making W123 front seat firmer
 

I wasn't happy with how soft the bottom seat springs are, so I went to my local farm supply store and purchased an inner tube (4" inside diameter). After applying duct tape to the sharp metal edges under the seat, I place the uninflated inner tube between the seat bottom and the metal plate. Then I inflated the tube to my liking. Much better!

John:laugh2:

..and there is actually an OEM part to firm up your seats - MB calls them seat booster pads.
http://w124.f0e.net/ebay4/seatboost1.jpg

That is awesome! Was it hard to install? It's like custom pnuematic lumbar support!

Wow, I never knew those existed. Any chance you have the P/N?

inner tube
 

Not hard at all. Skinned my knuckles a little applying the duct tape which will hopefully prevent the sharp edges from slicing into the inner tube. I attached my bicycle air pump to the tube before placing the tube under the seat. $4.00 well spent!

John

booster pads
 

These look like solid rubber tubes. On another thread someone had mentioned using styrofoam pool noodles as bolsters. Probably cheaper than these.

John

Someone made the point, though, that the pool noodles are 'open cell' foam, which will degrade quickly and make a mess under the seat to boot. I would expect the MB part is closed cell foam. But the inner tube sounds like pure genius!

they sure look like open cell foam to me.
I can get 4 foot sections of closed foam insulation, called armorflex from my HVAC supplier, I would think 1" nominal 3/4id would work well.
John

Look no further than the top of the page!
http://http://www.peachparts.com/shopforum/showthread.php?t=183654

Are those Mercedes things supposed to go at each front corner of the seat? Because the replacement drivers seat I recently installed had coil springs at the front corners that were not on the original.

- Peter.

Here is the diagram
A Forum Member is selling these on Ebay - and I have bought from him super guy.
http://cgi.ebay.com/ebaymotors/MERCEDES-W123-300D-123-W126-300SD-126-Seat-Booster-Pads_W0QQcmdZViewItemQQcategoryZ33701QQitemZ150106394367QQrdZ1QQsspagenameZWDVW

Saves on the hemrrhoids/piles too

Ah. I see. My original seats had no coil springs in them at all. I guess the upgrade wasn't sufficient of an upgrade after all so they had to use pool noodles.

- Peter.

That is an act of genius! :) :D :)

What I did (certainly not as clever) was cut some 4" - 6" x ~12" strips of heavy corrigated cardboard and slid them between the seat bottom padding and the lateral springs. I added just enought to 'lift' the badly depressed area of the seat and it actually feels much better. :D