The trunk on my beloved 1985 300 TD suddenly refused to open. A local friendly mechanic gave the lock cylinder a whack and that fixed it...but it seems to also have ruined the cylinder which was not noticed at first. I have since: a) found the cylinder coming out of the casing; b) taking it out revealed a spring sticking out; c) a flashlight then showed a small ball still inside the casing. So... a) is the lock ruined? b) would reassemble of the spring/ball keep the cylinder in the casing? c) if yes to b), how the blazes to do that? Or plan z: look for a replacement (realize this implies a keying issue). If plan z: any part numbers? sources? (My searches have been futile!!)