Hi, hope you can help.

My girlfriends father recently bought a second-hand 1999 A4 Avant. He hasn't had the car long or done much mileage in it yet but the brakes are playing up.

After starting the car, the brake pedal is very stiff, almost like there's no servo assistance. A few sturdy pumps of the pedal after a short while seems to make the problem go away, only for it to resurface when you start the car the next time.

The servo has been replaced with a totally new unit but still no joy in curing the problem.

Does anyone have any solutions or suggestions as to what this could be? It's spoiling the enjoyment of a great car!

Thanks.