Three years ago I found a spotless like new front seat for my 85 300D.
The passenger seat on the other hand is in SAD shape, sitting in it feels like sitting in a chair a 450 pound man sat in for 20 years--its just dead slack.
What's the easiest way to fix this--I have fiddled with seats and doing upholstery is not that much a black art to me, but just the same, I dont want to hand make a chair.
Besides plying junkyards for a replacement, whats the "REPAIR" solution...

I recently repaired the driver's seat on the SDL. It's a bit more difficult than the 123 because of all the seat motors, however, the concept is the same.

You need to get the seat out of the vehicle and then take it apart. It is likely that the seat pad needs to be replaced. However, on the SDL, the seat spring frame had three broken springs, so this also needed to be replaced. The pad is about $100. The seat spring is a bit over $200.

I'm assuming that the 123 is fundamentally the same as the 126 - if not then the rest of this will not interest you!

The seat base is made up of a series of wire rods bent into springs, and in some places the springs are welded to each other. What will have happened is that several of these rods have broken, allowing the seat base to collapse.

If you have time on your hands, and are adept at welding, you could presumably take the seat apart and attempt to repair the spings by welding them back together again. The rubber/hair pad that rests on top of the springs, and over which the upholstery cover is stretched, will likely be past it's sell by date too, so it will need seeing to.

In the case of my drivers seat I decided there was no true repair, only a partial replace. I removed the seat from the car, dismantled the seat back from the base, removed the leather covers and separated the spring base from the motor assembly and rails.

I ordered a replacement (genuine MB) seat base spring and rubber/hair mat from performance products and put everything back together using the new parts.

I still have the old seat base and pad, and could probably find time to take pictures if anyone is interested in seeing what they look like. The new spring base has reinforcements in it that were not present in the original, perhaps it will last longer?

There are posts out there already that detail the whole procedure, and include pictures from memory.

Kevin

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'85 300SD

Yup. It's the same for the 123. Your springs are likely broken and the pad is tired. Some have had temporary success with stuffing a couple of tennis balls in the springs to prop things up but if you're keeping the car for a while replacing the springs with the newer, stronger version (it's all they sell now) is worth it. If you're replacing the springs it makes sense to replace the pad too, it makes a difference. By the way, the passenger seats in the junk yards are usually the ones in decent shape so that fix ought to be on your radar screen.

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LRG
1987 300D Turbo 175K
2006 Toyota Prius, efficent but no soul
1985 300 TDT(130K miles of trouble free motoring)now sold

Best $$ I've spent on my cars was replacing the drivers seat springs - on the ones that needed it anyway. I would recommend only going with a new MB spring too.

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Jim

I second that suggestion also from experience. I also noted that the p/n for the new style replacement seats (for the W123 ) starts with 126 XXX. I had the paper tag that came with one somewhere if your interested I may be able to find it. The springs are significantly different between the old and the new.

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'95 E320 Wagon my favorite road car. '99 E300D wolf in sheeps body, '87 300D Sportline suspension, '79 300TD w/ 617.952 engine at 367,750 and counting!

Carrameow

With the two sets of rails things can get confusing when your doing a swap. First make sure both adjustments (sets of rails) are working as easy as possible because they must be moved around allot to access mounting bolts. Have an philips impect driver handy, I have found it to be a very usefull tool.

I agree with the others, money well spend, makes you feel like your driving a "new car"

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1985 Euro 240D 5 spd 140K
1979 240D 5 spd, 40K on engine rebuild
1994 Dodge/Cummins, 5 spd, 121K
1964 Allice Chalmers D15 tractor
2014 Kubota L3800 tractor
1964 VW bug

"Lifes too short to drive a boring car"

It's on my list, and I ordered a complete book from **************.com it is definitley a good book complete with pics and step by step instructions.


Joe
300CDT 125k

PADDING PADDING PADDING, When I had my drivers seat redone with a new frame a few weeks ago I had a nice layer of high density foam added between the pad and leather. Made a world of difference it honestly feels like modern car to me now. whunter can vouch for the comfort of my seat as well

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Adam Lumsden
(83) 300D
Vice-President of the MBCA International Stars Section

I was afraid you would all laugh and say I am nutty for wanting to do this...

If you will do a search there are some great threads about this stuff...
Including parts numbers for things like " Orthopedic Springs" for big boys...
I think Jbaj007 posted those...

.............from a guy who is crawling under a Volvo tearing off the exhaust system in the middle of New York City at 2:00 in the morning???

nope, not nutty at all.

I had several broken springs in my 116, very similar if not identical to the 123 seats. I welded the broken springs back together, used the "pool noodle" trick to give some more support, and added a 1/2" thick piece of "ethafoam" just under the cover. Only took a couple of hours start to finish, the seat feels great, and I didn't spend a dime.

SteveM.

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'93 190E/D 2.5 Turbodiesel 5-speed (daily driver)
'87 190D 2.5 Turbo rustbucket - parts car
'84 Dodge Rampage diesel - Land Speed Record Holder
'13 Ram 2500 Diesel
'05 Toyota 4Runner

" Pool Noodles " , " Did not spend a dime".....
So in the spring your 6 year old daughter will be wondering where her ' noodles' went ?
LOL