Highpark

So i used to be able to leave my Q5 parked for a week, hop in, press the brake ( it still had vacuum left in the brake booster) start up and drive away.

This week I had the brake fluid changed ( I know they don't touch the vacuum system to do this), but now after sitting for just 5 hours, the brake pedal is stiff as a rock... there is no vacuum assist left ( of course its perfectly fine a second after starting the vehicle).

Audi says its normal. I say it wasn't "the" normal the day before i brought it in.

So... how long does it take your 2014 Q5 to loose vacuum assist when parked? How many hours or days of sitting before you come to a car with a hard brake pedal?

Cheers

motoguy128

Most cars I've owned hold vacuum for several days. An '06 BMW 325i I had would lose residual vacuum in a couple hours too.

Could be Bosch brake boosters and ABS systems are prone to this.... and Nissin and everyone elses are not.... haha.

Not sure why a brake flush would cause this. Usually it's a seal that's leaking or a leak on a vacuum hose. This is only on the manifold vacuum side, not hte brake side, so a flush should not have affected this. Maybe all the pumping to bleed it wore out a check valve or seal. Not sure.

Highpark

The dealer checked it out and said nothing wrong. id have to agree its ok.. just that it was better before their service.