The other day I got in the car to go to work and while backing out of the driveway on the first press of the brake pedal, it went straight to the floor with very minimal actual braking. The second press, it got a little pressure, and the third it got better still. Now every time the car sits for a few hours the pedal has no pressure until you pump it once or twice. Once it has pressure, I can drive it and it keeps pressure, although the pedal is still a bit spongy. Does this sound like a bad master cylinder or possibly air in the lines somewhere?

 

Well, it's a lot easier to bleed your brakes than it is to change the M/C...so I'd start there just to be safe.

 

check your fluid level first. Then I would try bleeding them as stated above.

 

I replaced the master cylinder the other day, it was not that bad of a job actually. Other than the whole brake fluid EVERYWHERE thing, it was fairly simple and painless. A refurb unit was $67, so not bad on price either. The brake pedal seems quite a bit better now all the time. Much firmer, and so far no signs of problems.