Repair stuck/rattling W205 headrests
 

So the main dealers said my stuck and rattling headrest not covered under used car warranty, and I didn't cop it till over two weeks from sale. Also said they were sealed and not repairable. If I'm going to have to buy a replacement, then might as well have a go at fixing the broken one, so here goes.
With a pick tool I managed to extract the leather flap end which is pressed into the base between the bars at the front underside.

https://cimg6.ibsrv.net/gimg/www.mbw...9da75206d4.jpg
Front edge of base flap.

https://cimg0.ibsrv.net/gimg/www.mbw...0d4bf3484c.jpg
Peel back. Repeat for corner and side folds which are similarly pressed into the internal frame.

https://cimg8.ibsrv.net/gimg/www.mbw...40ef220d27.jpg
Pop out side button, use flat tool.

https://cimg9.ibsrv.net/gimg/www.mbw...1880f1e358.jpg
Slide the frame out of the cushion

https://cimg4.ibsrv.net/gimg/www.mbw...1c54a8cbd2.jpg
Remove two Torx screws, and split the case from the bottom, hinging on the top, there are two click fit catches in the middle down a recess on the other side, you might have to prise these a little.


https://cimg4.ibsrv.net/gimg/www.mbw...57a5bb458e.jpg
Bingo! Two loose springs and slides fell out, plus a few tiny bits of sheared plastic.


https://cimg0.ibsrv.net/gimg/www.mbw...7bf514a3fa.jpg
These it turns out are what retained the slides pressed against the springs under the bar. Not sure of its purpose, could be some kind of one use anti whiplash brake on the bars.


https://cimg0.ibsrv.net/gimg/www.mbw...5f80deb495.jpg
The plastic retaining lugs for this spring are also almost fully broken off, allowing the spring to rise up.

https://cimg1.ibsrv.net/gimg/www.mbw...36f35cd050.jpg
With the spring removed you can see the lug hooks hanging off.

https://cimg2.ibsrv.net/gimg/www.mbw...87864d485c.jpg
The small broken pieces came from here, which would retain the two slide pieces against spring pressure held in the area above against the round protrusion. The other end of the slide was also retained by even smaller pin size pieces of plastic moulded on that protrusion which had broken off.
These slide devices seem to rub against the bars as you move the headrest fore and aft. With the retainers broken, the slides seem to wedge the bars under pressure from the spring, which may fall out leaving the slide loose and rattling against the frame.
I've glued a small crossbar of wire to replace the other hinge spring retainers, and I think I'll just glue the two slides in position without the springs, whatever their function was is not clear, but I'm guessing some kind of whiplash inhibitor.


https://cimg3.ibsrv.net/gimg/www.mbw...102e3c25cc.jpg
Hinge spring retained by a piece of wire hot glued in place of broken lugs. The slides were glued in and the springs discarded.

https://cimg1.ibsrv.net/gimg/www.mbw...f1042a77c4.jpg
Reassemble, replace on seat and test.
https://cimg4.ibsrv.net/gimg/www.mbw...a3da003e4f.jpg
Slides forward and back perfectly, no rattles while driving.

Nice write up, I hope i don't need to do this repair one day.

How did u pop out the side buttons
 

How did u pop out the side button??

Use a flat stiff tool like a paint scraper or preferably plastic like a windscreen frost scraper, and wedge between the edge of the button insert and the leather, and prise outwards. The whole assembly will pop out with modest pressure. Work around it or if you have two pieces of flat plastic squeeze one in either side and lift. I used a pair of thin paint scrapers, being careful not to mark the leather.

Who knew a headrest would have all these plastic parts lol nice write up!

Thanks for the advise! I will try it someday!

So I wanted to give my contribution to the thread as well. May help others. First of all thanks for the original write-up very useful.

Both my headrests were rattling, with loose pieces inside. Car is C Class W205. I took out the driver's headrest fairly easily by sliding backrest back.

Then using flat wide screwdriver I carefully pushed the flaps out of the headrest cover back to reveal the inside plastic bit. There are 4 sides lets say, two shown below and two that open in the opposite direction
https://cimg1.ibsrv.net/gimg/www.mbw...10665912b9.jpg
Showing first two flaps removed

I couldn't pop out the side button as described above, so again very carefully using plastic flat tool i moved the leather and the foam over the side button so it could slide out with the rest of the headrest.

Then i pulled the plastic headrest from its cover carefully so that the side button would not rip the foam inside.

https://cimg8.ibsrv.net/gimg/www.mbw...c9d52e014e.jpg
Inside of the cover where the side button slipped out

Then unscrewed the two torx screws and voila the i side.

https://cimg8.ibsrv.net/gimg/www.mbw...74d2acc9a1.jpg
Two torx screws to unscrew. Pry open with flat screwdriver from the lower middle section

Loose plastic bits, two springs some broken bits.
https://cimg6.ibsrv.net/gimg/www.mbw...9761c58e08.jpg
https://cimg0.ibsrv.net/gimg/www.mbw...37e66c8c4b.jpg
https://cimg8.ibsrv.net/gimg/www.mbw...fcb0e51f13.jpg

I removed completely the broken small plastic bits and the single spring, and put back the two black covers with the two small springs.


https://cimg0.ibsrv.net/gimg/www.mbw...10ff8bee27.jpg
Plastic covers reinstalled with springs inside. Bit tricky to set them correctly but dooable. Finally i now removed the sidebutton, from the inside by using flat screwdriver.
https://cimg3.ibsrv.net/gimg/www.mbw...1f22fa7eac.jpg
Side button removed.

Put everything back. Works great, no noise etc.

Still not sure what this spring was used for.


https://cimg4.ibsrv.net/gimg/www.mbw...c6d0e900c2.jpg
Left over bits :)

The Lever spring is there to push the headrest back from the forward position when you press the button.
The little black bits help retain the coil springs against the black sliders, which appear to be some king of impact brake on the horizontal motion of the headrest. Can you still adjust your headrest fore and aft? Mine was jammed under pressure from one of these spring/slide assemblies, and without the small broken off pieces it was not possible to 'lock' them off the chrome bar under tension from the springs, so I left out the springs, and glued in the slider bars.

Nice

Thanks for the write up! Wasn’t able to pull the headrest completely out, so instead I worked on it while attached lol, removed all the bits and PCs, springs too, I put foam in between the metal rods so it wouldn’t shake/move. Rattle gone.

I coluldnt manage to open it. Is there any video showing how the opening is or can you post it?

Thank you

what I used was this video, it’s essentially the same thing. Pay attention to which flap to open first and which overlaps on what and reverse it back when reinstalling. GLHF!

I managed to find used headrest without rattling sound inside. How should I remove the old passenger headrest? Should I take off the back cover of the seat?

You should not have to remove the back of the seats. Just so you know, you need a special tool to do this and it's normal to break the back of the seat easily and it will cost you over $250-300 for a new back of the seat.
Just do what you see in the video and you can pull the headrest right out.. Some also have a lock on the headrest to stop if from being removed to far.