patrikr

As of yesterday evening my brake pedal is really stiff until I turn on the ignition at which point of loosens up and feels normal again. This on a 4.2 which keyless entry, hence the need to press the brake pedal everytime. Is this normal or something I should have looked into?

Also got my first speeding ticket yesterday since arriving in CA two months ago. The Q7 is just too comfortable and steady at high speeds!!

AutoUnionQ7

How long have you had the car? With my experience of Mercedes Benz, the pedal loosens up over time

patrikr

Only had it for about two months and 2300 miles. What's wierd is that the pedal was normal up until yesterday evening.

AutoUnionQ7

Maybe call the dealer. Brakes/rotors are covered 12k miles / 1 yr

Jusforfun

I dont know how the Q7 system gets its assistance but that sounds like a typical vacuum servo air leak. IE without assistance the pedal is hard to push and does not travel as far.
Whatever system is in the Q7 seems to be loosing pressure or vacuum until the engine is running replenishing it, from what you say.
Either way its not typical of Q7 and should be looked into by Service.
The only other possiblity I can think of is if you were pressing or repressing the pedal a few times after the car was turned off thus using up reserve.
Be sure to let us know result thanks.

patrikr

Tried it again tonight and the pedal moves for about 0.5 inch and then "hits a wall", that's what it feels like.

And no, definately don't press the pedal after the ignition is off but that's what it feels like.

I'll try to go by Audi sometime this week to get it looked at. Will let you know what they say.

Jusforfun

Its been there overnight.
It took five pushes of the pedal before it went like yours (stiff and only moves about 1") I could also hear the air exhausting each time so definite servo leak at your end.

patrikr

Wierd, the last few days it's been back to normal. The car is at the dealership today as the AC doesn't cool and they'll take a look at the brakes too. Will report later today.

patrikr

So got the car back from the dealer and they didn't find any problems with the brakes. And as said, the problem had gone away by itself already. Wierd but will definitely keep an eye on it.

Jusforfun

Thanks for the update.