[chair]

Hello everyone,

Here is a quick update on the restoration journey of my W123 230E — a car that’s turning out to be even more interesting than I first imagined.

VIN Decoding:
WDB: Mercedes-Benz (Daimler AG)
123: Series Code
223: 230 E M102 (Sedan & Type Designation)
2: Right-hand drive
2: Automatic gearbox
XXXXXX: Production serial number

What makes this car particularly special is that it seems to fall right in the transition period for the W123:
• It carries some pre-facelift styling details
• But runs the newer M102 engine with Bosch K-Jetronic fuel injection

Is it fair to call it a “best of both worlds” configuration? I certainly think so, and I’d love to hear what you’ll think.

How the Journey Started
Interestingly, this W123 has had quite a story even before I entered the picture. Jatin sourced the car back in November 2024 — it was sitting in Madras (Chennai) in less-than-ideal condition and had it transported to Bombay to save it.





It caught his eye for one big reason: it’s a rare early 230E with the M102 engine.

At first glance, the car appeared to be a beige white shade. But while unloading, a few fallen-off trim pieces revealed a hint of China Blue underneath.


That small detail led to some digging, and after locating the original paperwork and also via the cars Datacard, it was confirmed:
This car was factory-delivered in China Blue! With the Sunroof, Autobox, Manufactured in 1979 at

Since then, Jatin’s team has been working meticulously through the bodywork, sorting all the rust out properly — no shortcuts. The shell is now solid, and we’re finally moving toward the next big phases.








Current Stage:

• []We’ve decided to rebuild the engine and gearbox along with the entire suspension system.
  []Some critical parts have been ordered (some still in transit).
• The focus for the next month will be to get all mechanicals right first — before we touch the cosmetics.

A Special Thanks to Jeroen
After Jeroen’s very helpful message, I double-checked the engine details on my car. Mine is indeed a 230E with the M102 engine and Bosch K-Jetronic fuel injection.

It’s a mid-to-late 1979 manufacture, registered early 1980 — so it falls perfectly into that interesting transition period.

Also, thanks to Jeroen’s note about the simplex chain and tensioner issue on the M102, I’ll be adding a new timing chain and tensioner replacement to the mechanical overhaul list while we’re rebuilding the drivetrain.

I also spent some time going through Jeroen’s W123 fiddling thread — it’s genuinely a treasure trove of practical DIY tips! Definitely bookmarking it as a reference through this build. Thank you again, Jeroen, for taking the time to guide me through this process.

I’m excited to share updates once the mechanical work starts coming together properly!

⸻
Your Opinions Needed: Wheels and Tyres
There’s one point Jatin and I keep debating — and I’d love to hear what you all think.

Originally, the car was sold with Bundt alloys (14 inchers).
Now, 14-inch tyres are getting tougher to spec properly. There are replica 15-inch Bundts available, which is one option.

But… I’m smitten by the classic look of body-colour steel wheels with hubcaps.
I’ve managed to source a 15-inch steel wheel set, but the rims are 6J wide.

• 175 width tyres would fit easily but might look too narrow for the car.
• I feel 195 width tyres can still work well on 6J wheels without spoiling the stance or period-correct look.

What do you guys think? Would 195/65 R15 work cleanly on 6J steel wheels without messing up the feel or aesthetics?
Or should I go back to replica Bundts and call it a day?


Would love your opinions!

⸻
Thank you again for being part of this journey — excited to hear your thoughts, and I’ll post more updates as the build moves forward!

—
Project China Blue | 1979 Mercedes-Benz W123 230E

[Jeroen]

Yours must be one of the very first 230E with the M102 engine. Does your man have experience overhauling the Bosch K Jetronic?

I suggest getting the most elobarate rebuild kit on the market and replace everything. Lots of info on the K Jetronic on various forums and YouTube. The system was used on quite a few other brands of cars, noticeably Porsche.

As far as I know all parts are still available, which is more than. Can be said for the Stromberger Carburettor on my M102 engine.

Irrespective of size I like both styles of wheels. Although I always prefer the Bundt on the coupe and the sedan with the body colour hubcaps.

I will be following this restoration thread with interest, keep it coming!

Jeroen

[DudeWithaFiat]

Amazing. All the best of luck for the restoration. As for the wheel caps, both look good, but my vote goes for the body-coloured hubcaps.

[G-One]

My choice would be 195 on 6J. Would be sacrilege to remove the 6J.

[car love]

Awesome!! My choice would be the body colored wheels. They are so classy. There is a W123 Guru here in Bangalore. He could be of help if needed!

[chair]

Project China Blue | W123 230E Restoration Update
1979 Mercedes-Benz 230E (W123)

Hello again folks,
Time for a quick update on my W123 — things are really moving now, and the car is finally starting to feel more “real” than “project.”


Bundts vs. Budget vs. Purism
I’ve decided to stick with Bundt alloys, as originally specced on the VIN.
That said — I’m still debating whether to go 14” or 15”.

• 14” Bundts are VIN-correct and more affordable (around ₹50K for a set)
• But Michelin tyres — also part of the original spec — aren’t available in 14” anymore
• 15” replicas would allow me to run proper Michelin rubber again and improve the driving feel
• But the landed cost of the wheels is around ₹2.25 lakh, which feels hard to justify

So either way it’s a compromise: Do I stick to factory correct wheel size and not on the rubber, knowing I’ll need to compromise on grip and ride quality? Or stay brand-correct on tyres with a slightly larger wheel that is visually correct but costs a small fortune!

