As I recall, the seatback locks in my 92 300CE are vacuum operated and supposed to be activated while the car is running. I think buttons on the seatbacks release pressure to allow them to tilt forward. My problem is they stopped working and the seatbacks tilt forward anytime - both seats. Can anyone with a coupe offer some guidance on this problem? msaylor@redshift.com

There should be a blue vacuum hose underneath each seat.
If you have a vacuum pump to check the system, you can start by checking the complete system in the seats to see whether the lock and button in the seat itself function well or not...
If you want me to, I can mail you some pictures of this system in my 300CE conv. (currently there is no interior in the car and most of the systems are visible).

greetingz,

My car they lock fine.... but I suspect you have a vaccum problem like Mbenz suggested.

Look for the vaccuum lines under the seats and make sure they are not broken or disconnected.

Everything else is ok though right?

Door locks and all function properly?

IF you are having door lock probs too, then there is probably a vaccuum leak.

Thats my opinion on it.

Alon

seatback
 

Door, trunk and fuel filler locks work fine. Are the seats and locks connected to the same vaccum system? I'll check the lines first. Thanks!

i assume they are all connected tot he same pump, but have different lines that are color coded to different systems.

But I'm not a tech, so I don't know for sure. But it is what I think.

Alon

ssaylor,

The blue vacuum lines go to an electric controlled switch under the (left side of the) rear seats.
If this switch is broken, the seats will not be locked either (since you said both seats stopped locking simultaneously...).
This is easy to check (the rear seat can be taken out without any tools).

greetingz,

Seat Vaccum
 

Re: "The blue vacuum lines go to an electric controlled switch under the (left side of the) rear seats."

Could this switch be under the drivers seat in the coupe? I see the blue line under the drivers seat and it appears to terminate in a large rectangular box with a bunch of other cables. Looks like it has a black cover of some kind over it. I'll know more today. Thanks!

Another scenario
 

On my 300CE the drivers seat stays in the locked position all the time, vacuum or not. It will not release and is a pain to access the left rear seat if not impossible! Is the catch attached to the vacuum pot spring loaded to pull off when the vacuum disappears? If so, where is the spring located on the seat? This is what I suspect but without removing the seat, unable to see.

TIA
Tobias MB
4 MBs