pushing on the brake pedal.
Power brake booster failure is fairly rare, we do not change them often.
Besides the vacuum booster there are other methods to providing power brake boost. The most common is the hydroboost system which utilizes the power steering pump and an actuator unit between the brake pedal and master cylinder. Another rare and expensive method is found on some models of ABS brakes: it is an integrated master cylinder with electric pump providing boost.
The vacuum system is most popular due to the enormous amount of vacuum generated when a gasoline engine is running. This provides an easy free source of energy for the booster. A diesel engine requires a vacuum pump because it creates no vacuum.
Hydroboost systems work very well and are extremely reliable however they have one drawback: once the engine shuts off there is no brake boost. This can be very dangerous if the engine stalls. Vacuum boosters, by their design hold reserve vacuum which usually allows about three brake pedal applications after the engine shuts off.
The VW TDI Jetta is a very popular diesel vehicle for many reasons: it is well priced; it is highly reliable; it is very fuel efficient; it is smooth, quiet and powerful. Volkswagen has continuously offered diesel vehicles in the North American market since the 1970s. Mercedes is the only other manufacturer to have done the same. Diesel is popular in Europe (and many other parts of the world) and the European car makers have been and are diesel car leaders.
For more about your vehicle’s braking system click here http://en.wikipedia.org/wiki/Hydraulic_brake
For more about the VW TDI engine click here http://en.wikipedia.org/wiki/VW_TDI