The switch over valve prevents over boosting by the turbo. I do not know it location on the w126. On the w123 it's at the 10 to 11 o'clock position when looking att he brake booster.

The bowden cable is an actual cable tha has a ball joint end at the top side of the engine. It does have a socket end to fit the linkage on top of the valve cover.

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RRGrassi


70's Southern Pacific #5608 Fairmont A-4 MOW car

13 VW JSW 2.0 TDI 193K, Tuned with DPF and EGR Delete.

91 W124 300D Turbo replaced, Pressure W/G actuator installed. 210K

90 Dodge D250 5.9 Cummins/5 speed. 400K