Originally Posted by 97 SL320

[/COLOR]Do the brakes feel OK when you drive the car normally?

With the engine off, does the pedal fall _all the way_ to the floor?

Does the brake system warning light come on? ( This is the one that monitors front / rear brake pressure and triggers is one system does not make pressure, it may be integrated into the low fluid / parking brake on light, check your manual. ) If not light, the MC is likely OK.

If driving is OK and from what parts you changed, the pads need to wear in so they sit flat against the rotor. Due to a build up of tolerances, you are flexing the pads , caliper mounts , rotor. Without brake assist, you are unable to flex the system enough to generate a low pedal.

The test for internal master cylinder leakage is to lightly and slowly press the brake pedal and see if it sinks all the way to the floor. It also helps to modulate the pedal , down 1/4" up 1/8" down 1/4" when testing for a internally leaking MC. Bonus feature, drive on a slightly rough road, rest the foot on the pedal, with a bad MC you will feel the pedal fall away as you follow it down.

If the pedal is pressed rapidly, the MC cups flare out due to pressure , seal against the bore and pedal hold height.