Adjusting Rack Damper Bolt

I know I need to adjust or replace the rack damper bolt on the fuel injection pump of my 1982 300 TDT because there is a terrible vibration at idle speed. I know where it is and the lock nut, etc. I
have already tried to adjust it, turning it inwards about half a turn, but it hasn't helped yet.
Does anyone have any experience with that?
Paul Fretheim
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
Add image file
Upload is a website by car enthusiasts for car enthusiasts. It is not affiliated with any of the car or spare part manufacturers or car dealers discussed here. All logos and trade names are the property of their respective owners.