300SD seat swap - and resulting damage.

[tenknots]

Today, I swapped the two front seats- the driver's was really bad due to broken and weak springs. Took me about 3.5 hours, having never done anything like that before. I'll write more later if anyone is interested in how to do it.

But, when I was putting the driver's seat back in, it got jammed on the turn signal stalk and before I knew what happened, it broke! Now I need another combination switch (MB's term) and new ones are nearly $200. Does anyone have one they would sell me? The 300D is a different part number than the SD, so it has to be for an SD - probably 81-85 are the same. This is my daily driver and I need it quick!

Thanks!

Hans 1981 300SD

[Brian Carlton]

If you cannot find a decent used one:

https://www.***************/catalog/lookup_parts.cfm?SubcategoryID=4832&VehicleID=1194005&CFID=509229&CFToken=13390284

Saves a few bucks, anyway.

Had to buy one myself due to a failure of the washer switch.

[Larry Delor]

Let me know how much they want, and I can see what they want at my local yard. (they have an SD and a SEL there right now)

[Eric Eliel]

The Pick UR Part places are pretty cheap for this type of item. Just takes time.

The ideal situation is to find someone that pulled the steering wheel and just left it all apart
Then you go in, remove the few screws and wires, and you are good to go!
I have a turn signal assembly sitting in the garage with a non-working turn cancel. I haven't tried to fix it yet even though I know whats wrong.
If you REALLY need one I can send this not perfect one.

Brandon

[Brian Carlton]

It's not going to be all that much fun getting the switch out. The wheel needs to come off and the cluster needs to come out to gain access to the big connector plug. I've been checking it out over the last week and planning the R & R.

Boy, I remember when R&R meant rest and relaxation.

Originally Posted by Brian Carlton

It's not going to be all that much fun getting the switch out. The wheel needs to come off and the cluster needs to come out to gain access to the big connector plug.

I thought the connectors were acessable from the kick panels below? (if removed)

This is on the 81 though so I may be mistaken.

When I changed my switch, the one I got from the yard had the wrong connectors/wire lengths on it so I swapped my harness over
Go go soldering iron!

[Brian Carlton]

Could be on the '81.

The '86 had the connector directly behind and below the speedometer. It's a PITA to reach and, almost impossible to disengage the pins. In fact, I had to reach up from below to assist in prying the connector from the sockets. My fingers were not strong enough to simply pull it out from the awkward position of my wrist.

[JimmyL]

Did you take pictures of the seat swap? We luvs us some pictures of all repair work! I have a photo archive I love to add to.
JL

[tenknots]

Thanks for the offers of help. If I don't see anyone here with a working switch for sale by this afternoon, I'll order one from Potomac in Florida - they say they have one on their website. Thanks Larry, for the offer to get one at the junkyard for me - very nice of you, but yesterday I super-glued the stalk and so far it's holding. I'll order one for when it does break (soon, I'm sure).

My camera batteries died as I was starting the swap so all I have are pix of the seats out of the car and a rather clever way I found to repair the springs. I'll try to post them when I download them later along with a description if anyone is interested.

[tenknots]

Well, I ordered a used switch from Potomac auto parts in FL for $40. Next week I'll see how much fun it is to replace.

As for the seats, it's not a hard job to do, just a little timeconsuming. In a nutshell:

Power seat all the way forward. There are 2 10mm bolts that fasten the black metal frame to the car - Mercedes has thoughtfully angled the bolts so that a socket wrench with extension will get to them easily. Initially I tried to unbolt the silver track from the black frame, but it won't work that way - you have to remove the whole assy (seat and black frame/motors) because to get the seats off the frame, you can only get to the screws from underneath.

OK, now power the seat back and remove the 10mm bolts from the front. The seat is now loose. But you also need to remove the seat belt track guide from the trans hump (actually in the back seat area - you'll see it). It's a 10mm also. Pop off the cover with your fingers or a screwdriver. Don't let the large washer fall between the hump and carpet. There's also a small rubber washer Mercedes installed to keep out road noise.

Now you need to disconnect a sizeable connector from the front. I used a pair of channel-locks to gently pry it off - it's hard to get your hand in there.

The seat can now be removed through the front door. The passenger's seat is easier since there is no arm rests. It's a tight fit through the driver's door. Watch the seat belt guide - it tends to hang up going through the door. I removed both seats by myself. Buy yourself something nice with the change you'll find. And don't forget to vacuum - it will be your only chance.

