Brake problem vw passat

phill106

My brakes keep locking on my car when i am driving. I have just abandoned my car in a hotel carpark!
What happens is i am driving, if i touch the brake pedal at all, it is rock hard and too sensitive, so i know it is going to happen.
I had it into vw garage a few months ago with same problem, they said it was the slide caliper on the rear, replaced that and the pads.
On thursday last week, it happened again, had to leave it in a shopping centre carpark. Had a look at the wheels and the pads are jammed against the discs. With the handbrake off, i couldnt even push the car an inch.
Just now i tried to park on a slope, no handbrake needed.
From previous experience, the car should be alright to drive again by tomorrow, but obviously something is seriously wrong.
Any ideas what?
its a 2002 vw passat tdi.
thanks


ps thank god for free hotel wifi

Mr Benevolent

Was the ABS light on? Could be the master cylinder, could be the ABS control module. Seems to be a common enough problem on the '01-'03 Passat.

crosshair1

very common problem on this car, blocked drains under windscreen allow water into brake servo when pedal is depressed. After a while prevents the master cylinder from returning fully and causes brake lock. the hard pedal you describe is part of the same problem as water may be drawn into the vacuum pump.
most garages should be aware of this problem

homer90

crosshair1 wrote: »

very common problem on this car, blocked drains under windscreen allow water into brake servo when pedal is depressed. After a while prevents the master cylinder from returning fully and causes brake lock. the hard pedal you describe is part of the same problem as water may be drawn into the vacuum pump.
most garages should be aware of this problem

+1
Likely scenario,

phill106

crosshair1 wrote: »

very common problem on this car, blocked drains under windscreen allow water into brake servo when pedal is depressed. After a while prevents the master cylinder from returning fully and causes brake lock. the hard pedal you describe is part of the same problem as water may be drawn into the vacuum pump.
most garages should be aware of this problem

thanks, would the master cylinder need to be replaced then, or is it just a matter of fixing the blocked drain?
Spent way too much fixing this car recently, so need to keep costs down!

crosshair1

Usually only the servo needs to be replaced, on some I've had to replace the tandem pump (diesel and vacuum) on the back of the head due to water being drawn through and dumped into the engine oil causing poor vacuum.
The cost of servo approx 280+vat, tandem pump is approx 400+vat from memory
worst case scenarion about €1k+vat, you may go for 2nd hand t.pump but for the servo you have to go new as this is such a common problem and cars in breakers yards usually have water in servo.
Regards