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W140 Rear Seatbelt Installation

6K views 15 replies 3 participants last post by  Joe-V12 
#1 ·
The passenger side rear seatbelt in my '97 W140 S500 sedan was somehow torn by the previous owner.

I ordered a replacement in the correct colour and I set out to replace it today.

Got the rear seat bottom and seat back out OK.
Got the side trim out OK.
Got the C-pillar cover out OK.
Got the old seat belt out OK, top and bottom mounts.
Got the NEW seat belt in the top mount OK, slipped it through the guide slot and got the C-pillar back into place.

The new seat belt will not release so I can thread it down the rest of the way to attach it at the bottom mount. I doubled checked the top mounting and it is lined up exactly. It can really only fit one way at the attachment point is notched to fit into the bottom of the seat belt reel unit. The bolthole is lined up exactly and torqued to spec.

Is there a trick to getting this to release? It is not the comfort-electric type so there are no other wires to plug in.

Any help would be appreciated, I haven not reassembled anything yet and am coming up inconclusive when searching this forum and elsewhere. No type of lock is mentioned in the EPC/WIS instructions?

Thanks!
 
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#2 · (Edited)
I had something similar if not exactly the same problem with another car I had changed the seatbelts .
When I installed them I couldn't pull the seatbelts out ,as if they were locked ,what I did is take them out again ,turn it upside down to release the lock and pull them completely out ,I reinstalled them fully extended then let go of the seatbelt ,worked perfectly .
There was a small pin on the edge of the base of the belt I found later that would have released the lock to extend the belts .
On the new seatbelt you have there ,did it come or have the little wire for the pretensioners explosive ( explosive ,lol) .:thumbsup:

Check this link out ,3rd post> http://www.benzworld.org/forums/w140-s-class/1303360-help-drivers-side-seatbelt-will-not.html

This post confirms why when I turned it upside down it released the belt >> http://www.mbca.org/forum/w140-rear-seat-belt-replacement
 
#3 ·
I checked those links, but those seem to be discussing the front seat belts which of a different design.

There are no pretensioners on these seat belts. They do not plug it into anything. A bolt in the top and a bottom is all that connects them to the car. Changing the position of the key in the ignition or pressing the seat belt release button changes nothing.

I tried your suggestion and removed the rear seat belt from the top mounting, flipped it upside down and all around and still could not get it to release.

I checked both the old and new ones carefully, there does not appear to be any type of release pin or latch?

I will post pictures shortly, but it's getting dark here now and I may put this off until tomorrow.
 
#4 ·
Day #2 and still no love from the seat belt.

I've scoured the this forum, the internet at large, and anything else I can get my hands on but still nothing seems to work.

Any hints guys?

It seems like this will be one of those simple things that after the "Ah-ha!" moment I will kick myself for a week about it being so simple.....
 
#5 · (Edited)
The seatbelt you have ,are there any holes on the sides were it would look like that you can insert a pin like toothpick or small nail/screwdriver to release the mechanism ?.
I had a look for some pictures on ebay what these belts look like ,all I can see is a small hole on the sides ,others do have the electric wire cap .
There has to be a release somewhere .:thumbsup:


Is yours like this one .
Mercedes Benz Seat Belt W140 Rear Left S420 S320 | eBay

Or this other one ?.
Mercedes S Class W140 Power Adjustable Driver Left Rear Seat Belt Buckle Latch | eBay

Have you try'd squeezing in were I added the red circle in the picture below ,just like the headrests when you need to remove them ,a hidden button .?
 

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#8 ·
OK, well that is definitely not a button of any type! I pushed harder on that than I have on pretty much any other part of any car ever.....there are also no other small holes for a pin or any other visible release point.

I tore apart the old one in an effort to understand what is going on here.

On the inside of that circled area is a small post that attaches to three other small plastic gears that act as a derailleur for the main reel. There is also the cup and ball with an arm mentioned in the previous links that act as a stop to the large geared wheel. Even with the ball and cup pushed into well beyond it's fully retracted position the reel still locks.

On the opposite side of the mechanism is a large flat wound steel spring, not much can be done with this.
 
#10 ·
OK, I've got the new one mounted in the car. It is bolted in the only way it fits so I do not think it is a positioning issue as in the first video. I will remove and remount to ensure.
 
#12 ·
This was listed as for the right right (passenger side). I actually double then triple checked with the seller who confirmed it was removed from the rear right (passenger side) of the donor car.
 
#15 ·
All that I know I have added here ,I've come to a stand still in front of a Wall regarding this fault here .
I think when the seller took them out of the car he just let them wind up all the way & it's now impossible to get them to retract unless someone opens them up to get to the release button inside .:thumbsup:
 
#16 ·
I have both LH and RH rears here out of the parts car. Both are not fully retracted as the belt coiled up interferes with the body and so reaches a point where approx. 1ft of belt is still out.

Very very finicky to get them on the correct angle to release but only took maybe 2 mins each maximum.
 
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