Master Cylinder Questions

I'm replacing the master cylinder on my '78 bus. I got the old one off and I'm trying to get the reservoir off the top of it to put on the new one, but it's not budging. It should just pop out, right? I really don't want to break this 35 year old piece of plastic. I've dowsed it with WD but it won't come off. Any tips?

 Success! I ended up cutting two pieces of 1"x 4" into wedges and notched them out, kinda like a ball joint tool. Then just tapped them in between the cylinder and the reservoir with a hammer until it popped off. There's some pretty aggressive barbs on the plastic tubes. I see why it was so hard to come off

Thanks for posting how you got it out.
KC