Clutch slave cylinder bleed screw

Replaced master and slave cylinders plus plastic line between them d/t clutch pedal going to floor with no slave cylinder engagement. Tried factory suggested method to bleed but have to pump pedal severa times before clutch operates. Have heard two different versions of purpose of what appears to be a bleeder screw on slave cylinder body, ie one person said it's not a bleed screw; another says it is-both work in transmission shops.
Does anyone know for a fact that the body screw is a bleeder screw?
Any suggestions for someone bleeding clutch lines and components theselves?
Thanks

You didn't say what his is on. But, on my 94 yes it is a bleed screw. It takes a while and an assistant to get it bled out. Pump 3 or 4 times and hold down pedal. Crack screw with allen wrench. Watch it dosn't run down your arm, use catch pan. You can get 3 tries before you need to refill resivour again. Watch moving things arround. Any pressure on slave or master will crack the plastic housing. Found this out first time I changed the starter.
You can hear the air popping when its escaping and the fluid will look a little milky. You will also be able to tell by peddal pressure. Clutch will engage close to floor and there is no adjustment.

It's a '94 K2500 6.5 TD with NV4500 transmission and newly placed solid flywheel. I can get the clutch to work by cycling the clutch pedal 4-5 times so I'm thinking there must be air in the system.
Guess I'll see if the neighbor can operate the cluch pedal while I watch for Air. Thanks

Yep what a5150nut said.

Mines the internal slave and took more clutch pumps to build pressure at first. After it was bled some it "recovered" quicker. It can be a pain to bleed clutches. On install of my new master at first I could see very tiny bubbles coming from the hole in the bottom of the resivor pumping the pedal. So the master can kind of bleed itself some but takes a while. It will probably get better over the first few days. Seemed it help me to bleed it rest for hours then rebleed it again. I think pumping the pedal all those times froths the fluid somewhat.

Reiterate keep an eye on resivor level. You'll have a heck of a time if are making progress and then suck some air with the master.

Get a big pump type oil can and a piece of plastic hose that fits the oil can and the bleed screw. Pump the fluid up from the slave cylinder into the master. Piece of cake!

I used the methods supplied and now have a air free line. Thanks, John