Author Topic: Urethane suspension bushings - NOW READY! (Read 15117 times)

wwheeler · « **on:** February 03, 2020, 15:32:27 »

I have a unique opportunity to buy tooling to produce urethane bushings for the W113. They also fit the W111, W108, W109 etc....These are tools that have been around for close to 20 years. Before I make that investment in the tooling, I was curious if there is any interest now. The bushings would mostly be for the trailing arm, subframe spring and sway bar.

These parts have not been available for a few years and mainly due to lack of interest in selling by the old vendor. I realize there will be a limited market for these, just curious how limited.

Thank you,

Wallace

mazmonza · « **Reply #1 on:** February 03, 2020, 16:30:43 »

I am using these at the moment but would like a spare set .

Maurice

pedrocamp · « **Reply #2 on:** February 03, 2020, 17:22:20 »

Interested!

Pawel66 · « **Reply #3 on:** February 03, 2020, 17:31:56 »

Quote from: mazmonza on February 03, 2020, 16:30:43

I am using these at the moment but would like a spare set .

Maurice

I am curious: not experiencing more vibrations? The car should be "more stiff", they are quite durable, but my W463 experience was - a lot more vibrations transferred to body.

dirkbalter · « **Reply #4 on:** February 03, 2020, 17:56:12 »

Interested as well.

Benz Dr. · « **Reply #5 on:** February 03, 2020, 18:06:28 »

There was a guy in California that was making an entire set; trailing arms, sway bar, rear axle trailing arms, front suspension,and maybe more. I think the company was called Cox Racing Bushings. If they're not around anymore I'd say give it a try.

wwheeler · « **Reply #6 on:** February 03, 2020, 18:45:02 »

Cox isn’t around any more but I know where they are

I realize the ride will be stiffer and most do not want that. But some do, which is why this product has been sold in the past in limited quantities. Thanks for the input.

lreppond · « **Reply #7 on:** February 03, 2020, 19:49:34 »

Interested.

Garry · « **Reply #8 on:** February 03, 2020, 20:24:19 »

Am interested also

mazmonza · « **Reply #9 on:** February 03, 2020, 23:12:26 »

I haven't noticed vibration but the ride is firmer, I also have stiffer Olsen road springs.
With this combination I do get flatter roll free cornering but feel the road more

Maurice

Benz Dr. · « **Reply #10 on:** February 03, 2020, 23:18:03 »

Ride is only a bit stiffer but the handling is much improved. I have a 22 mm sway bar on my car so it handles quite a bit better than a stock 230SL.

Cees Klumper · « **Reply #11 on:** February 03, 2020, 23:59:13 »

I bought the set from Cox Racing waaaaaaay back, probably around 2001. Fitted everything (mostly sway bar bushings I think) but for the 'donut' bushings under the rear trailing arms I quickly switched back to rubber because of the significant increase in vibrations.

wwheeler · « **Reply #12 on:** February 04, 2020, 00:59:16 »

Was that the front mount (frame) or rear mount (axle) for the rear training arm? I have been told that the front mount (frame) benefits greatly from urethane where as the rear (axle) doesn’t as much and can cause vibrations.

JamesL · « **Reply #13 on:** February 04, 2020, 06:36:24 »

Interested

VincentR · « **Reply #14 on:** February 04, 2020, 07:56:07 »

Interested

VincentR
280sl - France

pedrocamp · « **Reply #15 on:** February 04, 2020, 12:30:00 »

Wallace,

Do you know what durometer urethane was used in the original moldings? What durometer Cox used? Do you have various urethane durometers available from your proposed supplier? Compliance and transmitted vibration could vary according to selection.

russelljones48 · « **Reply #16 on:** February 04, 2020, 12:56:21 »

count me in. can someone tell me why the rear bushings seem to generate NVH that is unacceptable? I've used aluminum body mounts and urethane bushings in other vehicles of the same vintage with no detrimental effects. I actually find it tightens up the car and reduces noises from body to frame flex.. urethane does need "special" grease - just a very sticky grease to avoid squeaks but I'm intrigued as to why it might change the NVH that much?

