...it's a bad start. The red rebound adjuster has no visible set screw (because there is no set screw), and when you pull it straight out you see this:
And then you can pull the lockout knob off and see this:
...which is a black plastic piece instead of a silver aluminum nut the same size. (If you remove the upper collar and pull that black nut off you can peer down into the fork and see the aluminum nut we can't replace.) These clues indicate that your Lefty is too old for us to fix.
Most of our customers who are still riding these forks will be faced with the tough choice of which modern Lefty to buy to replace their old fork. Which, if you divide the cost of a new Lefty over all the years they've been riding their old one, isn't as expensive as it first sounds.
