I´m quite familiar with manual transmissions and I beleive that I can help in diagnosing Your problem. Lets start with some questions.
1) When You are in 2nd gear does it feel like the car wants to creep forward or not?
2) When shifting into 3rd is it only hard to engage or do You also have a scraping noise?
3) Do You have any gear jump-out problems when driving?
4) What gears were usable before You readjusted the linkage?
1984 500 SEL