Hi gang, I bought a nice one-year-only M112 E37 powered SWB S350 (2006). It has low miles but has been maintained indifferently for the past 19 years --- I am recommissioning it so that I can use it for daily driving use.
I've always wanted a 6 cylinder Sonderklasse -- specifically I have admired the w126 300SE --- but I don't want to daily drive a w126 on roadtrips so a w220 it is!
Pictures from the advertisement -- I picked up the car in the midwest and drove it home to the west coast this summer.

 

Replacing the front brake pads with Akebono pads (less dust) and changing the brake fluid. I also adjusted the front wheel bearings. The existing discs look to be in good shape -- no need to replace them yet since the front discs are just under 28mm in thickness

 

Replaced rear pads w Akebonos. Don’t be dumb like me and use your fancy Motiv power bleeder to bleed the calipers when the calipers are dismounted … else you will pop the pistons out. 🤦‍♂️

 

Caught a mouse in the battery area in the trunk! I went to look at the battery and I saw two eyes looking at me! New AGM battery installed --- the first Costco / Interstate AGM wouldn't hold a charge (made in Germany) so I replaced that with a 2nd Costco / Interstate AGM (made in Korea) that works.

 

The car had a hot idle stumble ----- during the 2000 mile trip, driving steady state on the freeway was fine. However, driving on city streets, when slowing to a stop at a traffic light, the engine would stumble and sometimes stall. I replaced the MAF with a new Bosch unit, reseated a MAF gasket that appeared to be wonky and also replaced the crankshaft position sensor. FWIW, the CKP on this car is SO EASY TO CHANGE (because there's so much room in the engine bay with a v6)

I used a Bosch MAF (made in DE) to replace the old Mercedes branded Bosch MAF (also made in DE)



The CKP was even easier to change on this car compared to my w210 with the m112 e32 v6 ... because there is more clearance between the engine and the firewall. I just needed one extension on my ratchet to get to the CKP -- no need for any u-joints on the ratchet and no need for multiple extensions.

 

My instrument cluster experienced failure symptoms - the middle LCD losing contrast and the lighting on the speedo was inconsistent - the right side of the speedo was more dim than the left side. This, of course, was covered under an extended warranty by MB ---- all the way to Jan 2016 according to the VMI I had pulled for the car. Unfortunately, now, in 2025, we are almost a decade beyond 2016! 😭

I pulled out the instrument cluster with cheap radio keys that only worked for the left side. The right side was stuck and my cheap radio key would pull out of the slot before budging the instrument cluster. I finally had to remove the center HVAC air nozzle to remove the right side of the instrument cluster.
Then I figured out --- using nicer radio keys with a deeper notch works MUCH MUCH better. The deeper notch enable the keys to engage the cluster securely and will pull out the cluster without issue!
I should give a plug to Peter at Odo-Pro ---> Mercedes . I sent my cluster to Peter at Odo-Pro and he replaced a transformer, some transistors, and the center LCD and sent the cluster back to me all for a super reasonble price ---- HIGHLY recommended!

 

I changed out the fuel filter ----- I can never be bothered to empty the fuel tank before doing this so I always just use two pinch-hose clamps and lose to pinch off the fuel lines before replacing the fuel filter.
The ClicR tool that I have is AWESOME --- it totally make short work of all these "Hoff" German OE hose clamps.
The old filter was original to the car and waaaaay due for replacement.

 

I pulled up the driver's door lock pin and much to my chagrin, it pulled right out! It looks like someone had totally bruce forced it and sheared the metal rod in two when replacing the door lock actuator at some point. GRRRRR. The previous mechanic had used heat shrink to mend the door lock rod. I repaired it using stronger heat shrink. Getting a new lock rod and refitting it would require disassembly of the door lock actuator... ugh --- I don't wanna touch more stuff. Heat shrinking the two pieces in-situ does not require removal of the actuator. Anyways, this gave me the opportunity to to replace a bunch of plastic clips / missing screws from previous mechanics' attempts at door panel removal. Satisfying.

 

While I had the door panel off, I replaced the external mirror gasket. I'm not sure why my passenger's side gasket looks so nice and supple, whereas my driver's side gasket was super cracked and weather beaten. Anyways, I replaced it with a PRC one --- unfortunately the original MB OE gaskets are NLA. :-( Good enough for now. I will see how long the PRC gasket lasts.

