Dick Clegg pellet pump.

I bought one of these pumps from ebay and it appears defective.

1. The pump has a layer of glue around the neck of the pump. - The
seller says they all have this.

2. The pump does not appear to suck air out of the pellets. - Am I
doing something wrong?

I put in some pellets, add water and pump the handle. I can feel air
coming out of the handle on the pull up but air seems to go back in
when it gets to the top and does not seem to form any form of vacum.

Any advice?
--
It will be a great day when our schools have
all the money they need and the Air Force
has to hold a car boot sale to buy a new bomber.