One of the motors on the pass seat wasn't working, and I wanted to keep the frame/motor assy in their original place so I needed to remove the frame/motor assy from each seat. There are 6 largish screws accessable from underneath. Put the seats on the ground and tip them up to get to them. You have to move the seats on their tracks to get to them and there are a couple of ways. You can attach a 12v source to the correct pins on the connector and power the seat or do it manually. The motors are easily accessable while the seats are on the ground and there is a square opening on each motor that drives the cables. The cables are actually on the other side of the motor, but there are fittings on both sides. The trick is finding something that fits in the square opening and using a drill to spin it. I found a square drive bit that came with a set of drivers I have that loosely fit it. I stuck that fitting in a metric driver to give me an extension, chucked it into the drill and - zip - the seat moved great. The screws are in pretty tight, but a star bit got them out easily. 2 screws are accessed though a hole in the track - it's easy to see.

Now the seat is loose from the frame, but you'll want to remove the seatbelt warning wires before separating the two. I used the "I Hate Seatbelt Warning Lights and Buzzers Anyway" method and just cut them. On the driver's seat only, there is a small connector next to the large connector that I think tells the stupid buzzer/light that yes, you really did buckle up. You can disconnect it and undo the clips and fish it out or follow the method I used and snip the wires. It makes a big difference to me not having to listen the the buzzer while I pre-heat the GPs.

Also, before you get the seat off, the seatbelt buckles should come off because you need to change sides. Pry off the plastic cover (gently) and you'll see a clip that comes off. Once that's done, remove the seatbelt and rod by sliding it out of the guide - it's obvious.

Now, just swap seats/frames. The seatbelt buckle/guide rod that you just took off goes on the opposite side of the seat now. But you have to remove the stud it attaches to first and change it with the bolt on the opposite side of the seat - you'll see it.

Screw the seat frame back on and you're done, right? Nope. Now you have to change the armrest. This could be a *****, or not. Remove the back cover of both seats (two screws at the bottom of the back cover, then pull it down and off). On the driver's seat there is a harky nut that holds on the arm rest. I don't know the size, but it is bigger than a 1" socket, which is the biggest I have. Not wanting to drive the car to the hardware store without seats, I improvised. The nut is locked on with a toothed washer under it and it's pretty tight. A socket is the only wrench that would fit it. (Note: those with squeamish stomachs might want to read no further) Out came the big cold chisel and hammer and after several blows on the edge in the direction of loosening, it finally moved. Then I put a crescent wrench on it perpendicular to how it should go (sorry Dad, I said I'd never abuse my tools this way) and used another wrench to turn it. It didn't look pretty, but it came off. The arm rest will now come off. There is also a stout bracket that needs to come off from the same area (one bolt) and be fitted onto the other seat - you'll see it. You have to cut a screw sized hole in the upholstery to get the bolt out (if you don't like doing that, wait till you cut the hole for the armrest!). My seats are leather and a pocket knife worked fine.

Transfer the bracket to the other seat (you'll need the same hole punched). Now cut a hole in the upholstery where the arm rest goes - you'll be able to feel it though the leather. It's really only about a half inch in diameter and will be hidden by the arm rest - alas, the other seat will bear the scar forever.

Installation of the rest is the reverse. I seem to remember having to remove a couple of medium sized plastic trim pieces to get to the seatbelts and those have to be swapped right to left, or vice versa. You'll see.

Now you're ready to put the seats in. Warning: when putting the driver's seat in, due to the space taken up by the armrest, the seat may get stuck on the turnsignal stalk. Trying to force it past said stalk (though you probably don't know what you're hung on) will break it. I know.

The rest is easy. Bolt seats in place, bolt seatbelt guide, reconnect cable, marvel at new seat comfort.

Actually, I'm still getting used to mine. I was sitting sideways for so long that my butt grew that way I think. The new seat is great, but either the OTHER side is sagging a tiny bit, or I have to give my body time to adjust. Regardless, the passenger seat is in infinitely better shape than the driver's seat was. It's firm and all the springs are where they should be. A worthwhile project.

Took me about 3.5 hours of mostly busy work. Not a lot of thinking or cussing. Not hard to do.

I apologize in advance if I forgot something.

[James L]

Here is what I did to prevent what happened, remove bottom rear seat, enter drivers seat through rear door, put towel next to paint so not to scratch. Passenger seat can go through front door or rear door. Remove/install black seat belt slider along with seat (10mm bolt on sides of backseat driveshaft tunnel).

[abe g]

If you want to tighten up the springs on your seats, use C clips (hog rings). to the frame and spring to spring (also any broken springs) this will give you pretty good firmness. In fact you can tighten springs to firmer than original ( For you real heavy guys) good luck, Abe G

[waybomb]

Abe G
Can you explain the c-clip thing? What kind and how are they attached?
Thanks

[abe g]

Any auto supply store has a set of inexpensive (JCWhitney mail order) clips and pliers that force the rings closed around springs, to attatch etc. elementery procedure just "clip" parts together. Good luck,, Abe G