My understanding of a dash pot as it pertains to an automotive application is typically a spring loaded mechanical device that pushes or pulls an arm or linkage (e.g. carburetor choke pull off ect.) with an opposing force applied by vacuum or pressure. On the Mercedes the most common use of a “dash pot” that I have seen is in the climate control system for the vent door(s) controls.

A check valve is basically a vacuum delay valve that holds off vacuum or pressure for a calibrated pre determined amount of time and or lowers the amount of vacuum supplied to the component by reducing the size of the the orifice through which the vacuum passes.

A handheld vacuum pump tester with gauge is indispensable to check any vacuum related system.

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1982 MBZ 300SD Turbo Diesel- just turned 200,000- just breaking her in