Disco pump took a poop.

I don't want to insult your intelligence but I have--more than once--failed to close the bleeder valve and convinced myself the damn thing was broke. Likewise, there have been a couple times it simply was not connected to the male probe on the rifle. When I first got it the bleeder tripped me up more than once.

Or you might have just got a bad pump. I fill my Disco to 2000 and Marauder to 3000---surely a hundred times or more for the two--and no problems. I think pumps are like that. It is sometimes a matter of luck.

I'd call your dealer. Good luck. 
 
SunOptics are the people that build the pump for Crossman...
I have spoken to them many times.....
When I called them they sent me two free complete rebuild kits.....
Orings take a beating in this pump... 
but still a good pump just be gentle with it and it Just needs to be rebuilt more often than most...

If you look online... you can rebuild the pump it is easy to do... 
Also you can find o-ring sizes online.... I ordered o-rings ... at www.orings.com
Get some plumbers grease from Home Depot for a few bucks...
You can save a lot of money doing it yourself...

Also I found that some of the threaded parts just come loose..... just take apart and tighten...
Most times it will be the main outside silver cylinder..... if it is the inner parts and rings look good all you have to do
is tighten the threaded parts..

I learned this by watching a you tube video on how to take it apart....