wwheeler · « **Reply #17 on:** February 04, 2020, 16:26:00 »

Thanks for the replies. I don't know now, but will be able to determine exactly what hardness was used in the past. I will actually be the one making the new parts from the original tools. So I can vary the hardness a bit if needed. I am still doing some background on the tools and such, but wanted to see if anybody has interest. I would say from the brief couple of days here, that there is sufficient demand.

pedrocamp · « **Reply #18 on:** February 04, 2020, 18:14:10 »

Good to hear you see a market and will proceed. It may be that the urethane durometer used could be application specific, a compromise of compliance and vibration transmission... and of course durability. For example a bit harder durometer for the forward joint of the trailing arm and softer at the rear joint? Or vice versa? In testing wide swings from 60 soft to 90 hard would be easier to feel than 70 to 80, especially in an un-instrumented road car. Manufacturers nowadays vary compliance and vibration isolation with holes or voids (sometimes fluid filled) in the mounts or joints. My Honda Odyssey has electronically controlled motor mounts that change their vibration isolation frequency range when the engine is either on 6 or 3 cylinder ECO mode. Most manufacturers use compliance as a tool to keep suspension geometry in check as Porsche famously did with the Weissach axle on the 928 to eliminate lift-throttle oversteer.

FGN59 · « **Reply #19 on:** February 04, 2020, 22:32:09 »

Might this be a case of the more we learn, the less we know? as I believe a famous scientist once said (could have been François Jacob, or even A. Einstein, or some other bloke on par with those guys).

This thread, like many others, brings to the fore some truly fascinating aspects of mechanics and roadworthiness, all mixed and sometimes conflicting as they rightly should be (no true performance comes easily), but now I don’t know what to think anymore. At the beginning I thought I might be interested in those bushings, but the more I read, the less I understand... $:-\$

My previous ‘oldie’ was a 1963 Jaguar Mk2 (albeit with a 4.2L, 270HP engine), a kind of a beast, really fun to drive but requiring you to really pay attention to the road, and a bit of a ‘hard’ ride. The softness of the 280SL is a surprise (a nice one, sort of), but I wouldn’t mind a bit of a tighter (stiffer) ride, as long as the car remains as homogeneous as it is now (front/rear balance), for it is quite remarkable as it is. What to do? Stiffer bushings, thicker sway bar?

pedrocamp · « **Reply #20 on:** February 05, 2020, 12:42:50 »

I would hazard to guess you won't see a detectable balance change switching to urethane bushings on both ends of the car. You will improve the efficiency of the front anti roll bar with a hard durometer urethane by reducing the compliance which could increase understeer by a small amount but you may need to be Rene Arnoux, Alain Prost or, in the modern age, Charles LeClerc to feel the difference... but of course I am not questioning your driving skill! I am sure there are those on this forum more knowledgeable than me but you may only notice increased responsiveness, a bit "crisper' handling, due to the reduced compliance in the suspension (depending on durometers chosen... harder more, softer less) but you may feel increased transmission of vibration - sharper frequencies as the softer durometers of the OE rubber bits are not there to absorb or dampen it. Urethane bushings can be noisy, squeaky, as Russell mentioned and should be greased if used in rotational joints.
A stiffer front anti roll bar will change the balance of the car (usually towards more understeer or push) unless coupled with the addition of a proportionally sized rear bar. If balanced the bars will flatten out the ride, less weight transfer to the outside tires, but increase the chance that you compromise traction in a bumpy corner since you are increasing spring rate in roll. Spring rate changes, proportional or not front to rear, can change balance and responsiveness. Reducing compliance in any of the system will make the car less "cushy"... usually, but more controlled. For a race car the engineers try to reduce compliance as much as possible to increase suspension and chassis control unless that compliance is beneficial. Of course a dedicated race car will rattle out your dental work compared to a road car.
In the end its a compromise on how you want the car to feel, one driver may like the balance of a particular car where another finds it unbalanced for his style. Again I don't want to try to appear as an expert on these cars or suspension setups in general, I am sure there are those on this forum that could recommend specific modifications to the suspension and chassis to improve responsiveness without losing too much of the comfort that Mercedes engineered in.

