Got a 99 Sunfire SE 2200 Manual Trans.

Over the past few months I have noticed my clutch pressure dropping down to useless....Issue is, fluid level is still full in the reservoir. If I crack the bleeder for a few seconds and close it back up, clutch is perfect again for about a week.

Someone mentioned there's an O-ring on the slave cylinder clutch lines, which is a part that only comes with the lines or with the slave (can't remember).

Is there anything else I can check before pulling the slave out. No visible leaks but obviously air is replacing the fluid currently in the slave.

Hopefully somebody has something.