Just replaced the seat springs in my 83 300 sd. As usual, the left side (door) springs were broken. Found a seat in junkyard. Stripped upholstery and horsehair pad. Lots of new springs-most broken on left side. Drat.
Decided to innovate. Using hammer and cold chisel, opened the slots where springs slide into seat pan. Removed good springs.
Using grinder-lopped them in half.
Open slots on 'my' seat. Removed broken spring halves. Resprung seat with 'new' half springs-reversed from old seat. Closed slots with hammer and chisel.
Used steel wire to wrap/reinforce all joints and tied most of the
springs together to distribute load more evenly. Reinstalled foam
pad. Seat feels great. Will reinstall upholstery in am.

jonesy,

could you post the procedure for taking the seat apart? i managed to get the seat out of the car. i would like to remove the uphostery and everything. thanks.

__________________
Jennifer
90 350sdl

Considering the forum you've chosen to post in . . . is it the seat on the right . . . or the left?

Sure. Here's something from another website. I have a 300 sd and it worked exactly like this. My seats are electric and weigh a ton. Also had to remove a very balky multi pin connector and seat belt cable. Since I was replacing springs, I had to take the seat back off. Four bolts. Set back aside. Flip seat over on clean surface.
Seat covers are held in place by friction fit. Material is wrapped around pieces of cardboard and pressed into front, side, and rear channels. You have to press down on the seat to detension the material to remove from the channel. I used a thin prybar-a beehive tool-to wiggle in the channel to loosen the material. Loosen the rear channel first. Then do sides and front. When you start removing the cover-you'll have to snip through several cotton ties holding material to backing.
Remove cover.
Clip thru 12-20 wire hog rings holding backing to springs. Make sure to get all the little pieces, or they'll be in your fanny.

Got an electric seat switch you don't need?


Replacing Seat Springs
on a 1977-1985 123 Chassis (280E, 300D, etc.)
with possible application to other models

Introduction

The technical material for this FAQ (Frequently Asked Question) was provided by Stan Protigal of San Jose, California (thanks, Stan!), was edited by Richard Easley of Baylor University, and is provided as a service to the subscribers of the Mercedes-Benz Discussion List.

The project is for a "light do it yourselfer" BUT you must be patient in lining up bolt holes in the spring-loaded parts. It involves about 1 hour's work, but will normally take several hours to complete. Add another 45 minutes if you re-drill the mounting holes for extra legroom.



Mercedes-Benz dealers sell the seat frame, the upholstery and the horsehair-and-foam cushion as separate items. These may also be available through the aftermarket, though I’m not sure. With the seat cover off, it may be possible to add strips of foam under the outside edges of the seat. Doing so normally would add side support. I have not tried this and am not sure how it would work with Mercedes' seat spring arrangement. It may be problematic in that it might stretch the seat covers and damage them.



Adding Legroom



I am 6-3 (190 cm) and had previously re-positioned the donor seat frame, which is now in the driver's position. I am very pleased with the results. With the repositioning and the removed aft limit washer, I gained 2-3 inches without using "drilled strips".



It is possible to drill a set of holes forward of the nutplates on the seat frame. If you do this, use separate lockwashers under the nuts and not self-locking nuts. The lockwasher goes adjacent the nut

and not under the screw head. Flat washers can go between the lockwasher and the drilled material but this is not necessary in this particular case.

To receive similar quality tips as described below on a daily basis, consider subscribing to the Mercedes-Benz Discussion List, which is located at the following site:

http://hsb.baylor.edu/html/easley/mercedes/welcome.html


Assumptions

Using the categories of mechanical ability from the Mercedes-Benz Discussion List <http://hsb.baylor.edu/html/easley/mercedes/subscribe.html>, you need to be at the level of "Medium Do-It-Yourselfer" at minimum, to replace the seat springs. If you are below that level, you may want to provide these instructions for someone who is at the medium level or beyond.



Potential uses of this FAQ:



1. Seat cushion frame replacement.

2. Swapping left/right seat bottoms.

3. Multiple seat rails with spring releases changing to adjustable rails (probably 240D and Euro have the ones that are only fore-aft adjustable on the right side).

4. Upholstery swapping.

5. Removing headrest.

6. Wasting an otherwise good afternoon!





Tools needed:



¼” drive 8mm, 13mm sockets, with extensions.
Magnetic Philips screwdriver (#3 Philips preferred, but #2 works).
Wrench (to assist turning the screwdriver).
Vice grips (small vice grips optional).
Large flat-bladed screwdriver (to carefully remove the plastic trim).
Dry lube for the seat tracks (silicone or LPT-1, or Tri-Flon).


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 (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

Note: To receive similar quality tips as described above on a daily basis, consider subscribing to the Mercedes-Benz Discussion List, which is located at the following site:

http://hsb.baylor.edu/html/easley/mercedes/welcome.html

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

The Mercedes-Benz Discussion List is not affiliated with any other Mercedes-Benz electronic discussion lists nor is it affiliated with Mercedes-Benz of North America or any of its subsidiaries.

So sorry. Still getting used to the site.
Driver's seat.

Reinstalled seat this afternoon. Drove the car again. Boy, what a difference. Before seat repair, was using a sofa cushion to support left side fanny.

Now, seat is nice and even. Tying springs together added much more support. Even got the old seat cushion on without trashing it.