FD,

What part number and source did you use? I planned to install V36-0361 HD's that were on my wagon and found distinct differences between the Cab's OEM (I believe) that would not allow me to install them. I could not find a unique number in any Bilstein spec sheets. As shown the differences are the upper hub mount hole for a larger bolt, height of body, and length of stroke. I discovered this after struggling to get the top nut off the unique vibration mount...

BTW, here is the damper explanation

 

pifcat2 -

Thanks for your post. You're right, I did notice some differences.

I noticed the difference in stroke and body height, but assumed that these differences would not be an issue for me with a non-lowered suspension because even though the Bilstein has a longer stroke, when installed on the Cabriolet, the strut would just operate over a short portion of it's travel. Since the strut valving seems to be linear, where it operates within the range should not matter as long as the top extension and bottom extension limits are larger that stock and the top extension is not so large so as to allow the springs to escape (which they don't). Hmmm, I wonder if the valving is indeed linear in that regard . . . My understanding is that the Bilstein Sports have the same valving as the HDs but also have a travel limit stop to prevent issues like escaping spring on cars with lowered suspensions. As for the taller body, this could cause an issue with "bottoming out", but again, on a non-lowered car, I didn't think there would ever be that much travel. Now that I think about it, the lower strut mount spacers (which are exclusive to the Cab) shorten the strut mount to top-of-strut distance, so there in fact, may be a potential bottoming issue.

I did not, however, notice the difference in bolt holes because I used the Bilstein supplied hardware kit which (unknown to me at the time) included a slightly smaller diameter bolt for the top knuckle connection so they installed easily. Interestingly, I checked the MB EPC and the steering knuckle that the strut bolts attached to is the same across all W124's (in fact it's the same across many models from 1990 until 2002!). This means that the hole in the knuckle is larger than the Bilstein provided hole for all W124's, so one should not be able to use the OEM bolt with a Bilstein strut for any '90-'95 W124, including the Cab. In this sense, Bilstein HDs for the Cab are no different than Bilstein HDs for any other W124. But, while the Bilstein hardware seems to work, now that I know about it, I am a little concerned about the extra "slop" which this design permits.

BTW, I bought a pair of Bilstein comfort struts to replace the Bilstein HDs - they were just too stiff for what I want this car to be (I will be posting the HDs for sale soon). The Comforts are the same as the HDs, including the smaller bolt hole. I pieced together the info to order the HDs and the Comforts from various websites and from various incarnations of the Bilstein catalog (their website is tantamount to worthless). Interestingly, the websites I have checked (peachparts, europartsdirect) all show the stock replacement (Sachs) struts to be the same for the Cab and the Coupe. Peachparts shows the Bilsteins to be the same for both cars as well.

This is all very interesting. The bolt hole worries me, as does the linearity of the valving. As I posted previously, in many cases it should be possible to design a universal or near universal replacement part that in backwards compatible to the many OEM variants. But it's beginning to look that that may not be exactly the case with the Bilsteins.

Does anyone else have any thoughts?

- FD

 

So EPC indicates all W124's have a larger hole for the larger bolt but most use the smaller bolt and holes on the struts? The Cab strut also had the larger hole. I measured 0.584" vs. 0.505" holes in the two struts. We need to measure non-Cab hub upper mount holes, I never noticed it being larger.

I briefly considered drilling the HD strut hole larger but decided to reinstall the old strut until I sort this out. If I were to install the HD I would use the smaller bolt with a bushing the length of the bolt but it would have to be precise or the bolt won't tighten. I'm curious why they used a larger bolt and that it doesn't seem to be documented.

Here is the Sports & HD length difference.

 

I re-checked the EPC today and last night I seemed to have been suffering from analcephalosis (the condition of having one's head up one's butt - anlacephalitis is the red face caused by the mistakes one makes when one suffers from analcephalosis). I checked things a little more carefully and found that there are two different knuckles and two different bolts for the strut. Sorry about the error.

Today I found the following:

Cabriolet (124.)
400E E420 (124.034)

Use:
N000912014077 Strut bolt
129 330 0220 Left Steering Knuckle

300E (124.032)
300CE (124.051)

Use:
N000961012210 Strut bolt
124 330 0420 Left Steering Knuckle

Presumably the other strut bolt listed on the EPC is a smaller one that matches the hole in the Bilsteins struts. This seems to confirm a post wherein someone stated that the Cabriolet uses the same struts and the 400E/E420. This seems to make sense in that I believe there are other parts the MB took from the 400E/E420 series (presumably because of the higher weight in the cabriolet). Is there a Bilstein strut of any type (HD, Comfort, Sport) out there for the W124 with the larger hole? Perhaps there is a Bilstein series specific to the 400E/E420 - this would address the "hole" issue. But I'm not sure where this leaves the strut question overall as the body length/stroke issue may still be there. I agree with you that I would use a spacer rather than drill the struts.

