My ww2 vet friend wants to put a new drivers side seat in his 1977 240 d.I will do it for him.Will someone send instructions.Thanks Michael.

I have an '81 300TD-T and I just swapped out my driver side for a passenger side. I assume that your 240D is the same...if anyone disagrees please tell me so.
The difficulty lies in if you want to swap out the entire seat or just the cushion.
Entire seat:
If you have another seat, the entire frame is only held to the car with 4 bolts. 2 in front and 2 in back. I had to push my seat all the way to the front, and then adjust it all the way up to get to the rear 2 bolts. Mine had a seatbelt buzzer wire attached so be careful there. Then, the seatbelt clicker (that is the technical term for it ) is attached to a long bar that is attached in the back seat floor area. Just slide it off and pull it out.

If you want to get just the cushion off the frame so that the seat adjusters, etc. all stay with teh car, let me know 'cause that is what I had to do and it is more in-depth than what I can tell you here...

Hope this helps!

__________________
Current: '91 300TE 4MATIC 317k and climbing...
Former:
'81 300TD Wagon 168K "Tank"
'83 240D 216K 4spd manual "Da Bear" (aka best car ever)

"Never sweat the petty things...
and never pet the sweaty things."

I did this job a couple of weeks ago and what a difference it made!

If the back is ok and only the base is collapsed, The base is the same drivers and passengers and according to mecedes parts dept. it has the same part no as the 126.
which means any passengers seat out of a breakers 123 or 126 will tend not to be as worn. Mine came out of a 1981 230
It took me 1/2 hr to take the passenger seat out and about 3 hours to do the rest of the job ( what pillock put a height adjuster on the drivers side) a mate found this on another site and sent it to me and I found it covers most things

Replacing Seat Springs

If the plastic handles are broken (manual seats), they can be replaced. The replacements have bolts.
The seats come off with 8mm bolts or philips screws (same with the seatbelt rail).

Unclip the seatbelt warning cable, if applicable. [On non-adjusting seats a sideways bolt is also there on the outside tower. The manual seats have a rectangular washer to block aft movement. Speculate as to its purpose and toss it.]
Lower seat rails must come off first. [This is to expose the middle screw attaching the upper seat rails to the seats.]
Set seat to forward position (tracks aft), and remove front screws.

Remove seat adjustment assist springs (manual seat).
Use vice grips to hold height adjust handle up, which will enable the height adjust rails to move on their tracks.
Align the rails so the middle screw and aft screws are accessible and remove them.
Remove lower frame rails, which will enable you to get to the middle screw of the upper frame rails.
Remove rear screws attaching top rail to black seat frame.
Align seat rails and remove 2 remaining screws on each rail.
Remove seatback.
Move clips holding seatbelt warning cable by grabbing tab with vicegrips.
Thread cable outside of seat frame.
Clean the dirty oil from 13mm wrench and remove 4 bolts holding the seatback to the bottom seat frame.

If you need to re-use your seat cushion & upholstery, the upholstery is held by its edges. [The edges have cardboard backing and are simply pressed into the seat frame edge.]
To remove the upholstery, spread a large towel on a clean workbench.
Put the seat on it, upholstery side down. This will expose the seat frame.
Press down on the seat. While pressing on the seat, start with a free edge, carefully lifting the edge part of the upholstery from the slots.

Installing the rails is the same, except that the slave side of the vertical adjustment lever. [There is a crossover linkage and the crossover linkage must lift the slave side up.]
Cinch down hard on the screws because the surface is now lubricated with seat track lubricant and that doesn't help secure the screws.
Insert the seatbelt rail before bolting the rear of the seat. [The shaped washer goes behind the plastic trim piece with the raised center facing the rail; the raised edge faces the drive tunnel. A rubber washer holds the bolt in place until secured.]
Finally, let me know if you complete this procedure successfully; it took a while to type this, and I'd appreciate knowing when each person has completed the repair! Please e-mail me at richard_easley@baylor.edu

©1999
Richard Easley, Waco, Texas and Stu Ritter, Denver, Colorado.

Thanks everyone.The seat he got is a compleate one I have not seen it yet .Michael