HOWTO : W212 Rear Bench Swap (Integrated Child Seats - option 248)

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ptruman

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No longer a Merc!
Hi all

Did this today in a delayed lunch hour.

Car MY
2010 W212 E350

What did I do?
Swapped the rear bench seat in my E350 from a normal bench seat to one with IKS (Integrated Kinder Sitze) - Integrated Child Seats. This is fitting Mercedes option code 248 to your car.

How long did it take?
30 minutes

What do you need?
You will need:
Note: The rear base unit can be a bugger to find - they don't seem to sell many in the UK market, so mine came from Germany.

You will need to search for either A2129201450 or A2129200350 which is technically the "cushion" but you'll probably find it that way. You'll also need to get one in the right colour - I couldn't find actual black anthracite leather, so had to pick black anthracite "artico" leather - but it works.

Alternately, try searching for the seat material cover - as some people sell on the first part number they see...so A2129209633/A2129207737 (both Artico Leather) or A2129209733/A2129207837 (both Leather) or A2129209633/A2129207737 (both "Sport fabric").
Full seat part numbers can be found here...

How do you do it?

1) Remove the original bench seat
Imagine if you were sitting in the left or right seats. Put your hands in between your legs and reach down to the bottom of the seat cushion by your knees. There is a clip here, on both left & right sides. Get off the seat, and pull up sharply at these points, with both hands. The seat will unclip.
You MAY need to lift the front of the seat up a little, then push the seat back off two metal clips at the rear of the seat, but I didn't - those clips are used for the replacement.

2) Fit the rivet bolts
Either side of the clip receiver which is mounted into the metal bodywork, are two holes, which are exactly the right diameter to drop in your M6x14.5mm rivet bolts. Screw a rivet bolt into your setting tool, and put it in the hole and squeeze until fitted. Repeat until all four holes are filled with the bolts.

3) Fit the new seat
If not already removed, remove the plastic foot base from each child seat (this just needs two pressure clips to be pressed in, then the rest can be pulled forward and up to remove).

Look under the new bench seat and you'll see two metal catches that will latch onto the metal clips that protrude from the bodywork under the bench seat.

Keeping the front of the new bench seat slightly raised, put the rear new seat toward/under the ISOFIX bar, and push in *hard*. Lower the front of the bench seat and you should find your rivet bolts visible through two of the four holes under each child seat. If not, you need to keep pushing backward!

Put a washer on one of the M6x20mm bolts and loosely screw it in to a rivet bolt. Repeat with 3 more M6x20mm bolts so each rivet nut has a bolt in - and you know the seat is centered.

Tighten your bolts!

Then replace the plastic footrests but lowering them into place, and sliding them backward, keeping the back of the footrest pressed down to ensure the slide catches go into place. You'll hear the pressure clips "ping" when they locate.

You are done!

Basically the steps shown in (3) above are documented in this PDF - 2nd page, simply reverse the instructions to fit!

How do they work?
Each seat has a handle on the front. You pull it to release the seat. Each seat is spring loaded so will rise up and backward - you just need to push it back into place and it will lock.

To put it back, you pull the handle again, and pull it forward, then give a firm shove down at the front and back of the child seat, and it will lock into place.

What does it look like?

Seats down...(invisible child seats)
IMG_20171212_145604.jpg

1 seat up!
IMG_20171212_145808.jpg

Both seats up!
IMG_20171212_145815.jpg

How much did that cost?!

  • £67.23 - IKS Rear Bench
  • £46.62 - Postage of the IKS from Germany
  • £ 2.30 - 10 x M6x14.5mm Rivet nuts
  • £ 2.18 - 10 x M6x20mm bolts
  • £25.57 - Rivet nut setting tool
Total cost - £143.90 - although I'd argue the rivet nut setting tool could be borrowed, if you had a suitable tool equipped friend!

I've also got the corresponding headrest/bolster coming tomorrow - which was £9, but then an additional £20 in postage....

Why not buy a child seat?!
This is cheaper than a "top range" child seat - and looks better. It also won't leave pressure indent marks all over the seat like a normal ISOFIX child seat would - and can be sold with the car to improve value!

Hope you liked it!
 
