Home » I Figured Out Why Old Mercedes Are So Hard To Modify: Project Ski-Klasse

I Figured Out Why Old Mercedes Are So Hard To Modify: Project Ski-Klasse

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This car is a mess. Redundant worthless systems that serve no purpose but throw check engine codes. Basic jobs like swapping a sway bar take 10 hours. Why? Because someone in Stuttgart back in the mid 1990’s must have said “Why not?” Well, if I ever get to talk to them, I know the answer!

[Ed note: We teamed up the legendary Bill Caswell with Vredestein Tires, Hella and FCP Euro to turn an S210 E-Classe into a ski car we call Ski-Klasse (get it?).  – MH]

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Vidframe Min Bottom

Ski Klick

Before we begin, you need to remember that I’m self-taught when it comes to cars. I was a finance guy. Fancy suits, an MBA, and crazy complicated bond deals. So I had to learn cars from books. I did have a local shop owner and racer, Leo Franchi, teach me all the good stuff I couldn’t find in books. Thank you Leo! So when I tell you how much I hate the design of this Mercedes, please remember I don’t really know anything.

Well, that’s not entirely true. I know one thing for sure: If I owned a car company, I would make my engineers — not a team of engineers working together under a lift with one guy doing most of the work — perform all the routine AND long term maintenance on the design before it’s finalized. I would make each one take the entire car apart by themselves with hand tools in a small garage. I guarantee those engineers would design things differently going forward. I’d probably also make them build a race car version before the design is finalized too. Imagine if the E30 and the E30 M3 were conceived hand-in-hand? Anyway, back to our mess.

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Ever build something knowing that you will never ever take it apart? That some poor bastard on other side of the world is going to have to deal with it long after you’re done? I’d still try hard to make it easy. But Mercedes? Nope. They’re like “ohhh… that looks way too simple, can you design it so they have to drop the entire rear subframe and all the suspension just to install something simple like a sway bar?” But they didn’t stop there. Every part of the car got the “Why” treatment.

Those engine mounts can be changed by anyone! What are you thinking Dieter? Bury that top bolt so deep that no ordinary mechanic will ever get it undone! Then we will engineer a special wrench that we can sell them. This way only the chosen ones with our special wrench can take this car apart!” Our car is 24 years old so now we can just order the Baum version through FCP Euro.

Mercedes special wrench

This would normally be enough to piss off any DIY mechanic, but Mercedes took it a step further by locking down all their information. If I need a part for a BMW, I go to www.realoem.com and get an exploded parts diagram of every system with all the part numbers! I can even type in a part and find out what other cars they came on in case I need to source a used part fast. And after all these years, my head now organizes all car parts and systems into the BMW subgroups.

Laptop With Blank Screen Isolated On White Background, White Alu

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Screengrab, realoem.com; laptop, mahod84/stock.adobe.com

Click on a category and you get exploded parts diagrams. Click again and it drills down into the part numbers. When I was new, I also used this to understand how some the parts fit together. Now you could hand me any bolt from an E30 and I’ll tell you where it came from… assuming it’s still the original bolt installed at the factory.

Laptop With Blank Screen Isolated On White Background, White Alu

Screengrab, realoem.com; laptop, mahod84/stock.adobe.com

There is nothing like this for Mercedes, or at least not for guys like me. Mercedes has a proprietary parts software($$$$), which is nightmare when I’m trying to understand all the rubber tubing they ran across their V6 (and the whole chassis). Luckily we have friends that I can text in the middle of the night with stupid questions (Thank you FCP Euro), but it’s still really annoying. Kind of like building a jigsaw puzzle without access to the cover photo. Although, I’m starting with a completed puzzle so its not that bad.

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As a side note, I get why BMW always ran inline six’s. The marketing team and journalists will tell you it’s silky smooth and has a perfect torque curve, but after working on a V6, I’m pretty sure it’s more about the plumbing and wiring. For a rear-wheel drive car with a long nose, a straight six is so much easier to install than a “V” shaped engine. Has to be cheaper too. I understand that some cars only have room for three cylinders before the front bumper, but this Mercedes had so much room I was able to move the radiator back eight to ten inches.

