W124 300 CE Front seats not locking in place

[Clark300CE]

Hi,
I'm in the middle of working through a list to get the car MOT'd and it was pointed out to me today that both of the front seats upright lumbar sections don't do not lock in place. The car has electric seat controls and every other part moves correctly. The seat bolsters nove forwards and backwards, even the headrest moves up and down but the lumbar section does not lock.
Is there a silly simple solution or will this involve lots of expletives and cash?? Help please.

 

[Scott_F]

From memory the seats lock with the ignition on or possibly with the gear selector in Drive.

 

[Clark300CE]

First thing in the morning I'm going to check.

 

[WDB124066]

Under front center of the seat base cushion is valve with a vacuum line from the floor going to it, check that vacuum connection is good. The output of that pulls a small cable each side of the seat back hinge that connect to hooks that rotate over the lock pin.

You may have to take the plastic off the sides of the seat to be able to see if the hooks are rotating.

So, two things to check first, the vacuum line from the floor to the center underside of the seat is in place, and if it is do the hooks rotate into position to lock the seat

 

[coupe addict]

Under front center of the seat base cushion is valve with a vacuum line from the floor going to it, check that vacuum connection is good. The output of that pulls a small cable each side of the seat back hinge that connect to hooks that rotate over the lock pin.

You may have to take the plastic off the sides of the seat to be able to see if the hooks are rotating.

So, two things to check first, the vacuum line from the floor to the center underside of the seat is in place, and if it is do the hooks rotate into position to lock the seat

Remember too that the seat backs unlock when their door is opened: most owners of coupes or cabriolets will have had to explain that to an MoT tester at some time. There's a good chance that you don't have a fault at all, just lack of familiarity.

 

[WDB124066]

Yes, and if it doesn't right away you can push the button on the seat back to relieve the vacuum to allow the back to tilt forward.

 

[Clark300CE]

Thank you gentlemen. The seats locked when the ignition was on. I wasn't familiar with this mode of operating on the car. I had a hunch that it might possibly be a quirk/idiosyncrasy of the model. One more think off the "to do list"
I have a mechanic with a high lift giving the car a pre MOT inspection for me this week, so I more than likely will be back for some very much appreciated advise. Thanks agin.

 

[HowardP]

I thought I had the same issue, but thankfully I read this thread first, so thank you all. I did also have a look in the Owner's Manual, and it's mentioned on Page 43.