That is very useful info, thanks. What are the part numbers for the headrest bolsters? If I can find the parts I’d like to do this as it’s a pain removing and storing the child seats when you need to carry adult passengers.
 
Will check and update, as hopefully the proper ones will be on the one I get tomorrow.

Annoyingly I've seen pictures pics of leather ones but never seen an actual leather one, so the one en route is fabric, but will advise tomorrow night :)
 
The part number for the headrest appears to be : A2059707050
eBay searching that brings up a fair few.

What I didn't know (but now do!) is that the clips to hold the headrest also have little red indicators that pop up if they are not clipped properly - so you get a warning. One of the ones on mine is a bit broken, but it moves a bit to give you the idea :)

Each "arm" has a guide for the seatbelt to go through, which doesn't seem to lower it much, but does ensure it's in the otherwise right place and can't go "in front" of the arm.

Shot "from the front" showing the headrest in place (yes, it's fabric, but it's not as hideous as velour...)
IMG_20171213_173643.jpg

Shot from the side - showing the comparison against the existing (normal) ISOFIX child seat.
IMG_20171213_173706.jpg

From "the book" - it states the seat should be used for children from 12.5kg to 36kg. Between 12.5 & 18kg you should also use the "additional padded table" - which I've not got - so probably need to re-weigh my child :) This also partially goes against the table below, which may also include height (check your groups!)

Merc also state:
Group 1 : 9-18kg - Folded seat MUST be out - Padded table MUST be installed, head restraint MUST be installed
Group 2 : 15-25kg - Folded seat MUST be out - Padded table MUST NOT be installed, head restraint MUST be installed
Group 3 : 22-36kg - Folded seat MUST be out - Padded table MUST NOT be installed, head restraint is OPTIONAL
 
Last edited:
Wow what a detailed and well written write up. Excellent!
 
Very minor update - I found a pic I actually did take when prepping for the switch.

This is a view "above" (top down) the rear right passenger seat.
The green circle shows the position of the "clip receiver" for the wire clip that is on the normal bench seat (i.e. the one you have to "pull up sharply"). The red circles are the holes you need you fill with the M6x14.5mm Rivet Bolts. The left side of the car is identical.

IMG_20171129_143728.jpg
 
Good article OP, cheers.

And I am surprised at the cost, thought it would be way more expensive.
 
Cheers. eBay stalking is the key. There is a German "local" eBay site where they don't list shipping, but you can haggle :). Also, it took me a month to see a complete piece as two I saw had tears and no foot steps.

Local eBay Kleinanzeigen
 
Well done on this very useful guide...
Question: did they ever make these in beige leather? Been looking on Herman eBay but only ever seen black... wondering whether a trimmer or even diy bodger could use the covering off my beige seat + some more material and make a beige one that looks passable....
I actually only need the iks bit on one side do they come apart? Cheers
 
All the seat options are in the linked PDFs. There are several Nappa leathers, but you'd have to ask Merc which part no was Beige :)
 
Also I think they do split on some cars, but not seen a split on a W212...
 
Cheers, here's the difference underneath, I reckon I could do it with my scalpel, needle and thread+ superglue... just need to get hold of one

 
You'd also need to replace the leather on the riser seat, which has a valance. Also, I'd advise against trying to get a single side unless you find a genuine one as I suspect the structural integrity of a solid base goes toward safety - there is no middle clip that I saw, just left and right.

Buy a double, try and reupholster, and just use one side. :)
 
I finally tracked one of these seats down on eBay and I probably paid a little over the odds, but they seem quite rare so I'm happy!

I'm going to give it a go over the next week or so once I get the parts and will report back!

This is a great tutorial, so thank you so much!

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Oh dear - my seats doesn't sound as straight forward as originally mentioned. I'm seeing four bolts underneath the seat, but there is an extra part I wasn't expecting...

Does anyone have any advice? Could I still make this fit?
05b417fc2e63a0c749622025f435dcef.jpg


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Are you driving an Estate? Those look like flip down seats ala the W169 A Class, not the W212, unless the new shape W212 has those. MY2009 to 2012 W212 at least should be rip/replace!
 
It's a 2005 E55 with split rear seats that fold down

I've managed to take the seats out, but cant see how to remove the arms. I'm not sure they're going to fit without some serious modifications to my car but I'll have another check once it's a little brighter outside

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