|
Took delivery of a 5000 mile Passat TDI Sport a week or so ago, first registered in September 2001, and am now wondering if there's a problem with the brakes. Difficult to describe, but here goes! When braking, say, to come to a stop, a 'pulsing' can be felt through the brake pedal and throughout the car. It's like a very 'watered down' version of the ABS working but all I'm doing is normal braking; it does it whether stopping from speed or just going around town. Had a '99 1.8T Passat beforehand and never experienced this. Apologies for a vague description but anyone got any ideas?
|
|
First suspect distorted disc(s) Prime cause is heavy braking followed by holding the car on the footbrake say when you come off a motorway. Other possibilities include damaged/distorted tyre.
|
|
|
Could be a brake disc running 'out-of-true' beyond the allowable limits. Possibly even a sticky caliper piston.
The very slight out-of-trueness of a disc will normally push back the piston when the brakes are off until there is virtually no pressure from the brake pad (friction pad) on the disc, but a sticky piston may resist this backing off and will rub the disc once or twice every revolution. This can lead to overheating of the piston which makes it expand and stick even more firmly. Sometimes the vibration does not show up until the car has travelled, say, 20 miles and the brakes are starting to get warm.
A sticky piston is sometimes caused by the rubber dust/water cover not being fitted correctly. The cover usually fits into a groove in the piston but may have pulled or slipped out, allowing water to enter between the piston and the caliper bore.
Lightly rusted caliper pistons will usually clean with some fine steel wool soaked in brake fluid because the piston surface is very hard. Also, it is usually found that some light pitting is of no harm even though it looks as though it would wear or tear the rubber sealing rings.
Hope something here helps someone even if it doesn't answer Gordon's problem.
|
Here's a tip that I forgot to mention ....
If you feel the wheels after a short journey and one is warmer than its opposite partner, it is most likely that the brake on the warmer wheel has been binding.
|
|
|
|