Still debating it — open to thoughts from the purists and the practicalists!


Mechanical Progress

• Engine, gearbox, and suspension rebuilds are in full swing
• All bushes, dampers, steering and suspension linkages have been replaced
• Suspension and steering components are being properly painted and finished
• Every nut, bolt, bracket and washer is being zinc plated to factory spec
• We’re not aiming for “decent” — we’re working to ensure this will be the most detail-accurate W123 restoration in the country

One Unexpected Setback
During teardown, we found that one of the crankshaft lobes was slightly bent. We’ve ordered a brand new OEM crankshaft — now en route.


Timeline

• All pending parts from across the world are expected to arrive in Mumbai by mid-June
• Mechanical reassembly (engine, suspension, drivetrain) will follow
• Then we move into cosmetics, trim detailing, and final tuning
• If all goes to plan, we’re hoping to have her on the road by end-July or early August

These aren’t glamour shots — just raw, greasy glimpses into the mechanical side of the build.
But for those who like the gritty detail, here’s a peek at what’s been happening under the skin.

[ajmat]

Hats off to you, you are literally remanufacturing this car. Keep us posted!

[Jeroen]

Great work!

Just a couple of practical pointers on the steering set up. Many W123s suffer from steering play. If the ball joints are all good you need to check the slave steering box. It can be easily re-sleeved.

However, the most prone wear component is the steering box itself. And mostly because mechanics adjust the play by feel. Yes, it will tighten up the box a bit, but it will make the problem worse over time.

The Mercedes workshop manual stipulates a maximum of 2 cm play measure on the rim of the steering wheel. Almost all W123 I come across have more.

The official adjustment procedure requires some very special tooling, in particular a torque wrench with a very low setting.

I will post the relevant pages from the American Mercedes workshop manual (so it’s in English).

Once a steering box has been adjusted manually, which just about all of them have over time, you can’t cure the play anymore and the box needs a full overhaul.

Jeroen

[chair]

Originally Posted by Jeroen

The Mercedes workshop manual stipulates a maximum of 2 cm play measure on the rim of the steering wheel. Almost all W123 I come across have more.

The official adjustment procedure requires some very special tooling, in particular a torque wrench with a very low setting.

Thank you, Jeroen — as always, your insights are invaluable.

We’ve already pulled the steering box and are working through a full rebuild of the steering system. At the moment, the engine block work is underway, and we’re rebuilding the transmission using a master kit for the 722.1 — it’s the 4-bolt pan version, compatible with the 722.0/1/2 family. That’s come in from Cobra Transmission, and we’re doing a full overhaul rather than just seals and gaskets.

The suspension work is nearly complete, and the steering system will be the final major mechanical element — though that too is already in progress.

Your note about the 2 cm play tolerance and the low-torque wrench requirement is really helpful, I have not come across that level of specificity — and it reinforces why so many W123s end up with vague steering feel despite having “rebuilds.” Definitely an eye-opener.

We’re going to make sure we follow the right method when we get to final adjustments. Would love to go through the manual pages you mentioned — that kind of detail is exactly what makes the difference between a quick fix and doing it properly.

Thanks again for sharing your knowledge so generously — it’s genuinely shaping the way we approach this restoration.

[Jeroen]

As promised, some information on the adjustment of the steering box.

There are several variants of the steering box across the W123 range.
They are identical in the way the final adjustment is made via measuring the torque on the Steering Wheel.

As I mentioned, the maximum play permitted is measured at the steering wheel circumference:



Here is the procedure for adjusting the play:











Note that this measurement and adjustment need to be done with the pitman arm removed and the engine idling!

Notice how you should be able to see an increasing torque as a function of the Steering Wheel angle. Also, notice that the torque is stated in Ncm. That is Newton Centimetres, not Nm (Newton meters).

You mentioned that you are already in the process of overhauling the complete Steering box? The above is the final step of the course.

But overhauling a Mercedes Steering Box is not for the faint of heart. I had mine overhauled three times. All steering box specialists. But the first two times it developed play within 10000km again!

I finally found a guy who really knows what he is doing. Or rather, somebody who just follows the official procedure to the letter and has the equipment to do so.

Because you need some special tools and a set of special (thrust) washers in different sizes!

I am attaching some images of the various steps, and you will get a feel for how delicate this is. Some parts need to be checked against a 3 Ncm (Newton centimetre) torque!!

















A summary of the most important torque specifications, all in Ncm!



I have various sets of W123 workshop manual. Obviously, I have the original German one. But it is in German, Duh. Even if you don’t speak German it can be immensely useful, because it has lots of detailled drawings.

If I were you I would try and get my hands on the American Manual. All images here are from the American one.



You should be able to find a good set on EBay.

You might even find one in a digitally scanned format. Or try this one:
https://www.emanualonline.com/cars/m...mo-213854.html

I have bought a lot of my digitally scanned manuals from them!

Even a new W123 Steering box feels a bit vague around the centre position. It is even allowed a bit of play, can’t be helped. If you follow all of the correct procedures, you should end up with a reasonably tight steering car. If you don’t, it will become a bit more sloppy over time.

These cars are mechanical marvels. As you can see a lot of thought and ingenuity went into designing and manufacturing and maintaining them. It also means that they can stand quite a bit of abuse. Whenever I come across a W123 I always ask the owner if I can feel the steering wheel for play. I have got a decent feel for it over the year. Most are way over that 25 cm. Almost all are adjusted by hand and feel. Dead loss, can’t be fixed anymore.

Good luck

Jeroen