Brake booster is failing after use in traffic. The brake pedal slowly sinks and when lightly tapped, it slams to the floor. When this happens, a loud suction can be heard inside the car, and the brakes are applied fully. This usually happens after brakes are used some time, say in a traffic jam. There is a site, tdiclub.com, which has forums where many people talk about this problem on their 2002 model year VW Jetta. The danger is that the brakes come on fully, which startles not only the driver and passenger(s), but the vehicles that are following. This is an intermittent problem (brake booster failure) but can be replicated if the brakes are used heavily. When the problem starts to happen, it will continue until the brakes are not used for quite some time. Once this started happening today, virtually every other application of the brakes caused the symptoms above. This occurred about seven times this day. This has been happening intermittently for a few years.

- Auburn, MA, USA