russelljones48 · « **Reply #21 on:** February 05, 2020, 18:23:07 »

Don't let Pedro fool us with his modesty - he's been around performance cars for quite a while now and extends his job as his hobby.. His advice is good and changing out the various "Rubber bushings" in our cars will ultimately be a personal choice of preference. Here's what I remember of the history of "Rubber" suspension/chassis bushings. I believe they came to the forefront in post-war cars and were used by engineers to eliminate NVH issues in part because they believed the public wanted a "smooth" riding car.. for us Americans , remember those 60's land yachts whose steering and suspension was so isolated from road feel that it was hard to tell for a while if you were actually going to turn? They were also "Rubber" because it was one of the few readily available materials. I remember the choices in the late 70's for my autocross car - solid aluminum, maybe brass or nylon, or actual bearings. Now we have far more choices and engineerable urethane. I will choose to eliminate the "slop" from Rubber bushings which delay response until they're sufficiently compressed (I.e. mechanically hardened) to respond. So, I'm a buyer

FGN59 · « **Reply #22 on:** February 05, 2020, 18:41:13 »

Well, driving skills left out of this, when I had to replace the worn bushings on the front anti roll bar on my Jaguar, I immediately felt a much improved, more precise and responsive handling, so I’m with you on all this. My concern was with the different grades of urethane (what is called durometer in this thread as I understand it), and how to chose which grade for which part of the suspension without buying a trainload of different grades for each different bushing...

pedrocamp · « **Reply #23 on:** February 05, 2020, 21:46:50 »

I've stolen knowledge from a lot of well qualified people! Even an average driver like myself would feel the difference with a package of less compliant urethane bushings installed compared to the stock rubber bushings. FGN59's experience sounds logical in that he felt the handling sharpen but may have still felt the car was still balanced... correct? Not to speak for Wallace but likely one or two grades of urethane likely enough choice for this application. It may be he finds that one material works fine in all the locations or substitutes a softer or harder grade in one or two. Given the option I'd buy a couple different durometers for some of the joints to see how it affects my car. I'd be most interested in possibly two different grades for the cone bushings at the rear trailing arm to axle location. These joints by my estimation seem to take forces from all different directions with longitudinal and lateral rotation thrown in. Not to mention the rubber ones seem to constantly squeeze out!
Russell reminds me of the distinct difference I experienced when I drove a Mercedes for the first time as a teen in the 70's, smooth ride but precise compared to the Stateside sedan competition. The Mercedes engineers had managed to find a nice balance of compliance control and vibration isolation. I was sold. That said a sportier, slightly less cushy ride can be fun on a mountain road.

doitwright · « **Reply #24 on:** February 05, 2020, 22:55:19 »

Over the past several years I have heard from a few people that Mercedes suspension rubber for our cars is not the same as it used to be tending to lean more toward the softer side. If you could produce a couple of variations like “original” and “performance” I suspect you will have a market for these parts.

russelljones48 · « **Reply #25 on:** February 05, 2020, 23:26:29 »

OK, so according to Wikipedia here's the definition of a durometer - it's analogous to the Rockwell scale for metals...

The durometer is a device for measuring the hardness of a material, typically of polymers, elastomers, and rubbers. Higher numbers on the scale indicate a greater resistance to indentation and thus harder materials. Lower numbers indicate less resistance and softer materials.

wwheeler · « **Reply #26 on:** February 10, 2020, 23:46:33 »

I dealt with rubber and urethane for 35+ years so, I can help with some of the questions. I am still trying to get more info in regards to the existing tooling before I buy it.

Hardness of rubber is measured with a spring loaded pin. How deep it goes determines the hardness. The deeper the pin goes, the softer the material. There are at least 4 ranges of hardness and is measured with a durometer. Shore has A, B, C and D scales. Shore A and D are by far the most common ranges. They overlap and there is a reason for that. At the outer ends of the scale, the measurement becomes less accurate. So the optimum accuracy is in the middle of the range. You can google it and see what I am talking about. So a 70 Shore A rubber is a very common hardness and what most O-rings are.