 

When I first picked up the car a little over a month ago, the seat lumbar, rear headrests, and trunk soft close / trunk slide out handle did not work.

That was ok. I could live with that while I worked on more important things (like the engine / trans / etc.). A few times, I had to take out the yellow 25amp fuse under the RR seat a few time to reset the pump when the soft close doors stopped working while I was driving back from the midwest a month ago --- but since then things were ok (with the exception of the lumbar/headrests/trunk stuff that never worked).

Well, today, while putting the car back together from fixing the mirror gasket / window lock, I realized that the power locks totally stopped working and the door soft close totally stopped working too!!! ARRGHHHH. Hope I didn't screw anything up working in the driver's door.

Reset the fuse many times and disconnected the battery for an hour - no dice. Plugged in SDS and got this:



So then I went in the trunk and investigated the PSE pump ---- it doesn't seem to run even when I take out and re-seat the electrical connector. I've never dealt with this before. Someone please tell me that if I get another pump on ebay that all my door soft close, power locks, AND my never-worked before rear headrests / trunk handle / trunk soft close will work!!!! See this video:

You Tube

BTW I note that the existing pump (which someone had replaced before - see the "warranty" sticker) is 220-800-08-48 .... and the EPC calls out (for my VIN) for 07-48, 10-48, 11-48, and 12-48, but not 08-48. 🤷‍♂️



FYI gang --- I looked up the EPC for PSE pump supercessions since there's all kinds of conflicting information out there about "all PSE pumps are the same" or "Mercedes revved the part numbers constantly - just buy one that a higher number than the original pump" or whatever.

According to the EPC, my car came with an 07-48. Someone put in an 08-48. No idea if that person used SDS to code the 08-48 pump to my car or not. Anyways, 08-48 is an EARLIER pump than what my car came with.
See here — It went from 2 -> 5 -> 3 -> 6 -> 8 -> 7 -> 10 -> 11 -> 12.

 

Not likely at all.

 

Need to reprogram it. You can replace electric part and it "should" work. Otherwise in picture can see that STAR is used. Then transfer from old pump to new one coding.

 

I'm not sure why all my previous posts have unreadable text (white text on a white background). Those posts look good in dark mode mode (white text on black background). 🤷‍♂️ If an administrator can fix it, that would be great (I cannot edit my posts). Thanks. 🙏

Anyways, my car has been sinking down to the bumpstops in the front when parked for 48 hours. Specifically, it seemed like the LF corner would sink down the most and drag to LF corner down with it. The rear suspension was fine. This was all very curious as the previous owner had freshly installed Airmatic Arnott rebuilds in the rear, and had freshly installed new Airmatic Arnott units in the front. I suspected the issue was a faulty valve block. Swapping the original valve block with a new aftermarket one seems to have done the trick --- see the pictures detailing the drop in car height after sitting for 24 hours now. I kept the "old" Airmatic pump because it was a Wabco (the OEM supplier to OE MB) pump from 2018. I also replaced the original Airmatic filter and Airmatic relay.

I also took the opportunity to drill out a broken trans bracket bolt and installing a new bolt. Whoever was the previous mechanic for this car was a mouth-breathing gorilla --- I've found several ham-fisted effups that I've had to correct. (And as a small example, why did they replace the pump in 2018, but not replace the valve block or the Airmatic filter / relay?)

 

Very skilled

 

Well, I put in a new (used) PSE pump today. That got my 4-door-soft-close and my 4-door locks working. I had to mend those brittle plastic pneumatic-port-aggregator covers. The are so brittle and were already broken. I also ordered some spares for myself for the future.
I had to go into SDS and re-enable the retractable trunk grip to get my RTG working too. Somehow it was turned off by someone previous --- or the previously installed PSE pump had this coded off.
I deleted any mention of power-trunk-closing via SDS (since my car doesn't have this feature) as well.

RTG works, but trunk soft close doesn't work properly. @wallyp you are right - I have a leak. See video. I'm going to order a new RTG.

 

Update - the air leak affecting my trunk soft close is NOT coming from the RTG retractable trunk grip and is actually coming from the trunk latch. I hacked together a solution with Zip ties and roofing tar but I doubt this will work.

