Parts: Front Shock Absorbers

In the past, we have always found that OE manufacturers do not retail parts of the same quality as Genuine parts. Typically they keep the Genuine part production in Germany and then move to a more cost-friendly location to produce their own version. That’s good news for Mercedes’ aftersales systems, but not for the budget of 140 fans. Today, I have the opportunity to introduce some positive news, as you may have guessed. But I firmly believe you didn’t guess it all.

The role of shock absorbers in comfort is crucial. People may tolerate worn joints and failed bushings, but no one accepts bumpy dampers. Here we will focus on the front shock absorber first, because many 140s have self-leveling suspension on the rear axle, which does not have a lot of sense to compared with normal shocks. The front is a very versatile part and is generally unaffected by power options unless ADS steps in. In the same market, the S 280 and S 600 can be equipped with the same front shock absorber.

For the 140 without 214/217 ADS or 482 High Clearance Suspension, 2 versions of front dampers exist. The US and Japan share the same one, which is a relatively unique damper. In EPC, they evolved like this:

• A1403200430, up to A120931
• A1403200930, from A120932
• Both replaced by A1403232200

The technical modifications that occurred near the A120931 were that the suspension was lowered by 10 mm, this included an update of the shock absorbers therefore the appearance of new part number. Although there are two versions related to the period, they have both been replaced with the same new number, the current part number being A1403232200.

The second is the European version. Europe here can be understood as the rest of the world outside the United States, Canada and Japan. The European version can option 482 High Clearance Suspension, which corresponds to a special damper and is not within the scope of today’s consideration. Similar to the US/Japan version, traces of their changes are also left in the EPC.

• A1403200630 up to A120931
• A1403200830 from A120932
• Both replaced by A1403232100

The European version is also applied the technical modifications occurred around A120931. But regardless of US, Japan or Europe, new parts have completely replaced the previous version. This means that old parts are no longer available, cars prior to A120932 will not be able to get original replacement shock absorbers, new shock absorber will lower the height of the vehicle.

Genuine Euro vs US/Japan

Since these two versions have different part numbers, I assume they are different and order both for comparison. The European version will be installed on Octavius and the US/Japanese version will be installed on the JP-spec 1996 S 600 currently in our shop. Only the latest version applicable post-A120931 can be ordered. During the ordering process, I found that the European version A1403232100 is more expensive than the US/Japan version A1403232200.

Both parts are very fresh. A1403232100 was released in March 2022, and A1403232200 was released in April 2023. Before we start planning any more economical options, we should first thank MB aftersales for still providing this critical component, both versions are still available.

The different part numbers raise the question, how different are the two parts? Are they replaceable for each other? There short answer is no. I posed this question to Wolfgang Schoeffel, engineer of Mercedes-Benz S-Class development who has been testing the 140 prototype since May 1987 and who has been at the helm of the evolution of the 140’s suspension components. In his words, different shock absorbers were developed for the US market, and the US version is smoother. Even so, I still wanted to try to discover how they differed.

The shock absorber has a mount on the top which is individually stamped with part number A1403202744 and engraved with a star. Although the part number is given, this part cannot be ordered separately from MB aftersales. The mounts of the two shock absorbers are exactly the same.

Different part numbers are also stamped on the cylinder, A1403232200 and A1403232100. There are corresponding Bilstein numbers below, 02085 1711E002 and 02085 1706E002. The difference lies in the part numbers of these two shocks, 1706 and 1711. A later copy of Bilstein will verify this. If they function exactly the same, there is no point in assigning different stamps, so they may be different.

I hoped not to see any traces of Bilstein on the Genuine part. This is not against Bilstein, I just wish there is more premium. But contrary to expectations, both have obvious Bilstein trademarks, and Made in Germany. If you look closely, you will find that their Bilstein logos are different. A1403232200 is square and A1403232100 is rectangular. I don’t know why they are different, but this is the first difference we found besides the part numbers.

At the bottom, the rubber bushing that connects to the lower control arms is exactly the same. This worries me, are the two parts exactly the same? A worse case scenario is that they were originally different, but today this importance is reduced for MB aftersales and the two parts become effectively the same.

As of now, the static comparison between Genuine parts has little meaning. Feeling resistance with arms is very subjective. Me and two other our employees tried pushing on two shock absorbers each to feel the difference, but we couldn’t came up with agreement.

Genuine Euro vs Bilstein

At this point, I decided to import another player, the most common Bilstein on the market. After previous inspection, we have confirmed that both Genuine versions are made by Bilstein. The Bilstein retail version touted as an affordable replica of the same quality as Genuine part, so let’s see what it’s like.

The only Bilstein B4 front shock absorer in the market has part number 24-017060 or B36-1706, the extra label is affixed to the cylinder. So the first question comes, since there are two Genuine versions, why is there only one Bilstein? Does this mean that Bilstein actually only made one of two version for their own, or that Bilstein only offered one in the market under its own brand?

This Bilstein has been around for a while, 7 years and few thousand kilometers, it has some signs of use, removed from the Octavius, I cleaned up this used part to make it looks fresh. In any case, this shall does not affect the results of the comparison.

