I adjusted my linkage on my 300CD first by loosening the nut retaining the horizontal rod that goes from the firewall to the vertical linkage at the injector pump. That simply provides more leverage to the pedal. Changing the upper threaded rod's length can sometimes alter shift points. Follow the rod from the pivot on the firewall to where it attaches to the pivot plate. Loosen that nut and move the pivot point out towards the left fender. The right red arrow in the prior posters picture points to the rod. Follow that rod to where it attaches to the pivot. I also rotated the linkage at the top of the valve cover to wide open, then clamped it there with small vise grips. Then I adjusted the vertical threaded rod behind the injector pump to reach the throttle stop on the pump itself. After those two adjustments I had NO slack or wasted motion from the pedal to the pump. I also used wheel bearing grease on all the pivot balls.

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81 300CD (sold) 1972 280 SEL 4.5 (sold) 1966 250 S 4 spd (sold) 1974 450 SL (sold) 86 BMW 325ES (sold), 1973 280C (sold) 1988 300 SE.