Hydraulic cylinder replacement is pretty straight forward if you aren't all thumbs. Having a shop manual makes it a lot easier. I'd print the procedure, but they're copyrighted and I'm severely allergic to courtrooms and jail cells. If you don't have a shop manual, they're really worth the price and can pay for themselves with a single repair job.
1. Place the top in the stowed position.
2. Open the Bypass valve to equalize the supply and return side.
3. Cover the stowed top and nearby body panels.
4. Remove the spring clip from the lower cylinder retaining pin.
5. Remove the retaining pin.
6. Remove the upper cylinder retaining spring clip.
7. Slide the cylinder off the link.
8. Don't cycle the cylinder rod or you'll have a big mess on your hands . . and car.
9. Make sure the top hasn't been operated for at least five minutes and the ignition is OFF.
10. Unscrew the hydraulic reservoir filler plug.
11. Using a small, flat-bladed screwdriver, remove the retaining clip from one of the hydraulic lines on the cylinder.
12. Use a rag to clean up any leaking oil. Keep the removed line as high as possible. (You might want to have an assistant help with that part.)
13. Remove the hydraulic line's O-ring.
14. The replacement cylinders are pre-filled with oil, so you want to keep their plugs installed until it's time to connect the hydraulic lines. You'll need to order replacement clips and O-rings for the hydraulic lines. The lines press into place and the clips keep them there.
15. Repeat steps 11-14 for the other hydraulic line.
16. Install new O-rings on the hydraulic lines. Press each into the cylinder and re-install the (new) retaining clips.
17. Re-install the hydraulic oil reservoir plug.
18. Install the upper cylinder retaining clip.
19. Install the cylinder lower retaining pin and clip.
20. Turn the bypass clockwise.
21. Test the roof.
22. Enjoy a cold one - you earned it. Marvel at the labor rates you saved yourself!
23. Repeat step 22 as necessary.
CC