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Discussion Starter #1
Before I embark on this seemingly painful disassembly (https://w220.ee/WIS_91.16_Head-rest/Restraint) does anyone have tips, gotchas, or tricks to offer?
Given so many other plastic things on this vehicle seem to have brittled to the breaking point, I'm guessing the plastic vacuum actuator assembly has broken apart just like the front door lock ones have. I'm really starting to wonder if I'm going to have to fix/replace every one of them on the entire vehicle, or anything plastic that operates under load.
It's a damned shame, too, since most everything else on this car seems to be in near pristine condition!

Feeling down today...
 

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Hi,

Don't feel down, a few plastic Vac Actuators are really minor problems to have !!

You are of course quite correct, you do need to disassemble and verify the problem, also replace the faulty Part !!

All Cars suffer with brittle plastic bits as they get older, MB didn't patent the built in grief :grin

IIRC @cowboyt has done a complete shelf strip down, he put up a post somewhere about how to do it, perhaps he'll be along soon to advise where it is if you can't find it ................

Try "cowboyt trunk harness" in the Forum's Google search ;)

HTH,

Cheers Dave
 

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Discussion Starter #3
@Dave2302, much appreciated! You certainly do provide a lot of help on the forum! I'll search up and read through the post.
Regarding brittle, I've owned a lot of very diverse cars (Volvo, MB, VW, Lexus, BMW, Subaru, Saab, Honda, Toyota, Audi, Ford, Jeep, Mazda, Fiat, Chevy, Dodge, etc. Most all of them were in my care beyond 10 years of age. Yes, some had brittleness issues. But this particular S500 literally takes the cake! It's the most brittle of them all!
From what I could find out about it's history it's been here in southern Texas the whole time, with the last few years being in Louisiana. All very humid climates. Short of it being a manufacturing defect or specific toxic exposure issue, I'm at a bit of a loss as to why this particular one seems to be so much worse. If this were a wide-spread issue across a given make or model, it would basically make them throw away cars.
IMHO. :)
/EndRantHere
.....
Breathe in, breathe out...
 

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Discussion Starter #5
You should try owning one of the slightly older MB cars with the biodegradable wiring insulation...
LOL... No thanks! I already endured that pain when I had a 1983 Volvo Turbo. The engine wiring harness was French made and the insulation just crumbled off after it was about 10 years old. During the massive rebuild that ensued I basically hand re-built the majority of the vehicles electrical, wire by wire, connector to connector.
(I have actual photos of the rebuild, but not on this mobile that I'm replying from)
 

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Discussion Starter #6
Try "cowboyt trunk harness" in the Forum's Google search ;)

HTH,

Cheers Dave
Dave, I found the post. Lots of good intel in there. But the photos aren't showing up for me. I sent him a PM to ask if he still had them.
Your help (and everyone else's) is greatly appreciated.
 

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Hi 4DGeorge,

Responded to your PM; you're not the only one who's run into that. You might have a Web proxy, like I do at work, that blocks pixhost.to, which is where the images are hosted. You do *not* hgave to

Second, I just worked on the rear headrest for my S600 TT. Turns out the left rear one wouldn't go down. So, while I had the interior apart anyway (the right side interior got water in it due to that f****ng reed valve up front--since fixed), I worked on that as well. There's a PDF document that I used for doing this, done by @ricebubbles, the same guy who wrote that w220.ee document. It was a *BIG* help.

https://www.benzworld.org/forums/w220-s-class/1649587-rear-head-rest-will-not-lower-2.html#post10359081

If you heard a loud POP, then it sounds like the air bag that pushes up against the headrest actuator went kablooey. Not sure if those little air bags can be purchased separately.

One tip. That black part on the rear headrest actuator is the actual "actuator" part. It does pull out from the beige section--mine did so reasonably easily--and I had to do so in order to get the darn actuator assembly out. Then, I could use the air fitting tool and disconnect the air hose. In my case, the problem was that one of the hoses (the back one) wasn't plugged in quite all the way, so not enough air or vacuum was getting to the black actuator part to make the head rest move. Fixed now, and it works great. :)
 

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Discussion Starter #8
@cowboyt, thanks for the PM reply.
I got into the back of the trunk (because it was easy) and looked at the actuators for the headrests. The passenger side one has broken off, as suspected, and is sitting loose on the gas tank. I spent a few minutes trying to press in those black pieces to release the head rest. Also tried to see if there was anything I could move to manually lay the head rests back down. There's definitely a release mechanism, but I wasn't able to get both sides to let go. No joy.
I did go through the trunk lid and got those items pre-fixed. Much more solid sounding, no more rattles. Added a little sound deadening to it as well. Given shortness of time, I only did a partial treatment.
I'll go read to that PDF and see what I can learn.
Much appreciated.
 