For now, I will keep the Bilstein comforts in place (with said spacer) until more info surfaces.

- FD

 

Is there a noticable difference now with the comforts in place. Is that shake you are experiencing gone now??

Can you check to see what the details for the E500 500E are please??

Great info Floobydust!!

 

Is the spacer in the kit a bushing that goes in the knuckle hole for the narrower bolt? That would work fine with the strut's smaller holes.

 

Unfortunately there is no spacer included in the Bilstein hardware kit. It seems to me that inclusion of such a spacer would make the struts truly all-model compatible at least with respect to the bolt size problem. I plan to machine a pair of spacers for my car myself. I think that if you get all three bolts in place (but still loose) and then tighten the two lower bolts, the smaller upper bolt will at least line up in the center (due to the alignment pin on the knuckle). There could be problems, however, if the reverse is done because the upper bolt will be off-center due to the strut spring force. Tightening the upper bolt first will clamp the strut bracket to the knuckle at the wrong angle (because the hole is off center) so when the lower bolts are tightened, the strut bracket will have to bend to match the improper knuckle to strut angle. This could permanently damage the strut and throw off the alignment.

I have attached a section of the German Bilstein catalog and the US Bilstein catalog and they both show that the V36-0361 HD is applicable to almost all non-sportline W124s. Things get confusing when it comes to the comfort struts as the US catalog differs from the Euro catalog with the US recommending either the V36-0190 or the v36-4050 while Europe goes with the V36-0185. I have the V36-0190 on my Cab, but the thing that is interesting is that (in the US) all struts use the same hardware kit which means they all use the smaller bolt! Interesting.

I am still really surprised that these issues have not come to light before now.

- FD

 

Thanks.

As for the shake, it is still an issue. I'm still working on some things (and may try the old MB OEM struts again). I have replaced almost everything that moves or is made of rubber on the front end yet the issue persists. I will have an update once I finish all the things I want to try. I'll post the results.

The E500/500E is different yet (a mixture of both). The EPC calls for:

A129 330 0220 Steering Knuckle
N000961012210 Strut Bolt

- FD

 

Hardware kit just includes the new bolts and washers? When you make the bushings for the upper knuckle would you be willing to make me a set? Hopefully there is bushing stock with correct dimensions so it would just need to be cut to length.

I've had no problems aligning the strut. I support the LCA with a small jack, hand tighten the lower bolts, then insert the bolt on the upper knuckle, then the nut on top of the strut. Tighten and torque...

 

Yes, the kit includes only a new, smaller upper bolt, two new washers, and a mating nut. It also includes the two lower bolts/washers as well.

Yes, as long as I have the lathe fired up, I will make some extra sets.

It looks like you have the tightening sequence correct, although I would recommend jacking up the car, placing a block or jackstand under the LCA, placing a shorter "safety" jackstand under the car, then lowering the car slightly with the jack to compress the spring/strut. This is just for safety reasons because jack failure (or accidentally letting the jack go too low) with your method could result in the road spring being released. If you do it the way I described, jack failure will simply compress the spring a little more.

-FD

 

Just a little update. I called Bilstein US to ask about this issue and, as luck would have it, the person I spoke with drives a White/Gray 1995 E320 Cabriolet! He did not have access to enough information to answer my questions (12/14mm bolts, stroke/body length), but promised to find someone who did. Within a couple of hours I got a call from a German engineer who had access to all the engineering drawings for the Comfort, Sport, and HD shocks they sell for the W124. He confirmed that all of them have a 13.5mm upper bolt hole which is for the use a 12mm upper bolt. He was familiar with the W124 production and indicated that 50% of the OE struts were supplied by Bilstein and 50% were supplied by Sachs-Boge. He said he would email the OE division (who has the drawings for the actual OE struts) and get back to me. He said it might take them up to 10 days to answer.

Sometimes it's better to be lucky than good.

- FD

 

You're a bl00dy diamond Floobydust. I'd be very keen to get proper like for like properly Engineered OE replacement shocks for my Cabriolets. But at NZD$900.00 each for the rears, and God knows what for the fronts from the Dealer, you will understand I am not so keen to go for the genuine article from MB.

Is there any way of knowing what type is on my car, is there a Bilstein marking somewhere or can they tell by production date, model type, chassis number?? Is there any way you could enter into a discussion with the Bilstien Engineer to come up with an exact correct replacement for a Sportline Cabriolet & not a “will fit/close enough” type. By that I mean not only the hardware issues but also the damping / rebound rates and performance criteria of the shock. I'd like a proper exact match for these, not a "try these they are great" type of selection criteria. Cabs are fussy, and deserve a properly Engineered solution if you are not going with a genuine MB supplied unit. Any chance of sounding them out??

 

Great contact! So all of the Bilsteins are designed with the smaller hole? Did they ignore that the cab knuckle uses a larger bolt? Can you also ask them which model is best to match the OE stroke length?