Why build two sets of headers? Two cylinder heads? Two fuel rails? Two pressure regulators? Two sets of vacuum lines for each head and one giant intake manifold that covers everything useful to a mechanic? Plus the entire perimeter of the engine is now surrounded by hot headers compared to inline where one of side of the engine bay is hot and the rest carries fuel, air, and oil [Editor’s Note: And you can share more components/manufacturing processes with inline-fours. -DT] — it makes so much sense to me. Mercedes used to run straight six’s too. Until someone asked… Why?

Redundant Check Engine Lights

Sk Klassse Checklight

How do you think Mercedes measures the air entering an engine? Every car I’ve played with uses a MAF sensor (mass air flow) and I know others use a MAP sensor, which measures the pressure of the air in the manifold. But Mercedes? Why would it ever choose one system over the other when it can run both!

Why? I have no idea. It’s a naturally aspirated V6. Does it run smoother than my BMW with just a MAF? Maybe. But the Mercedes also has softer engine mounts so I doubt that cushiness is the result of the engine runs better. I can’t see how dual metering systems makes the car more reliable, because neither is a back up. If either sensor fails, the car runs poorly. It’s the same reason Lindbergh only used one engine on the Spirit of Saint Louis; why have redundant failure points? I’m surprised Mercedes didn’t include two check engine lights; the company doubled down on everything else.

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I’m picking on the engine, but it’s not like one system is messed up and it’s a funny anomaly. Nope. Every system on the car is bizarre. Except the interior. The interior is perfect. Well…. except for those few buttons on the dash. But the dash fits so well together and is solid compared to my other cars. No plastic tabs that break when you disassemble it. You could take the interior out a dozen times and it will still fit back together and it’ll look new. After years with BMWs, I’m seriously impressed by how much time and money Mercedes invested in areas I don’t normally care about. It’s too bad it didn’t unleash the interior team on the engine; it would probably get covered in leather, but they might have ditched all the rubber tubes!

Vacuum Hoses For Door Locks?

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Caswell: I have no idea where those red wires go! They were there when we got the car. I’m guessing the stereo, but why so many?

Which leads me to the vacuum lines. Didn’t Mercedes know these would be a nightmare in twenty years? Copper wires don’t wear out and they work off the standard battery that the runs the rest of the car, but this was too simple for Mercedes. Instead of wires, they ran rubber tubing through everything to the door locks, the rear trunk, the gas filler lock, and even some seat adjustments in the W210. So what’s the big deal of running some rubber tubing next to the wires used for the windows? Well, the rubber tubing doesn’t run off the battery. So Mercedes needed to install an air pump next to the battery that can suck and blow (create pressure or a vacuum) to operate the different devices. Look at the size of the pump and the various lines coming out of it!

Why run two systems right next to each other when one system could operate everything? Please tell me it’s not about the noise. Meaning: Is all of this because Mercedes doesn’t want the door locks to make a sound? In case someone approaches your car and you want to quietly lock the doors without them knowing? But seriously, why?

What happens if you want to use the locks or vacuum systems after the car is off? Does that pump stay on with the key off? How does that not drain the battery as the lines get old and start to leak? What about that safety thing where your doors automatically unlock after a crash? It looks like Mercedes hid more air boxes and switches under the front fender to address those issues.

Skiklasse Vacuum Box

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It’s such a mess. Almost feels like Mercedes’ cousin owns a vacuum tubing company and they’re doing them a solid.

The Mercedes Has Been…Problematic

Why do I care so much? I’ve tried leaving four times for the West Coast to drive this car on snow and never once made it to the highway. Each time I got a check engine light and all four times it was because of something vacuum related. The final failure (maybe the fifth?) was the MAP sensor itself. It sort of melted. The whole backing came apart and oozed out the sensor. I naturally tried to RTV it all up hoping it was just oil degrading the plastic over the years. It worked for a day or so while driving around town, but the moment I pulled out for the road trip… it was “Check Engine” time.

