[thstone]

Just take the black cap off the reservoir - the purpose being just to release any back pressure when the fluid from the piston is pushed back up the line and into the reservoir.

The filtering thingy is hard to get out. Just leave it in there (along with the top portion of the reservoir). If you get close to overflowing the reservoir and need to remove some fluid, use a small tube or a straw and suck some out.