AnkitSaini

Hi Gurus,

I have a Q7 2007 3.0TDI UK import in New Zealand. My car brake padle sinks to the floor after driving around 120km. Happened twice, If i keep driving another 200km the brake doesn't workand Paddle goes all the way to floor.

Took it to mechanic , No Oil leak, Master cylinder replaced with second hand one, Brake servo tested and OK. No hot disc after padle sink , Brake pad are in good condition, Can't see any piston seize from outside. what the hack ...

I have only noticed the rear discs are bit low and may need replacement but that shouldn't let Brake padle to sink to the floor after 2 hour drive ?

Paddle comes back to normal after normal bleeding procedure and stay fine if I drive this car locally or don't go too far more than 100km.

Can someone please help !

Regards,
Ankit

J. Patterson

This IS an odd malfunction. One thing I WOULD suggest is that your mechanic check your wheel bearings for excess play. Excess play can allow runout of the rotor which pushes the pads back away from it. This will result in excessive pedal travel. Read up on "pad knock back"
Pad Knockback

AnkitSaini

Thanks mate, I will take my car to mechanic today and get that checked..