Sat for a while, now air pressure doesn't build and brake beep inop?

[Tippyman]

I've got a 2000 AmTran, 72 passenger, FE bus, 215 hp DT466E, Allison 2000 push button trans, yadda yadda.

Worked fine before it sat for about 5 months. It starts up fine, but the air pressure won't go over 25 or so. Also, the beeping noise that the brakes make before a safe pressure is built up is very sporatic.

The beeping used to beep constantly until the pressure was high enough, but now you can tell it's trying to beep but sounds like a loose wire or something. It's like "b...bee.........beep........b..b.......bb......be ep..." Haha you get the idea.

Any ideas? I want to move my bus back to the garage for some work but can't.