I'm working through sorting some of the vacuum system on the $400 E300 I purchased. Has anyone every modified a vacuum system where you remove the door lock circuit from the system? How'd you do it? Right now the only thing receiving vacuum is the wastegate solenoid and the solenoid located on the drivers side, inner fender (impulse line to intake manifold). IIRC it is egr control. Way I'm running it right now is a y at the nipple in front of the brake booster that supplies vacuum to the two above listed devices. Now I want to pick up the circuit that supplies vacuum to the hvac system damper actuators. Where is the vacuum reservoir located? I called myself looking behind the plastic at the front passenger tire (external), wheel well area but did not see it there.

tia

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Jim

The 210 uses a different vacuum system than the older models.

There is an engine vacuum pump that feeds the brake booster, the EGR and wastegate transducers, and a feed to the cabin for the climate controls.

The pod on the drivers side is for the EGR and the pod on the passenger side is for the wastegate actuator. The two pods are the same part number so they can be swapped for troubleshooting purposes. The engine will throw codes if you just try to unhook the vacuum line to the EGR and it will run like a turd if you unhook the wastegate.

The PSE pump handles the door locks and pneumatic seats if you have them. Engine vacuum has nothing to do with the door locking system.

There is no vacuum reservoir in the system. The engine only needs vacuum for the two transducers and the brake booster. Shutoff is by an electrically operated valve on the side of the IP that interrupts fuel flow.

The PSE pump supplies vacuum (or pressure) on demand to operate the lock pods. The lock pods on a 210 are one chamber pods like a 124 and the PSE supplies either vacuum or pressure to lock or unlock. So there is no reservoir in the lock system either.

There is a feed line to the climate control from the PSE pump that is used if engine vacuum is unavailable. There are 2 check valves in the kick plate space on the passenger side that bring the engine feed and the PSE pump feed together for the climate control valve block located behind the dash.

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The OM 642/722.9 powered family
Still going strong
2014 ML350 Bluetec (wife's DD)
2013 E350 Bluetec (my DD)

both my kids cars went to junkyard in 2023
2008 ML320 CDI (Older son’s DD) fatal transmission failure, water soaked/fried rear SAM, numerous other issues, just too far gone to save (165k miles)
2008 E320 Bluetec (Younger son's DD) injector failed open and diluted oil with diesel, spun main bearings (240k miles)

1998 E300DT sold to TimFreeh
1987 300TD sold to vstech

Cool, I've got all that uncovered and have about got figured out what I'm going to do with it. I just want to get the center a/c vent to open.

thanks

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Jim

We're you able to get the center ac vents to work? I'm trying to chase down a vacuum leak in a 98 Mercedes E300 causing air to stop blowing from the center vents and moving to the defroster and two side vents after about 5 minutes.