The dampers are considered sealed units and no fluid capacity specs are published because of that. Did you put the proper amount of ATF in the fork legs?
To drain and refill the damper cartridge itself, you'll need to remove the black plastic top (just threads out by turning counter-clockwise), remove the rubber bladder (carefully, so you don't puncture it), then turn the damper upside down over a measuring cup to see how much comes out. Normally, it's nowhere near enough and you'll have "dead" spots in the travel. It will take some experimentation to find the correct amount of oil to put back in. Push the damper rod the whole way in, pour fork oil (5w?) into the top where the bladder was and at the same time slowly pull the damper rod out to draw in the oil. Afterwards, you might be able to stick your finger down into the bladder recess to block the holes, then move the damper rod through it's travel. There should be no "dead" spots and any excess oil will be pushed out.
