Hi Martin, we had the exact problem 3 years ago. After trying to communicate with Opacmare for over a month we gave up and took it apart ourselves. the problem was corrosion. This is a very heave piece of equipment! Conny constructed a tool himself to be able to take it apart, but I guess you can find such a tool at a well equipped tool shop. We did this at Spice Island Marina in Grenada. Conny donated the tool to Oscar, the mechanical manager at the yard.
Before taking it apart conny sprayed it with oil to dissolve the corrosion, days before trying to take it apart. It’s extremely important to clean it so you find the hole for the small Alan key that is the lock screw in the threading between the engine house and the ring you want to turn to take it apart. it was 4 people working together to take it apart because it was so stuck! Arm yourself with a big portion of patience:)))
when it was disassembled he cleaned it and he also drilled a hole from the side and put in a grease nipple.
If you want to discuss it more in detail please send a pm to us and we can have a video call, Conny is happy to share what he learned in the process with you.
finally I must make a comment on Opacmare. They where not helpful at all, they were not interested in sharing knowledge on how to repair the gangway they just wanted to sell us a new engine for 3000 euro! Conny managed to repair ours for 7 euro!!! but it was hard work.