As far as adapting the vac/boost gauge, I don't see how it can work for what you're trying to monitor. For a vacuum gauge to monitor a filter, you would have to mount it between the suction side of the pump and the filter. Or, it may be mounted between the pressure side of the pump and the filter but it will only register pressure never swinging between both.

Also, to use that gauge to monitor a liquid, you'll need an isolator.

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-Evan


Benz Fleet:
1968 UNIMOG 404.114
1998 E300
2008 E63


Non-Benz Fleet:
1992 Aerostar
1993 MR2
2000 F250