I just completed the replacement of the lower front drivers side seat spring in the 300SD with the new "updated" style seat spring (there is another thread somewhere in here that provides pics of the old and new style side by side). By far this has got to be one of the harder diy'er jobs that I have completed. Took a solid 5 hours but in my opinion it is one of the jobs that offer the most payback. I would recommend it to anyone. Your back will appreciate it.

In doing this job I ran the battery down. Not exactly sure why but if anyone has an electrical schematic for this car I would appreciate a copy. I suspect that the way to prevent this from happening is to disconnect the battery after seat adjustments are made to access the various screws. I am thinking it is alarm related in the fact that when the drivers seat is disconnected the battery goes dead . I imagine I will eventually get around to disabling the alarm. I really don't want it in operation.

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Jim

...that I did the same job on my 1983 300SD when living in Encino, in the San Fernando Valley in the early 1990s. The spring had broken and the seat bolster leaned to the left when you sat on it, causing hellish pain in the sciatic (I think) nerve. Had some 90k on it at the time, including 45k from the first owner who may have been heavier than me.

I recall it as one of the toughest jobs I ever did as it was 100F at the time, the seat was hell to get out and very heavy and several small plastic trim pieces broke from age when I dismantled it to remove the old spring.

However, it had to be done and the new seat spring showed far stronger gussetting in the middle where the old one had broken. I seem to recall someone writing that all pre-1986 W126s (and earlier W116s?) are plagued with this bad design. Not sure of this but I believe the 1986 and later W126s use the new design. My 1990 W126 is fine at 103k in this regard.

I have over 100k on the replacement in the SD and it's fine. I weigh some 165 lbs, pretty much stable over the years.

Jim:

Sounds almost as much fun as doing the seat covers in the 280 -- in that case, out wasn't too bad, but getting the damn..d seat apart was -- some idiot blue locktited the stinking screws in and I broke two screwdrivers getting them out. Had to heat them in the end. New screws next time, PITA.

Getting the seat back in was worse, I must have heaved that stupid thing in and out six times before I cottoned on the the drill -- get the rear attachements down and installed first (broke one of the fine thread speed nuts by crossthreading it with the nice, soft MB bolt), THEN sit on the seat and force the up/down spring back and lean over and put the front screws in. Natrually, there is only one seat position of all the possibilities that will allow the cushion to move back far enough....

The new seat covers worked out pretty good though if you overlook the electric blue glare. I wonder if this isn't why the leather cover project is sorta stalled out?

Peter

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1972 220D ?? miles
1988 300E 200,012
1987 300D Turbo killed 9/25/07, 275,000 miles
1985 Volvo 740 GLE Turobodiesel 218,000
1972 280 SE 4.5 165, 000 - It runs!