On the mount, both two Genuines look identical to the Bilstein, except that the Bilstein does not have a part number or star.

The Genuine shock’s boot has part number A1403260298, which cannot be ordered separately. Bilstein’s boot has the trademark of MPE, which is a company from Italy in the production of precision items, injected and blow-moulded made of thermoplastic materials mainly for the automotive industry. This boot is called D01125 by MPE. Since there is no visible difference in design and quality, it can be determined that Genuine’s boot is also made by MPE.

In the previous comparison, the difference in Bilstein’s trademark was the main cosmetic difference between the two Genuine versions, and here it will help us identify which one Bilstein is offering. Well, Bisltein’s own version has a square trademark, the same as the European version which is A1403232100. Therefore, Bilstein itself retails the European version. In fact, Bilstein and Genuine look exactly the same in this section.

On the other side of the cylinder, the Bilstein version have their own number “02085 1706H002” instead of OE numbers, the “1706” corresponds the 02085 1706E002 on A1403232100. As for the bottom, the rubber bushing is the same, not even any numerical changes.

The conclusions drawn now are:
1.Bilstein OE version=MB Genuine European version.
2.Difference betwen two Genuine still unknown.

Bilstein vs SACHS

For Mercedes-Benz, SACHS is another supplier that cannot be ignored. For example, on the rear axle of the 140, SACHS manufactures self-leveling strut, but its presence on the front axle is indeed not much. At present, SACHS belongs to ZF and has nothing to do with Bilstein. They can be regarded as competitors.

SACHS’s 140 front shock absorbers are no longer so popular on the market. I tried hard to find an NOS pair. Its packaging was a bit shabby and there is no information to tell when it was produced, perhaps not too old. Part number on cylinder is 312 264.

SACHS is significantly different from all Bilsteins. Maybe the mount is somewhat similar, but the parts below are not. The SACHS boot is installed in a different position, it does not cover the stop buffer and therefore extends downward some. The boot itself is also different.

This difference is somewhat surprising. I don’t know why, but apparently it’s not a good idea to expose the stop buffer to the environment. Both dryness and moisture will age it faster. Usually broken stop buffer are one of the reasons to replace shock absorbers, they will break down before the hydraulic part.

Since we are still looking for similarities between SACHS and Bilstein, so it is completely non-existent, nothing is similar anywhere. We have confirmed that Bilstein is the OEM, so did SACHS ever manufacture front shock absorbers for MB? There is a SACHS in front of me that is completely different from other OE parts. Is it one of the previous OE versions, or is it an approximation made by SACHS itself?

To make the comparison more meaningful, all Bilstein boots have been removed. This shows Bilsteins’ stop buffer, which has an entirely different internal structure than SACHS. However, the size of the shock absorber and the relative position of the parts are similar, which are two completely different solutions to the same problem.

As of now, the positive side is that Bilstein 24-017060 can completely replace A1403232100. In my resources, the cost of Genuine is three times that of Bilstein, so if we have a European version to work on, we can use the Bilstein with same quality and low price with complete confidence.

But the above information still cannot determine any technical differences between A1403232100 and A1403232200, we don’t know if the US/Japan shock absorbers could also be replaced by affordable Bilstein. Also, the idnentity of SACHS is unknown. To see as many details as possible, I put all four shocks into the X-ray.

Although it seems from several of the X-ray photos, there are some subtle differences among the three Bilsteins. But a total of more than a dozen angles were scanned, they proved to have no visible difference. Located below are A1403232100 and A1403232200.

Although there was no progress on Bilstein, X-rays revealed the SACHS stop buffer, part of which was hidden in the boot. Comparing the buffer shapes of Bilstein and SACHS with technical illustrations, you will find that the buffers of technical illustrations (from the earliest cars) are more similar to SACHS. Anyway, on some early factory stuff and on low mileage early cars we didn’t find any approximation of SACHS.

The remaining question is the difference between the US/Japan and Europe versions, so I consulted Jeffrey Miller, who was Senior Staff Engineer in Mercedes-Benz North America from 1981-2006, familiar with 140’s suspension and all the rest. He recalled that the difference was in the internal valves which control compression and rebound in the shock absorber which resulted in a softer, more comfortable ride quality at the expense of high speed handling for the US market cars. The nozzle of the valve itself is small, thus the much smaller difference is not quite detectable through the X-ray I have.

Combining the different trademark shapes with the testimony of two former Mercedes-Benz engineers leads to two conclusions:
1.Europe shock absorber is technically different from US/Japan.
2.Bilstein 24-017060 cannot replace A1403232200(US/Japan).

For the sake of authenticity, if you are holding the US or Japan version, it is best to order the expensive Genuine part from the dealer to ensure factory performance. Ironically, all the Bilsteins I see at US parts retailers are 24-017060 for the European version, incorrect shocks are being installed every moment. I’m very pleased that the JP-spec 1996 S 600 currently in our shop will get the correct shocks and we will continue to do so on future projects.

Please note that all parts are brand new and purchased in recent times (2023), they represent the current status of these manufacturers only and do not imply anything about the past or distant future.