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Hi Guys,

So are we saying you can change these Actuators from inside the Trunk, rather than removing Parcel Shelf trimmings inside the Car ??

Just want to know for future reference since I've never done the Job :wink

Cheers Dave
 

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Discussion Starter #10 (Edited)
@Dave2302, No, not suggesting that. I just wanted to get a quick look at what may or may not have been the issue.
But I will admit...the more I look at that gas tank the more I wonder just how easy it would be to remove it. It looks to only have a few bolts and connections to it. If it's already fairly low on fuel... it just might be the easier path.
...
Five minute later... I found these tank removal instructions:
https://mbworld.org/forums/attachments/s-class-w220/338853d1473074130-01-s600-drain-gas-tank-install-fuel-tank.pdf

I guess the question becomes: If I were to pull the tank, would there still be any reason to pull the interior out?
 

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Hi,

I would far rather remove the Interior parts than the Fuel Tank, there are so many pipes accessed from under the Car, and in UK at least I bet the large Pump Suction Feed Hose 90/12 will be seized in the Tank base thread solid :( Also very difficult to get at with Rear Sub-frame in the Car

But I've never done Head Restraint Actuators so :dunno:

The reason for my curiosity is that I have a Customers Car with one not working, and as we are gradually working on getting all his jobs done, that job is getting nearer the top of the list after each time his Car comes in !!

The thing with MB is it isn't always obvious how things come apart, but once you've removed "xyz" and found the hidden clips "abc" or whatever then you suddenly realise there was no need to remove "xyz" in the first place .................... I've played that MB game many a time :laugh

Terrell and his Trunk Harness is a good example of that game too :devil

Cheers Dave
 

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Having taken apart two interiors--one with the fancy moveable seats and one without--I think it's easier to just pull the seats and go that way.
 

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Discussion Starter #13
Having taken apart two interiors--one with the fancy moveable seats and one without--I think it's easier to just pull the seats and go that way.
I'm thinking the same at this point. The underside tank connections (which aren't readily visible) would likely make it a bigger hassle than I'd want.
But since you've pulled an interior with moveable seats, any pointers?
I am learning how MB has made a lot of things very easy to come apart, but only if you already know where the clips are and which way to move it.
 

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Oh, that's definitely true. It's easier, from my understanding, than previous models were.

If you've got the standard bench seats, it's very easy. There's a clip on each side, right about where the outside corner of the seat is. Just reach under there, and you'll feel it. Then, there are some bolts for the seat back--either two or three, I'm not recalling exactly--but it's at least two. Unbolt those, and then slide the seat back straight up. There are tabs on the seat back, close to the top, that slide into the sheet metal to hold it in place.

If it's the moveable seats, then it's a bit more complicated, but definitely doable. Each individual seat bottom has two latches. It's a tighter fit, but you can get your hand under there and get to 'em. It's like the bench seat bottom, but a pair for each seat. You don't have to disconnect the lumbar support control; with careful fiddling, you can fit it through the square "hole" and get it out. However, on the right side, I did disconnect one of the hoses from the lumbar dial controller; it was just so much easier. It simply slides off, with some effort, since it's a rubber hose coupling with no clamps. The seat mover thingamabob assembly is easy enough to unbolt. The seat backs are a bit different from the "vanilla" (if you can call an S-class "vanilla") rear seat back, though the concept is very similar...with one addition. The armrest assembly is held in by a couple of bolts at the top, and those same bolts hold the seat backs in as well, so yep, you're pulling out the armrest assembly. To do that, you'll need to pull the middle "seat". That can be tricky, but it's basically a click-snap-in sort of thing.
 