 

WDB124066 -

I hope to find out the answers to these questions or at least find out what the compromises are for the aftermarket units. I will also ask about how to determine the difference between Sachs and Bilstein of the OE parts. From my experience (which is admittedly, limited) parts made by Sachs have the Sachs name on them somewhere and parts made by Bilstein have no manufacturer ID. Interestingly, on my new Bilstein aftermarket struts the place for the MB logo on the plastic stop the holds the strut boot in place is clearly visible in the same place as the old OE struts which makes me suspect even more that they are Bilstein.

- FD

 

F D

Not that it applies to you, but for any early 124 readers the OEM shock was probably Boge which then became Sachs/Boge.

Bilstein became an OEM supplier midway through the 124 production run...

Question to you....was your car ever in an accident ?

 

I can find no evidence that the car was ever in an accident. All the paint is original and there is no indication that any of the suspension or body parts have ever been replaced. There are no dents in the undercarriage or any impact marks on things like the cross member, etc. The only thing that was not "as-from-the factory" is one of the aluminum diagonal braces was missing on the left rear side when I first bought the car . I ordered a new one from MB (the last one in the U.S.!) before I even drove the car. It bolted up exactly as it should.

 

That's encouraging !!!!

Assuming wheels, tires are balanced and true and alignment was done correctly on a four wheel machine then maybe look at your flex discs, drive shaft support bearing and brake rotors along with everything else back to the differential......



AS crazy as it sounds, what are the condition of your brake rotors ?

 

I did some measurements over the weekend on the struts I have for my Cab and found the using any of the Bilsteins on a Cabriolet is going to result in the loss of 22 mm of upward suspension travel with the stock springs! This is because MB had to use a spacer to lower the tops of the struts mounts to permit clearance for the infamous vibration absorber. They in turn specified a shorter strut body for the Cabriolet. 22 mm just happens to be the thickness of the extra spacer so the overall suspension travel could remain the same on the Cab as on the other W124 sedans/coupes. I have attached a chart with the measurements I made. Note that N/A means I did not measure the value and italics means that the data is estimated.

How anyone successfully runs these struts on a lowered Cab is beyond me - minus 22 mm for the body, another 25 - 30 mm for the lower springs and you're down to ~70 mm of total suspension travel and probably less than 35 mm of compression travel. These cars must be running completely on the bump stop!

- FD

 

I got a voice mail from the Bilstein engineer today. He said the the 14 mm bolts were only used with struts made by Sachs, which by implication, means that Sachs made all the struts for cars that used the knuckles with the larger 14 mm bolt hole. These seem to be the "special" w124 series cars such as the cabriolet and e420/400e. He said that the OE division is consulting the Mercedes to determine if using the 12 mm bolt on these cars is acceptable. He will call back when he knows more.

- FD

 

Great info man, thanks for putting in the time researching this. I think I'll just stick with the cabrio/wagon specific Sachs-Boge that I see on autohausaz in that case. When I lower the car in the future I will probably use Bilstein and hopefully this issue will have been resolved.

 

I scoured the other forums but found nothing about the strut differences. Maybe most have not replaced their struts or just used the smaller bolt and taller aftermarket strut. Koni may know something...

 

After taking a look at the MB R&R procedure I've decided to drill the Bilstein comfort struts on my car and install the 14 mm bolts. The MB document describes the process of tightening the lower two bolts first, then the upper. It also clearly states the torque for both the 12 mm upper bolt and the 14 mm upper bolt (depending, of course, on which one your car has). The torque spec for the 14 mm is 200 Nm, nearly double the 110 Nm for the 12 mm. The upper bolt plays no role in "locating" the strut - that is done by the two lower bolts and the metal teat on the knuckle. It's sole purpose is to provide a clamping force to create a structural triangle with the bottom bolts. MB felt that it was important enough to have extra clamping force from the increased torque on larger bolts that they produced a different knuckle, strut, and bolt assembly for the heavier cars (400, 500, Cab). Therefore, it's important enough for me to drill the struts to maintain the integrity of that design (I used a 9/16" (14.3 mm) bit which gives just the right amount of clearance for the 14 mm bolt).

The MB procedure also clearly shows the spacer that is present only on the cabriolet. My thought here is to order the bump stop from the sportline suspension (which should be designed for the shorter suspension travel on the sportline) and give live with it. The roads are bad here in New England, but not so bad I'm bottoming out all the time.

Interestingly, this issue is not unique to Bilstein. I checked the Koni, and KYB manufacturer's website and they do they same as Bilstein - one strut, all cars. Clearly the aftermarket strut manufacturers either don't know about or don't care about this issue.

- FD

 

Looks like these guys had the same issue with the strut hub mount, drilled open the bracket hole...

 

Edit.

 

Hello, same problem. How do you describe experience with Bilstein Comfort Shocks on w124 cabrio? Thanks for any advice.