It looks like there's a snap ring inside where the notch is. Just looks like you just have to get the snap ring compressed and then get the cap out of the cylinder. Wasn't sure so that's why I asked if someone would know.If you look up my profile and email me a picture, i can hopefully give you details.
Some un-screw, sone have a wire, some have a retaining clip.
Glad you have a plan of attack to get it out. I had trouble pulling the gland out after removing the snap ring, i ended up using a bottle jack on the top of the cylinder and putting a bar through the eye of the cylinder, i used the jack to push on the bar, pulling the rod, gland and piston out of the bore.It looks like there's a snap ring inside where the notch is. Just looks like you just have to get the snap ring compressed and then get the cap out of the cylinder. Wasn't sure so that's why I asked if someone would know.