When we first got the car, I was like let’s change EVERYTHING rubber on the engine. I do this to my racecars because it’s hard to tell when an old rubber line wants to quit. But that’s an easy process on a BMW. I just open the engine tab and select vacuum and order every part number. Or I go to visit FCP Euro and grab a vacuum and cooling kit like this one for an E36 M3:

rcp euro M50 hosekit
Source: FCP Euro

None of this exists for older Mercedes. FCP Euro and Danny Kruger are building these kits out so we can fix our old cars at home, but without the exploded parts diagrams, it’s almost impossible to figure out what needs to be ordered in advance. Even since we started our project, they’ve put up more kits. And now I kind of want their ignition kit…because Mercedes used 12 spark plugs on our car. Why? Because they could I guess. It’s just more stuff to fail in my eyes, but I can imagine the engine burns cleaner with two spark sources. Or maybe their cousin owns a spark plug company too?

Do Enthusiast Cars Lead To Great Support Or Does Great Support Lead To Enthusiast Cars?

All these issues ordering parts makes me wonder about the chicken-and-egg of enthusiast cars. Did we turn certain brands and models into enthusiast cars because we could get the information and parts? Or did the industry respond to our demand and build out the system? I remember buying all my parts at the dealer (or out of the back of a magazine before the internet). But even then, BMW’s were easy to understand and get parts for. Same with my friends who built Hondas. Is that what drew us to build those brands over and over?

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Is that why I can only think of two Mercedes builds on Instagram? There’s the FCP Euro 190E build based on the DTM era. And there’s an ancient one built for the Gambler that transitioned to Hooptiecross and even completed a lap of the Mint 400 this past march!

 

I’m sure there are few others, but it’s bizarre how few Mercedes are built for fun compared to BMW, Porsche, VW, and even Audi. I blame it on the vacuum lines… or at least the reason why someone put them there in the first place.

While frustrating at first, I’ve now fully embraced Mercedes design philosophy. Everything I did to this car can be classified under WHY? Does a wagon need a hydraulic hand brake? Not really. But it is 189 inches long and will need to turn quickly at slow speed on loose surfaces so maybe. Does the handbrake need to be hidden in the center console and operated by the cars original cell phone (see below — more coming soon!)? Nope. But Mercedes did such a good job with the interior that I couldn’t really drill into the center console like some dirty drift car.

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Ski Klasse Hint

Did I need to need to hide all the switches and a volt meter inside the dash? Of course not. I could of mounted a switch panel below the dash like most of the other builds I see. But why do that when I can get all Mercedes on the design and fully embrace the Why? Its also why there’s a CB radio hidden in the dash and a secret switch that activates another totally unnecessary system that I’ve always wanted, but never needed. Until now. More on that surprise system later, because the results weren’t as dramatic as I hoped! I wanted a lot more chaos. So much chaos that when activated, the passenger just looks over and asks… “Why?”

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OldmanBirmingham
OldmanBirmingham
10 months ago

So RealOEM now has Mercedes part diagram. Check it out:
https://nemigaparts.com/cat_spares/epc/mercedes/

Also Mercedes released allot of the EPC manuals for older Mercs. And its wonderful. I get your frustration but I own an E28 BMW, vintage SAAB 900s, 9-5s, had Volvos and Mercedes. The Mercedes are built muuuuch better than any of them. I do find you need to stick to the E-class or S-class though, the other models aren’t really the same. But I absolutely can not stand the newer BMWs when it comes to working on them. They are fragile, leak like a faucet and dont last. I mean, main bearings fail on several of their V8 and straight six models. So I am surprised you covet them so?

Is Travis
Is Travis
11 months ago

I’m very happy I went with a BMW for my late model DIY wrenching daily driver, and glad I did enough research to know exactly what I was getting myself into.

Steven Sims
Steven Sims
11 months ago

You’ve nailed the reason I’ve bought my LAST Mercedes. I’ve been driving them for 40+ years, but the engineers have gone insane to the point the late model versions are unmaintainable.

My old 240D or even my 88 560SL are solid, simple, rugged, and maintainable. Nothing Mercedes has delivered in this century can say the same.

(Don’t get me started on their “Theft Relevant Part” nightmare, where one must have a $$$ proprietary MB diagnostic tool to replace most modules or parts.)

Nope; No more MB for me.

