Clutch to the floor???

2002 jetta tdi. I did the brake booster. The thing is the car sat for a while. Now it's leaking fluid where the fluid line goes into the slave cylinder and the clutch just goes to the floor and stays. Appears to be leaking right at what seems to be a plastic piece the fluid line goes into. Right next to the bleeder. Can a slave cylinder go bad while sitting 5 months?? Can I just repair that connection.??

If that is your problem, here is a seal kit for both ends of the clutch slave line.
https://www.idparts.com/clutch-hydraulic-line-ring-seal-set-all-vw-manual-p-2114.html

It was the o ring

So it's clear what to do with the o ring. But what the heck do you do with the little black grommet they send. The only thing I can think of is it sets down into the clutch slave. If that's the case it has to come out. Because my fingers won't do it.

If I can recall correctly, I put the grommet on the clutch master end of the line. Yup, it requires long, long nose pliers to get it oriented with the master in place and the master needs to be mounted before installing the line.

My seal kit had two of each seal type. There may be different styles depending on the fitting on the cylinders.
I used the grommet on the master end and the o-ring on the slave end of the line.