Hi Guys, I need some advise here.
I have a 2008 Cooper S with 22500 miles on the clock. A few days ago I notice that after 8 hours (+/-) with the engine turned off when I try start it up the break pedal is really stiff, as soon as the engine starts the pedal becomes normal. Does anybody have a clue on the problem? My guess is that the vacuum system has a air leak but I cant imagine where. Thanks for your thoughts.

 

It's that how most cars work? Pump the brakes a few times with the engine off and it'll get stiff. The brake booster uses the vacuum created by the engine. No engine means no vacuum means no brake booster.

 

Pretty normal....
Most higher mile cars do EXACTLY this...
I would not spend one $$ chasing down a ghost...
Perhaps it held the vacume better/longer when newer (but given enough time to sit, it would STILL DO EXACTLY WHAT YOU DESCRIBE)....but if it is functionly OK, I'd live with it.

 

normal

 

Hypochondria :S

 

Just check your brake pedal, reach down and check it for fluid... sometimes... if the back seal expires it can allow brake fluid to seep down the activation rod into the booster and possible onto the activation rod connected to the pedal and in some extreme cases it can be seen dripping onto the floor mat.

This can also be the cause of the booster losing vacuum over several hours.

Motor on!

 

It's perfectly normal. And, what's on a car is a BRAKE pedal. Break is something different.