just installed some new pads in the front. because i pushed the caliper pistons in, i know i need to pump the brakes a little for the calipers to push back out after installing the new pads. however, i did this while my engine was turned off. the brake pedal stiffened up but i noticed the pads did not get pushed against the discs. after starting the engine (turning "on" the car), the brake pedal was loose again and i pumped again. sure enough, calipers came out and the pads were pressed firmly against the discs. just wondering why the car needs to be turned on for this.. and, did i mess up anything by trying to pump the brakes while the car was off?

thx in advance

 

just finished my rear brakes today.. found a frickin SCREW (yes.. big *** screw, not nail) in my brand new yokohama es100s.. blahhhhhh

anyways... just wanted to check up on a reply and vent some frustration over that screw in my tire.. so... anyone know the answer to my original post?

THX in advance

 

The brakes use the engine to power the brakes, "power brakes". So with the engine on, you have alot more power to pump the brakes.

 

That's completely normal. Brake master cylinders are vacuum assisted. The vacuum is created off of some engine component, not sure which. When the vacuum isn't evident, fluid pressure won't be created and the pads won't fully clamp the rotors.

 

You didn't mess anything up. Are the breaks stopping normally? They will be fine after seating.