Hi folks, I have a 2000 Dodge Neon that on occasion, usually in the morning, that while backing up, the brakes act as though the the power booster has gone out. Meaning it is VERY hard to get the car to stop. This problem has never occured going forward, and always when the car is first started up (say first 45 seconds). This issue occurs at random, and is difficult to reproduce. What should I be looking at? Vacuum lines? I replaced from and rear pads and shoes about 4 months ago. Thanks for any insight!