MB Noob: W124 TD Suspension Overhaul
 

Hi everyone I entered the MB world last fall with the purchase of an '87 W124 300TDT, and I've been lurking on the forums since. It has been serving me fantastically so far, but a season of Michigan roads has finally finished off the 160k mile original suspension and it is time for an overhaul.

I've been reading all of the suspension related things and think I have what I need to buy/do mostly figured out, but I still have a few questions. So here is my shopping list so far with some related questions. Please let me know if I've missed anything or gotten anything wrong. Hopefully this list can serve as a good reference for other people down the road.

Front End
-Control Arms (don't want to fiddle with bushings or ball joints so I'm replacing the whole thing)
-Tierods
-Centerlink
-Steering Damper
-Shocks (Not sure which Bilstein I want/need, but I'm looking for comfort over performance and stock ride height, for now)
-Shock boots and bump stops (will these come with the shocks, or do I need to order them separate)
-Strutmounts (One of my friends has a 190 and goes through these like they are going out of style. Which brand is the least likely to fail on me?)

Rear End
-Control Arms (Camber, toe, push, pull, & lower/spring)
-Bushing/compression sleeves (Where do these go? How many are there? Do they need to be replaced?)
-Carrier bushing (Will need a press tool, found a thread outlining how to make one with common parts)
-Hardware upgrade (I read somewhere that they changed the mounting hardware size for some of the suspension. What to I need to get/do to account for this?)
-SLS Struts (They currently work perfectly and don't leak. Is there any potential reason to replace them if they aren't leaking)
-SLS Strut Dust Boot (These are no longer existent on the car, has anyone had any luck replacing them with something aftermarket?)
-SLS Accumulators (Replaced them when I got the wagon, putting it here to show I haven't forgotten them)

The MB SLS struts rarely leak. There's no benefit to replace them if they don't. I have 292K on mine and recently hauled a 1K Lb load 60 miles without a second thought.

The reason for the bushing sleeves and hardware is because MB used the same camber strut on many models and years. The later ones have a larger bolt hole. The sleeve allows the smaller hardware to work without any other mods.

Have you ever replaced the dust boots on your SLS struts, or do you just run them bare?

When I'm shopping how do I know if the camber strut will come with the large or small size holes, or do they all come with the late/large sized holes? What size holes/hardware should mine have? Did they change the size on the inside and outside mountings or just one.

Also, just took a look at the hardware kit for the camber arm and it looks like the bolts are triple square. Is that right? What ratchet attachments/wrenches am I going to need for this job besides the standard metric hex stuff?

I'll mention the steering idler arm bushing kit. Those are often overlooked and almost always toast.

********az sells a complete rear control arm kit for the 124, 129, 201. If you are going this deep into the car, subframe and differential bushings should be done now as well. You don't want to get everything back together and find out you still have a clunk from something that would have taken 30 minutes to do while apart

Stabilizer bar bushings all around too. Basically, if it's a rubber bushing you should replace it no matter what since you will have the car that far apart

Front sway bar bushings (4).

These can cause a rattle when hitting bumps, usually it's the one on the control arm, but I generally replace all four when I'm in there.

Jim

I would do this in phases. First phase, front control arm, shock, shock mount. On the steering parts, I would probably do the tie rod end while there, but would otherwise inspect first and only replace if clearly bad.

After that I would drive awhile and inspect, replacing items only if they are clearly toast. 160K is not a lot of miles for those MB's, and money spent on 28 year old Michigan drivers (vs. garaged classics) should be targeted judiciously.

Front swaybar brackets.

These seem to fatigue on these cars and crack, worth doing while you're there.

Oh yeah, idler arm bushing is a really good one. Surprised I missed that.

That is a good point. I was going to save those for next year. Suspension links seem easy, but subframe always seems like a project. Does having the rear suspension already out make it that much easier?

Swaybar bushings are on my internal list, but less important to me because they should be able to be done later without taking anything else apart, right?

If this was a typical Michigan driver, I was on a tight budget, or it was not my 4th (3rd 80's German) car I would tend to agree with you. However, it is a very clean car from Virginia, the OO/PO garaged it, and I am tired of doing jobs multiple times. If I dive in I'm doing all of it because if one thing is bad the rest is not far behind. This is just my way of handling it at this point.

Thanks, I'll check on them.

I thought it might be nice to give an update on this project. I had half the parts ordered when last week something terrible happened. My wagon got hit by someone turning left when they shouldn't have. The insurance is calling it a total loss. So I am buying it back to sell to one of the local MB guys to fix or part accordingly. In the meantime I am looking for a new vehicle. I would like to either get another W124 wagon with OM603 or M104 or a W126 with M103 or OM603. Please let me know if you have any leads on one of these in good shape.

I also thought it might be nice to post up the updated parts list I made with part numbers.

Front
1243303007 Control Arm L
1243303107 Control Arm R
1243300803 Tie Rod L
1243300903 Tie Rod R
1244600805 Center Link
1244630432 Steering Damper
1244600119 Idler arm bushing
1243203030 Shocks
1243230192 Dust Boots
1243230744 Bump Stops
1243201444 Strut Mounts
1243235085 Bushing: Sway to Control Arm
1243234585 Bushing: Sway to Frame
Rear
2103503406 Camber Arm
2103504506 Camber Arm Hardware Kit
2103502153 Toe Arm
1403501170 Toe Arm Hardware Kit
2103503806 Push Arm
2103504506 Push Arm Hardware Kit
2103503306 Pull Arm
2103504506 Pull Arm Hardware Kit
2203520227 Carrier Bushings
2023520165 Control Arm Bushings
1243200489 Sway Bar Links
1243260581 Swaybar Bushings
N/A SLS Dust Boots
1243511342 Front Diff Bushing
1243527765 Rear Diff Bushings
1243500341 Front Subframe Bushings
1243510242 Rear Subframe Bushings
Other Rubber
1242401917 Motor mounts
1242400618 Trans mount

Sorry to hear about the write off. Still at least it didn't happen after you'd just fitted that nice list of parts...

Very true. I'm also glad the car did it's job and let me walk away