But, when you squeeze and bend rubber, that is NOT the hardness you feel but rather Modulus. Modulus is very commonly mistaken for hardness. "An elastic modulus is a quantity that measures an object or substance's resistance to being deformed elastically when a stress is applied to it". Not my words but that is what it is.

A good example is that urethane has a much higher modulus than would common rubber. That is the property you are after for suspension bushings. Compare a 80 Shore A urethane to 80 Shore A rubber and you will find the rubber bends much more easily. Yes the harder the material the somewhat stiffer the material feels, but modulus is more important here.

That being said, I could see using a range of 85 Shore A to 95 Shore A urethane. Any softer than 85A, you aren't really gaining much over OEM rubber. 95A is hard as a rock and most would call a plastic. Plastic BTW, is usually measured in the Shore D range. 95A is equal to 55D as a reference.

I am not however an expert in suspension systems and I could see experimenting with hardnesses. Yes, I think you could offer a mild upgrade and then the higher performance bushings. Each with its own pros and cons. That would not be an issue in production to do so.

russelljones48 · « **Reply #27 on:** February 11, 2020, 15:50:52 »

thanks for the explanation - it's helpful.. Can't wait to see what you come up with. I think modern bushings would be a GREAT addition to what's available for our

cars.. And they will not affect the car's originality if someone wants to revert to original rubber. I've got the Koni adjustables and a set of aluminum rims and I'm quite happy with the results to the handing. Can't wait to add to the tricks..

Benz Dr. · « **Reply #28 on:** February 11, 2020, 23:17:38 »

I can tell you that the Cox bushings were hard. Like hockey puck hard.

jond907 · « **Reply #29 on:** February 12, 2020, 00:19:02 »

Interested!

pedrocamp · « **Reply #30 on:** February 12, 2020, 13:02:18 »

Even more interested, thanks! Glad to see you know the materials, hope the molds work out.

wwheeler · « **Reply #31 on:** February 13, 2020, 04:53:53 »

Cox bushings were 95 Shore A. If I had to start today, I probably wouldn't go above a 90 A. 5 points do not seem like much on paper, you you can feel the difference. I would like to experiment with both 80 A and 90 A. 80 A would give you a bit of an upgrade and 90 A even more. No two people are alike and want the same thing.

wwheeler · « **Reply #32 on:** February 27, 2020, 22:01:59 »

The tools for the urethane suspension bushings are on the way!!! It looks as though I will be making these at some point soon. For the W113 Pagoda and W111 cars, the following will be available:
- front flat leaf spring
- Front sway bar (frame and end link)
- Rear axle trailing arm (frame and axle)

I have quite a bit to do and am looking at these being available in the summer or early fall. My initial plan is to make these ever so slightly softer. I think that will be a better fit for the Pagoda crowd, rather than the very hard compound used prior. But, we shall see.....

pedrocamp · « **Reply #33 on:** February 28, 2020, 21:40:22 »

Good news!

russelljones48 · « **Reply #34 on:** March 08, 2020, 19:43:16 »

I agree - great news!! Can't wait to get my set...

wwheeler · « **Reply #35 on:** June 15, 2020, 16:17:58 »

Getting closer. I have produced parts from each tool and they match the OEM in fit and dimension. The hardness is a bit softer than what Cox had. His was 93 to 95 Shore A and mine are 88 Shore A. Does not sound like much of a difference, but you can feel it being a bit softer. I think that hardness is a good compromise between performance and ride comfort. The last step in the process was to surface cut the "open pour" side flat. Sounds easier than it is, but that is now under my belt.

Shown is a rear sway bar bushing for the W112 and W109 cars with air suspension. For the W113, I have both front and rear trailing arm bushings for the rear axle, the front flat spring bushings and the front sway bar bushings.

Just a few more details to hammer out and they will be ready!

mrtzmd · « **Reply #36 on:** June 16, 2020, 06:14:17 »

Just saw this thread. Interested.

russelljones48 · « **Reply #37 on:** July 21, 2020, 22:23:59 »

Still interested. Next big project on my car will probably be all the body/engine rubber..