 

damn it seems your care is rare , i read the history of the one year run
i had a w210 v6 and a 09 e350, the v6s were economical, reliable x 1000
keep up the cool work

 

Thanks. Yeah I have a m112 v6 powered w210 as well ….. I happen to have a thing for marginally underpowered but exceptionally smooth Sönderklasse cars. 😅

 

Check your front lower control arm bushings folks! I was fighting the faintest of shimmys through the steering wheel going down the highway at 75 mph. It wasn't out of balance wheels / tires or warped rotors --- it was the front lower control arm bushings. Mine only had 65K miles on it. Replaced them with DE-made Lemfoerders. The steering wheel shakes are gone.

 

I upgraded the wheels to 18x8 Forged MB Segin wheels off an S600. They are nice and light. When I got them, they were in pretty rough shape, so I had them machine finished for an ever-so-slightly less-blingy look than OE (OE is polished finish). The pockets were powdercoated silver, the faces were machined, and then the whole thing was re-powdercoated clear. I love the look.

I also had 245/45/18 Pirelli P-Zero AS Plus 3 Ultra Hi-Perf All Season tires installed. I normally like Continental DWS 06 Plus tires for All Season Hi-Po tires, but decided to try these Pirellis based on Tire Rack reviews that they are quieter and more comfortable than the Conti DWS 06 Plus. So far that has held true.

Anyways, I really like the "OE+" look --- I typically like to stay with MB wheels or +1 sized reproductions of MB wheels on my cars.

 

I drove 400 miles yesterday and I do realize that I celebrated prematurely. I do have steering wheel shakes still. I'm not sure what it is. The vibes are not visible - you cannot see the steering wheel shake. But, you can definitely feel it through the steering wheel, and turning the steering wheel a little bit at 70 mph increases the vibration.

I swapped the spare tire on to the LF and drove the car. Then I swapped the spare tire onto the RF and drove the car some more --- no difference at all. That kinda rules out front tire balance/out-of-roundness, I think.

I took some accelerometer readings with the meter on the instrument cluster - definitely the vibe is related to the tires - 1st order (occurs with 1x relation to the period of one tire rotation). See below.

I wonder if the issue is front control arm balljoint related or tie-rod-end-balljoint related.

 

Find a large, flat, smooth parking lot, and drive across it at a walking pace. See if the car "waddles" - that is, see if one corner gets pushed gently from side-to-side. If so, one or more of your tires may have a tread belt that is not running true.

 

Any updates on your car?

 

In order to "gain more smoothness", I did the following to the front suspension:

• Replaced balljoints in LCA w Lemfoerder (Germany) units
• Replaced outer tie rods (with integral ball joint) with Lemfoerder (Germany) units
• Replaced the front torque struts (arms) (with integral balljoints on one end and new bushings on the other end) with Lemfoerder (Turkey) units. I wasn't able to find German Lemfoerder units here. Interestingly the old units that came out of the car were Lemfoerders as well from 2016 and 2018 --- and the bushings were already cracked!

I had the car aligned - check out the before / after on the toe. Sheesh.

The car feels smoother! Not glass perfect, but pretty nice!

 

I had the two front wheel/tire assemblies roadforced. The car is smoother still! Hunting vibrations is always like this - there is never one silver bullet. Rubber is always deteriorating / imperfect and every little thing that you refresh just incrementally adds up. The fronts are at LF 4lb and RF 17lbs. The rears are at LR 26 lbs and RR 26 lbs.

I didn't want to roadforce the rears because I wasn't super pleased with the shop ---- they roadforced the fronts but they weren't super careful. Red Flag #1 - they questioned why I wanted them to use hand tools only and no impact wrench. Red Flag #2 - they put a scuff in my newly refinished machine-cut wheels and told me its because I needed to wait longer for the finish (powder coat) to cure. Wrong .... Power Coat is cured after baking in the oven, unlike paint.

Luckily I was able to polish out the scuff they put in one of my wheels .... but ..... I feel lucky I got out of that place without damage. If anyone has a recommendation on a SUPER CAREFUL / PICKY shop that roadforces wheels/tires in Orange County, CA, I'm all ears.

I will roadforce the rears when I find the right shop.