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Discussion Starter #1
How do the front seats work on the SEC to access the rear? Both mine just fold forward when you push them forward. Was thinking in the long term that may dangerous in an accident. There looks to be a button on the side how are they suppose to fold forward? What's the process?
 

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Discussion Starter #3
Do you have to do anything though to make it push forward? On mine I can just walk up and push it forward. I thought that would be dangerous in an accident. I was wondering whether you had to push the button on the side of the seat first. If you do mine must be disconnected
 

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When the car is energized, the vacuum system to the seats keeps them locked for such purposes. this is a coupe thing.
 

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Discussion Starter #5
Oh so there locked just when your moving. Either that or the vacuum had been disconnected on the seats
 

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Under the seat front (covered by a carpet trim piece visible when the seat bottom is fully back and up) is the seat harness connectors including the vac line to the seat.
When the car is running and vacuum is created to the seat it locks the seat back in place and pressing the side button in releases the vacuum in the line (like a tire valve does).
Often the line is not connected or there is a leak in the joiner.
Vac can be tested with a hand held mighty Vac tester or similar to create vacuum and see if it holds.
 

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Discussion Starter #7
Okay thanks.. I'll have a look tomorrow. The door locks/fuel cap central locking works so hopefully something has been disconnected.
 

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Okay thanks.. I'll have a look tomorrow. The door locks/fuel cap central locking works so hopefully something has been disconnected.
I think you'll be lucky if something is disconnected. More likely, as with my car, the vac motors that latch the seat back are bad. Still available but kind of pricey and you need two per seat.
 

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Keep in mind the seat belt is going to tension on the impact explosion and your forward movement will most likely break your collarbone, let alone the 29 year old airbag exploding shrapnel into your face and breaking your nose. We are in good shape, even if the vac seat lock isn't operational.
 

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So as said before, the seat back locks are vacuum operated. In the engine bay on the left side by the firewall, you will see two check valves. The vacuum that comes from the engine splits into two tubes on the coupe and goes to two check valves (CV's) one of those feeds I believe is blue and that goes under the seats and Y's in two, one to each seat. Under the seat it wye's again to each of the two bellows. Each bellow is attached to a metal hook that latches onto a bar on the seat back. When the motor is running and vacuum applied, the bellows retract and engage the hooks on the bar, keeping the seat back vertical in case of an accident. The seat backs are heavy and in a accident with a high G force, that weight is multiplied and can cause increased injuries as Louis said.

The button on the sides of the seat vent the vacuum in the lines in case the motor is running and you need to get in the back seat. To test if yours is working correctly, the motor should be running and try to move the seat back forward without pushing the button on the side of the seat. If the seats go forward, then you have a bad vacuum system. Start by making sure the CV's are good, they do go bad. Then make sure your Bellows are good, then finally the button.

The main problem with old Mercedes is that they were designed with vacuum actuated items like the seats and the A/C pods to move the vent doors. These pods or bellows have rubber diaphragms in them and they go bad over the years because the rubber dries out and loses its elasticity and hence seal.

You see this all over the car. In the AC system they move the air vents. In the fuel system there is a CV by the fuel tank that keeps fuel up in the Fuel Distributor for quick starting. If your Benz takes several cranks to start, that one is bad. Plus the ones in coupe seats.

So that's how you T/S the seat back system.

I have the EPC breakdown at home and if you want it, PM me.
 

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Discussion Starter #11
Okay sorry guys I didn't get an owners manual so not sure how some of this stuff works or how things operate but I'm getting there.

I've seen the metal hook now which isn't engaged with the engine running. If I press the button I'm sure I can hear a click somewhere under the dash? In another hour or so I'll go and check out the cv under the engine and pull the back of the seat and see what happens behind there.
 

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Discussion Starter #12
Is this the CV in the firewall you were referring too? The top too hoses feel stretched and basically just sit there the two vacuum hoses underneath are more snug fitting. The on the left split into 2 and the other picture is them disappearing into cabin. The blue one next door is a single tube that goes with the rest of the other group into a different section of the cabin. I can't run the engine at the moment because I don't have a radiator attached.
 

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Discussion Starter #14
Where do the rest of them go? Does one go to the economy gauge? The other one next to the blue one splits and then goes past the bonnet hinge and into cabin.
 

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I've seen the metal hook now which isn't engaged with the engine running.
Try with the engine running and the doors closed. I've recently tested mine and the doors certainly need to be closed to lock the seat backs.

I may even have had to buckle the seat belt but I can't remember tightly.

And, as someone said, one really does need the seat back to be locked in the event of an accident. Very bad news to find a heavy Mercedes seat back wanting to continue forwards at 60 mph when your seat belt is slowing you rapidly towards 0 mph.

RayH
 

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Discussion Starter #16
Yeah that's what I was worried about. I have found some weird stuff on this car. Like the door lights don't go off on either door on the light setting. Looks as though the switch wiring at the door doesn't look right which may affect the seat locks although the seat presenter works. May have all been a bi product of the seats being wired live? The lights have been removed out of the doors. The fan/radio and seats all work without the ignition on and key in. The air con compressor doesn't kick in but still trying to research that issue.
 
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