Is the small vacuum pump under the rear seat the only source of vacuum or are the door locks connected to the supply out of the main vacuum pump?

Pump under rear seat is only source for the door locks.

Jim

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14 E250 BlueTEC black. 45k miles
95 E320 Cabriolet Emerald green 66k miles
94 E320 Cabriolet Emerald green 152k miles
85 300TD 4 spd man, euro bumpers and lights, 15" Pentas dark blue 274k miles

An engine vacuum line runs to the rear seat (left side) but that is for rear seat headrest retraction only.

__________________

"Buster" in the '95

Our all-Diesel family
1996 E300D (W210) . .338,000 miles Wife's car
2005 E320 CDI . . 113,000 miles My car
Santa Rosa population 176,762 (2022)
Total. . . . . . . . . . . . 627,762
"Oh lord won't you buy me a Mercedes Benz."
-- Janis Joplin, October 1, 1970

If he is using the TD correctly, then he doesn't have retractable headrests. Yep his profile says TDT (easy Jimmy). So no negative air to the headrests.

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1987 300TD 309, xxx 2.8.2014 10,000 mile OCI


Be careful of the toes you step on today, as they may be connected to the ass you have to kiss tomorrow. anonymous

“Be who you are and say what you feel, because those who mind don’t matter, and those who matter won’t mind.” Dr. Seuss

Having a bit of difficulty trying to pull the seat cushion- the locking mechanism not budging. What now?

Lift up on the black handle with one hand. With the other hand reach across the seat and pull up on the other side at the same time. Start on the passenger's side where you will only be lifting 1/3 instead of 2/3 on the driver's side.

__________________
1987 300TD 309, xxx 2.8.2014 10,000 mile OCI


Be careful of the toes you step on today, as they may be connected to the ass you have to kiss tomorrow. anonymous

“Be who you are and say what you feel, because those who mind don’t matter, and those who matter won’t mind.” Dr. Seuss

Passenger side is where the pump is IIRC.

In '87 there were two different pumps (early - late). The early one has a black lid on a black box, the late one has a gray-white lid on a black box. They're not interchangeable.

__________________

Gone to the dark side

- Jeff

The problem is that the latch does not release when the handle is pulled up. Works fine on the driver's side.

It feels like the pin that holds the seat is not being pulled back by the handle. Any suggestions?

I'll take a look at mine after dinner.

The black handle just pushes the pin out of the lock in the seat. If you look at the side that works you can see what I'm typing about. I would take a flat putty knife and slide it in there. That should release the pin and allow the seat to come up.

__________________
1987 300TD 309, xxx 2.8.2014 10,000 mile OCI


Be careful of the toes you step on today, as they may be connected to the ass you have to kiss tomorrow. anonymous

“Be who you are and say what you feel, because those who mind don’t matter, and those who matter won’t mind.” Dr. Seuss

Right on! Seat is up and out of the way! What next? Do I need to pull up all of the floor covering or go for the jagular and cut a slit in it? The pump is nowhere in sight...

It's in a foam block just under the sound-deadening blanket. I believe that the free side of the banket is the forward end, it pulls up without tearing/cutting. Lock/unlock the doors and you should hear the pump run.

__________________

Gone to the dark side

- Jeff

There must be more than one design - my car has the same carpet under the seats as the througout. Had no more time or patience so I cut out a flap of carpet right were I thought the pump would be and... there it was! Wrapped in foam and new looking. The one line coming out of it was tested and holds vacuum. When I tried to pull vacuum on the nipple of the pump itself, it would not hold. Am I wrong or the pump is no good?

If I understand the operation, the pump is capable of producing pressure as well as vacuum. It locks and unlocks the various door locks in the car depending on whether it "sucks or blows." The two front doors and the tailgate key locks have electrical switches attached that turn on the pump. I suppose the pump runs forwards or backwards. My copy of the diagram for the 1987 300TD shows only one air line going to each lock actuator. So the pump is not just a "vacuum pump." It is a vacuum/pressure pump. Mercedes calls it a "supply pump."

So I don't know if your test ("pump won't hold vacuum") means anything. I'll see if I can find time to test my pump tomorrow or maybe someone has a spare on their shelf.

Jeremy

__________________

"Buster" in the '95

Our all-Diesel family
1996 E300D (W210) . .338,000 miles Wife's car
2005 E320 CDI . . 113,000 miles My car
Santa Rosa population 176,762 (2022)
Total. . . . . . . . . . . . 627,762
"Oh lord won't you buy me a Mercedes Benz."
-- Janis Joplin, October 1, 1970

Lock and unlock the doors, see if it sucks and blows. If it doesn't even run, whether it holds vacuum/pressure is academic.

__________________

Gone to the dark side

- Jeff