What's causing our Opel Corsa's brakes to seize on?

I'm writing from Portugal where we are having some problems with the brakes on our Opel Corsa D 1.3 75cv CDTI. From time to time, when you put your foot on the brake pedal, it sinks almost to the floor but the car brakes normally. After this, the brakes are stuck on, the brake pedal is all the way up and very hard. By just touching the pedal you lock up the wheels. In some cases this has caused accidents.

I have found that at least 17 other owners faced the same problem. To be honest, the car in two years has been in the dealers seven weeks in total to fix problems under warranty. They replaced all the pedals but on the last Saturday it locked the wheels when I was parking the car. Do you have any other reports of this kind?

Asked on 25 July 2010 by Ricardo Ramalho

Answered by Honest John
This has a vacuum pump to build up the vacuum servo assistance to the brakes. I suspect it, or its pipe, or the servo itself has sprung a leak.
Similar questions
I own a 2004 Mercedes-Benz E220 CDi Classic. It has 130,000 miles on the clock. Just a couple of weeks ago, a warning appeared on the dash: ‘Service Brake! Visit Workshop'. I visited my regular Mercedes-Benz...
My daughter’s 2012 Skoda Citigo recently developed steering wheel judder when braking. She took it to a Skoda dealer who charged her £189 to replace pads and brake discs. The mechanic said that the discs...
I've just experienced a similar situation to RW in a 2010 Volkswagen Passat CC with under 30,000 miles. The pulsing vibration on braking was very bad indeed and had gradually worsened over time. The inner...
Related models
Solid and decently equipped. Reasonable handling and some frugal engines.