Hi!
W124s seem to get a little hype lately. Though there's something you should check when looking at one, as too many suffer from this damage which stays hidden very long, untill it's too late.
The PVC underseal Mercedes used in the 80s also had to function as a seam sealer. Which doesn't work that well for 20+ years...
I'm taking about the front support for the rear subframe. I've seen subframes which were rusted off, only held by the rear supports...
Doesn't look realy suspicious?
After the wheel of death & truth did it's dirty work:
And this is a MILD case! Some extreme examples:
www.w124-freunde.com/index.php?page=Attachment&attachmentID=1938&h=d8ef10a26b521bf21b58d5f6649e530212ecb636&thumbnail=1
www.vorstheim.de/ebay/100_6471.JPG
data.motor-talk.de/data/galleries/0/119/7113/11759729/sdc10111-33446.JPG !!
data.motor-talk.de/data/galleries/0/119/7113/11759729/sdc10110-15921.JPG
mb124.de/gallery/d/97266-1/Hinterachsaufnahme_1.jpg
It's not evident/seeable unless the wheel is taken off. The rear of this support isn't realy accessible for inspection, but you can get a screwdriver there. And to fix it properly (the rear side), the subframe has to come out! The repair panel is NLA!
Many W124 got scrapped because of rotten subframe supports - once the rot has bitten deep, it's a PITA to fix properly. I was lucky thatonly the outside was rotten. As it was fixable without removing the rear axle.
So if you look at a W124 - take a look at the subframe support
This is common too; but easy to fix. Take off the little lid covering the jacking support. I've hardly seen a W124 without crusty jacking supports... Especially the second & 3rd series ('89 on) where these are hidden under the trim panels rot. As it's not immediately evident, if there'S a problem.
Don't let this stop you - it's easy to fix. The subframe support however... Take a good look & poke it with a stick
(an honest seller will certainly agree with this 
.
[edit] Merged with post from below;
Another very common rust spot I've seen on a lot of W124s; the crossmember below the sump rots away:
Which only becomes evident, once the plastic guard under the engine bay is removed... As it fully covers that area and can rub against it, which probably causes this.
Aaand, of course there are more common rust holes. The front wheel wells rust through where the holder for the front bumper is attached. And there can be a nasty surprise under the washer fluid bottle:
And the corner below the front indicators is usually rusty; rusting through from behind:
For those looking for a wagon; the rear side windows almost always have a big rust issue... Water is trapped in the channel where the window seal resides and causes severe damage. Look carefully for a deformed window seal from the inside and lift the lip in the window corners. If there's rusty bit falling out - remove the windows ASAP. With a bit of luck it's not too late and can be fixed without re-painting as in this case:
But; there are three panels joining each other, one oft them is the lower structure of the C-pillar. Here's an extreme example:
^this is almost impossible to repair properly...
Cheers,
Jan
W124s seem to get a little hype lately. Though there's something you should check when looking at one, as too many suffer from this damage which stays hidden very long, untill it's too late.
The PVC underseal Mercedes used in the 80s also had to function as a seam sealer. Which doesn't work that well for 20+ years...
I'm taking about the front support for the rear subframe. I've seen subframes which were rusted off, only held by the rear supports...
Doesn't look realy suspicious?
After the wheel of death & truth did it's dirty work:
And this is a MILD case! Some extreme examples:
www.w124-freunde.com/index.php?page=Attachment&attachmentID=1938&h=d8ef10a26b521bf21b58d5f6649e530212ecb636&thumbnail=1
www.vorstheim.de/ebay/100_6471.JPG
data.motor-talk.de/data/galleries/0/119/7113/11759729/sdc10111-33446.JPG !!
data.motor-talk.de/data/galleries/0/119/7113/11759729/sdc10110-15921.JPG
mb124.de/gallery/d/97266-1/Hinterachsaufnahme_1.jpg
It's not evident/seeable unless the wheel is taken off. The rear of this support isn't realy accessible for inspection, but you can get a screwdriver there. And to fix it properly (the rear side), the subframe has to come out! The repair panel is NLA!
Many W124 got scrapped because of rotten subframe supports - once the rot has bitten deep, it's a PITA to fix properly. I was lucky thatonly the outside was rotten. As it was fixable without removing the rear axle.
So if you look at a W124 - take a look at the subframe support
This is common too; but easy to fix.
Take off the little lid covering the jacking support. I've hardly seen a W124 without crusty jacking supports... Especially the second & 3rd series ('89 on) where these are hidden under the trim panels rot. As it's not immediately evident, if there'S a problem. Don't let this stop you - it's easy to fix. The subframe support however... Take a good look & poke it with a stick
(an honest seller will certainly agree with this 
.[edit] Merged with post from below;
Another very common rust spot I've seen on a lot of W124s; the crossmember below the sump rots away:
Which only becomes evident, once the plastic guard under the engine bay is removed... As it fully covers that area and can rub against it, which probably causes this.
Aaand, of course there are more common rust holes. The front wheel wells rust through where the holder for the front bumper is attached. And there can be a nasty surprise under the washer fluid bottle:
And the corner below the front indicators is usually rusty; rusting through from behind:
For those looking for a wagon; the rear side windows almost always have a big rust issue... Water is trapped in the channel where the window seal resides and causes severe damage. Look carefully for a deformed window seal from the inside and lift the lip in the window corners. If there's rusty bit falling out - remove the windows ASAP. With a bit of luck it's not too late and can be fixed without re-painting as in this case:
But; there are three panels joining each other, one oft them is the lower structure of the C-pillar. Here's an extreme example:
^this is almost impossible to repair properly...
Cheers,
Jan
2y6BPnUhc8rog~~60_12.JPG)