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Wow it took me longer to read the above posts than to remove the RL Head Rest Actuator. But then this is my third time at repairing the black hockey puck mechanism which has sprung a slight leak and will not generate enough force to lock the head rest in the up position. May have to buy a new one.
The trick to removing the head rest in the first instance is to look carefully with a mirror and bright light into the hole and identify the black retaining clips. Then using a 3mm wide screw driver apply downward pressure on the clip one at a time. It is also possible to lever the screw driver against the TOP edge of the opening thus pushing the clip down. At the same time push the chrome part of the head rest towards the back window. Check the photos in the w220.ee link above to see what the clips look like. Once you have done it once it is a piece of cake.
Be careful when removing the small electrical connector as this time mine broke. I am now in the process of soldering extension wires to the puck and adding my own two pin plug which will be easier to get at next time.
Best of luck,
Brian
 

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I revisited my writeup for removing and repairing a W220 Rear Head Rest Mechanism in the w220.ee Knowedge Base and have added extra photos and more detail in an attempt to make it is easier to understand. Having just removed the RL head rest mechanism for the third time I admit I had to look at the writeup to remember exactly what to do.

See here for the latest information. https://w220.ee/WIS_91.16_Head-rest/Restraint#DIY_Repair_Mechanism_-_Rear_Head-rest.2FRestraint

Now I need to get back to finishing fixing the leaking hockey puck when I would rather be installing my new media unit and my new Distronic. Fortunately I already had the rear seat out to install the cables for the media unit.
Brian
 

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Discussion Starter #17
I revisited my writeup for removing and repairing a W220 Rear Head Rest Mechanism in the w220.ee Knowedge Base and have added extra photos and more detail in an attempt to make it is easier to understand. Having just removed the RL head rest mechanism for the third time I admit I had to look at the writeup to remember exactly what to do.

See here for the latest information. https://w220.ee/WIS_91.16_Head-rest/Restraint#DIY_Repair_Mechanism_-_Rear_Head-rest.2FRestraint

Now I need to get back to finishing fixing the leaking hockey puck when I would rather be installing my new media unit and my new Distronic. Fortunately I already had the rear seat out to install the cables for the media unit.
Brian
Thank you for the additional details.
I didn't read any mention of how the mechanism releases the spring lock keeping the headrests in the upright position.
Once I get mine removed from the vehicle, I'm going to figure out someway to add an emergency pull string (or something) to put them back down should this happen again.
If successful, I'll document it up.

By the way, when you say "...connector is easily prised off from..." Does "prised" mean pried? As in to pry off?
 

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An emergency pull WIRE would be possible. It will need a strong wire as the force is considerable. Pull in the direction of the red arrow, ie DOWN.
W220 Rear Head Rest Actuator Lever.JPG

I have just purchased a new actuator as my RL one has a split in the diaphragm.
W220 Rear Head Rest Failed Diaphragm.JPG

Brian
BTW I understand your joke;
Pried is the verb form of pry, to enquire too inquisitively into a person's private affair.
Prised is the verb form of prise, to use force in order to move, move apart, or open (something).
 

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Discussion Starter #19
An emergency pull WIRE would be possible. It will need a strong wire as the force is considerable. Pull in the direction of the red arrow, ie DOWN.
View attachment 2448679

BTW I understand your joke;
Pried is the verb form of pry, to enquire too inquisitively into a person's private affair.
Prised is the verb form of prise, to use force in order to move, move apart, or open (something).
Although having lived within multiple states\cities on two continents and having a mother who was an English teacher, I'd never encountered the verb 'prised' in this context (to force open). However, it's entirely possible my younger Navy/drinking days killed those brain cells, and I've simply forgotten.
So I've learned something new (or again). Given the Cambridge definition: As verbs ... pry is to ... use leverage to open ... while prise is to force with a lever; And given the gentleness one must maintain while disassembling the delicate and brittle clips throughout these vehicles, I believe the verb pry would be most appropriate. And...I imagine the entire conversation would be lost on the vast majority. ;-)
.....
I've begun disassembly (finally) and continue to be appreciative of your time and efforts in documenting the steps required.
I'll take photos and keep you guys in the loop.
Note the two dimes (20垄) found under seat cushions. Far less money than what I typically find when dissasembling an interior! :(
 

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Looks like you're doing pretty well so far.

That center seat is a clip-in. There are two in front, two in rear. The rear ones seem to be the tightest (yes, yes, I know :D).

For the middle seat back (i. e. armrest), there are nuts on the bottom and bolts on the top. The bolts on the top also hold the left and right seat backs. Each seat back has another bolt on its other side holding it in.

From there, the seats should come out pretty easily. You might as well take that brown insulation out and look behind it, too, just to see how things are back there, since you have everything apart already. I found a little more money. :) I also found some gunk, which I cleaned up.
 
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