Torque
Torque
11 months ago
Reply to  Bill Caswell

I thought Mercedes was famous for supplying parts for pretty much every model they ever sold? After XX number of years after the model was sold, I thought Mercedes ‘Heritage’ division had responsibility for parts supply? No?

Carlos Seoane
Carlos Seoane
11 months ago

This is a great article!

Mike McDonald
Mike McDonald
11 months ago

As my dear old dad used to say, you only deserve what you sit still for. There are many cars I would have liked to own, but for these insane problems. Old Rolls Royce’s, Mercedes, even Peugeots and all British cars. And I used to work in a British and Italian dealership (did I mention Lancias?) Yeah. Nah.

R4D4R
R4D4R
11 months ago

I used to work with a tier 3 OEM with ties to MB. One of our systems was going in a W222 S class that we had to retrofit. We had the wiring diagrams and where we needed to tap in to their comms systems to make our stuff work. On our diagrams we identified some cable harness named “XYZ” in the docs. Crack open the trunk and peel back all the interior and find the harnesses we needed, and wouldnt you know it, the friggin wires were all HAND LABELED and we easily ID’d the “XYZ” circuit from some German’s perfectly ledgeable hand writing.

Parsko
Parsko
11 months ago

BILL!!!!

Thank you!

I’ve owned an ’06 XiT 6spd Manual for 7 years. Overall VERY reliable. I’m hitting 170k, and it needs love. I am thanking you for pointing me to these resources I may not have found so easily. Also, FCP is a 15 minute drive from work. I’m dropping $$$$ right now because of you.

Is Travis
Is Travis
11 months ago
Reply to  Bill Caswell

FCP Euro and Turner Motorsport are my life savers for parts

Bongo Friendee Harvey Park
Bongo Friendee Harvey Park
11 months ago

> Instead of wires, they ran rubber tubing through everything to the door locks, the rear trunk, the gas filler lock, and even some seat adjustments in the W210. So what’s the big deal of running some rubber tubing next to the wires used for the windows? Well, the rubber tubing doesn’t run off the battery

That’s why they did it that way. They did it for years before that car was born fwiw.

Greg
Greg
11 months ago

I say lean into it. Become the “Singer” of Merc Wagons. Be bold, and take the leap.

Last edited 11 months ago by Greg
Hiram McDaniel
Hiram McDaniel
11 months ago

Jaguar XJ308 chassis, which is the XJ8 from the late 90s into the mid-aughts. Very common failure is the in-tank fuel pump. And the tank is in the trunk, so that’s not so bad, right? I mean open your trunk and work on it, easy.

Oh, wait, I have to disconnect the hard fuel lines from the tank, okay, how hard can that be?

Holy F, I have to drop the rear suspension/differential subframe completely because those f’ing connects are impossible to get to behind the diff.

MikeF
MikeF
11 months ago
Reply to  Hiram McDaniel

The fuel pump died (or one of them – I think it had two) in my 2000 XJR years ago. I don’t recall the guys telling me they had to drop the subframe but I do remember the complaint that “we could have had an engine out of a BMW in the time it took to swap your fuel pump” and something about someone hanging from the exhaust system to get clearance.

Danny Zabolotny
Danny Zabolotny
11 months ago

This is why I run an independent BMW shop here in AZ, and not a general “Euro” shop. Every single time I’ve worked on a Mercedes or Audi/VW I’ve been burned. And don’t even get me started on Jaguar/Land Rover, absolute trash.

FatGuyInALittleCar
FatGuyInALittleCar
11 months ago

In high school my friend had a W201 with that vacuum lock system. We’d push down one door lock when we got out of the car and watch them try to balance the vacuum to get all the doors locked/unlocked in sync.

JumboG
JumboG
11 months ago

Yep, after owning/working on VW/Audis and BMWs, I finally bought a MB W124 and my experience was MB went out of their way to make things more difficult to fix then they needed to be. Oh, and mine did have a straight-6, and somehow they designed the engine compartment so things were still a total PITA to repair due to tight clearances around the engine. Never again – I’ll stick to BMW.

Souper Heaven
Souper Heaven
11 months ago

Why? Because of that fabled German engineering. That’s why. Such a farce.

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