Done! I've wanted new 124 seats as mine have 293k miles of butt-compression. I've longed for modern seats to replace the originals with old-school soft spring action. And it turns out one of my seat springs was broken.

2 weeks ago I found a nice pair of modern seats on an E320 at a local junk yard - good lumbar lower back support and firm seat bolsters, got the VIN and asked this forum and MB dealer about compatibility...not...responses cited wiring diagrams showing that the electronics/wiring are different.

But back at the junkyard I decided to sit and look again, the passenger seat was easily accessible and I looked under the seat to see it looked like my 87's electrics/mech. So I negotiated the deal and swapped the passenger seat. It plugged right in, the chassis wiring and electronics matched. plug and play! Unfortunately that is where the easy fun ended.

I pulled the driver seat and stuffed it into the back with my old pass seat and drove home.

Chilo at the junk yard said the seats were not compatible because the new 124 seats have a "brain" - meaning 2 position memory. I said mine has memory, too. But it turns out the main long wiring harness plugs did not align. A 124 expert at the local MB dealership said that given the choice between dismantling the seats and swapping seat chassis, he'd get the wiring harness ($190 new) at the junk yard cheap. I went back to the yard and got it - as much fun as pulling veins from a dead rhino! I seriously doubted my ability to stuff it into my car - and into the door to the new seat controller. (Note: for sale - driver's side seat harness, cheap.) I also got the driver's seatbelt - great move as mine was no longer a competent recoiler, and the back of the belt clip had broken, so the clip fell to the floor...also Note: it needed some old seat-pillar parts swapped in, but it works great.)

Anyway, I went back to the basics and followed earlier advice from Sixto and Dave (Gsxr of 124 SportLine seat fame) to consider remounting the seats on my old seat chassis. First I butchered the old passenger seat to see how it went together. Note: before removing your seat, raise seat all the way, and run it forward (exposing the brass colored philips or torx screw on the front of each side. This screw is at the front of each side and screws up from the chassis into the bottom of the black tubular seat-bottom.) The seat-chassis and the seat-back are bolted to the seat-bottom by just 4 (13mm) brass bolts and 2 phillips or torx screws. But since I didn't run the old passenger seat fwd, the screw was not accessible (Milwaukee Sawsall with "The Torch" hacksaw blades took out the screw top, then "pop" the chassis off with a hammer and a screwdriver/chisel.), then clip some zip ties and stare at the fallen parts. Traced wires, drew a wiring diagram, I also "opened" the seat-back and the seat-bottom to see what is inside, how it is built, how it can be amended (to "open" the leather, use a screwdriver to pry out the leather/metal edge - every 2 inches - and then push down and hold (compress) the seat and pull out the leather edge (needlenose/screwdriver/fingers). Easier said than done - my hands feel worked!) Then I got up my courage and did the same to the "new" E320 driver seat. Sawsall, grinder and dremel, clip zips, traced wires, drew diagram. That is when I noticed that the seat-back of the E320's main plugs were identical (same big wire-plugs and small wire-plugs in the same plug array) to 2 on my old 300 - but the wires' colors were different. There were also smaller wire-plugs for the telephone and for the headrest.) I'll try uploading a photo to show where these 2 main seat-back plugs go (middle of the E320 chassis wiring area, the #1 and #2 of 5 internal plugs.)

So going "all in", I unplugged (from the front) my old driver's seat (remember adjust seat fwd and up), and unbolted (10mm ratchet, from the back go inside through the chassis frame), then unscrewed the 6 screws/bolts, and clipped the zip ties. Then I plugged in the big E320's 2 large seat's seat-back plugs into the old 300 driver's seat chassis, rebolted (2 screws and 4 bolts) the new seat-bottom and new seat-back to the old chassis. Stuffed it into the car, and plugged in the car's 3 big front wiring plugs. Hit the door controls and... "It's alive!" Bolted them down (be sure to attach the plastic side skirts first, careful not to break their brittle bits). All with no wire splicing!

Headrests didn't previously work, still don't. but everything else does, and I'm really liking the new comfort ride! While I had the seat-bottom off, I stuffed a firm wad of closed cell foam under the front (to bolster my thighs) giving my long legs great support on long rides.

I also got the new driver's armrest (removed phone to make storage space) and I got the center console wood (needs hole cut out for front/back stereo controller), and the wood-slat-topped closing box. My wife insists all these are projects for later...
Later...

Hmmmm my 93 set of seats may fit in the 87 I'm contemplating... interesting...

If only I could find a late 124 wagon with gray leather, ... could use the update.

__________________

Gone to the dark side

- Jeff

Here is the photo of the 87 seat chassis. The 2 plugs in hand show the location/configuration of the 2 plugs swaped when replacing/rewiring the seat-back from a newer e320 seat to my driver's side '87 300TD seat chassis. The 2 plugs from the e320 seat-back wiring harness just plug directly into the receivers shown next to the pulled plugs. And the seatbelt plug is also the same. Before removing any seat, remember to adjust the seat up and back to get the best access to the floor bolts, and for accessing the 2 screws at the front of the chassis. Also note that the e320 passenger seat chassis plugged directly into the "87 wiring harness - no dismantling required. Good luck.

Attached Thumbnails

 

Thanks for the tip.

__________________

Gone to the dark side

- Jeff

Thanks again John, doing this tonight.

__________________

Gone to the dark side

- Jeff

John.

I'm interested in doing something similar with my 1990 w124 (300D). My car does not have memory but does have electric seats. Can you tell me what else I would need to get besides the seat and the wiring harness if I'm going to install a memory-seat into my car? Thanks.

Stuart

... I'm fairly certain the memory controller is in the seat, so if you pulled the seats, the wiring all the way to the door switches, and the door switches that should do it.

__________________
John HAUL AWAY, OR CRUSHED CARS!!! HELP ME keep the cars out of the crusher! A/C Thread
"as I ride with my a/c on... I have fond memories of sweaty oily saturdays and spewing R12 into the air. THANKS for all you do!

My drivers:
1987 190D 2.5Turbo
1987 560SL convertible
1987 190D 2.5-5SPEED!!!

1987 300TD
2005 Dodge Sprinter 2500 158"WB
1994GMC 2500 6.5Turbo truck... I had to put the ladder somewhere!

Thanks.

I'm only 6' 1" but my legs are unusually short and my torso long. In my car I have to push the set settings all the way to their limit to be comfortable while I drive. To leave the car I must both move back and tilt down to easily get in and out.

It would be great if I could set memory for my getting in/out & a second setting for driving.

Will w126 seats fit in a '90 w124?

I don't believe that the 126 seats will fit, too wide.

I agree with John on the swap: door switch, wiring harness, memory seat base. Your original seat can be mounted on the seat base but I believe that the seat back from the memory seat will have to be mounte on the base also (in case you find a nice seat that doesn't match).

There are two versions of the memory seat, an early and a late, be sure that you get the switch/wiring/seat from the same version.

__________________

Gone to the dark side

- Jeff

Jeff,

It sounds like you are saying that I can just take the base/wiring harness/switch and leave the seat behind. Am I understanding you correctly?

If so will it be apparent, once I turn the seat over, how to separate the base from the seat?

Thanks.

Stuart