Rahul · « **Reply #38 on:** October 28, 2020, 07:27:25 »

I might have interest in these!

wwheeler · « **Reply #39 on:** October 28, 2020, 17:09:56 »

They are coming along and I have a test bed scheduled on a 6.3 W112. Once that is done, they will be ready for sale. I have the full tooling for the W113 cars as well as anything made in the 60s. (not W100 though). I typically sell through one of the well known Mercedes parts suppliers to help simplify on my end. I am thinking by mid-November they should be ready to go. Thank you for your patience and want to make sure I get this right the first time.

Wallace

russelljones48 · « **Reply #40 on:** October 30, 2020, 15:39:42 »

can't wait!! a winter project

rwmastel · « **Reply #41 on:** November 21, 2020, 04:05:28 »

It's been quite some time since I've been under my Pagoda. What is this front flat leaf spring you talk of? I don't remember it.

wwheeler · « **Reply #42 on:** November 21, 2020, 04:34:40 »

That is the "leaf spring" that mounts to the front of the chassis and then to the subframe. There are (4) bushings mounted there and this for the castor adjustment I believe.

BTW, getting close with production on these urethane bushings. I am taking great pains to make sure these are right the first time. I will post when they are ready to go.

tedskeff@icloud.com · « **Reply #43 on:** January 10, 2021, 03:24:17 »

Am very interested as it's time to change all of mine.

wwheeler · « **Reply #44 on:** January 10, 2021, 04:16:57 »

I have unfortunately been delayed on the start up for the bushings. 2020 has been a tough year to get loose ends tied. I am waiting on tooling that will allow me to finish the final production work. Once I get that, they are ready to go. Best date right now is mid January. So pretty close. I will post here when that happens. Thanks for your patience.

Wallace

wwheeler · « **Reply #45 on:** February 23, 2021, 17:31:09 »

It has been a year since I started this project and now we are ready to go. I am selling these through Miller's. These are not currently set up on their website, but they have committed to stock parts for the Pagodas. Attached are a couple of pics of the parts that are available at the moment. To order sway bar parts, the diameter of the bar must be known. Other than that, it is pretty standard.

PM me if you have questions.

Wallace

russelljones48 · « **Reply #46 on:** March 06, 2021, 19:36:09 »

what's the price for a set? I can't find anything on Miller's

wwheeler · « **Reply #47 on:** March 07, 2021, 02:00:53 »

PM sent.

Rahul · « **Reply #48 on:** July 29, 2021, 00:35:09 »

Curious, has anyone managed to try these out yet?

My bushings are up for replacement and I am debating whether to just stick with the OEM rubber, or try something different and longer-lasting. I am not going to have the time (or skill) to try out different setups for front/rear etc - so really looking for any recommendations on whether these are worth installing 'out the box'. If it purely comes down to experimentation or matter-of-taste I'll probably stick with OEM.

For ref, mine is a 1971 280SL, thanks.

bonbahn · « **Reply #49 on:** June 07, 2023, 14:15:40 »

This is an older thread, but it's how I found this product. I bought the urethane suspension kit for my W109.018 6.3 from Miller's https://millermbzparts.com/109-URETHANE-SUSPENSION-KIT/32-8101U .

I installed the 6 bushings on the rear torsion/sway bar. I had to cut 2 of them longitudinally with a hacksaw blade to slip them onto the sway bar. Pressing the bushing on the car for the upper holders required a long bolt and series of sockets and washers - no problem really. Pressing the bushing into the lower holder was okay, but required a ton of cleaning. It helps to deburr the metal parts and sand/file a slight chamfer on the urethane bushing's inner/outer diameter. Pressing the sway bar into the lower holder was a nightmare. I'm not a mechanic. This is supposed to be fun. It kicked my butt.

To press the sway bar onto the lower right holder, I got it started by hand then beat the hell out of it with a rubber mallet with the sway bar in a vice. The left holder has to be installed on the car, then the left end of the sway bar needs to be pressed in just the right amount for you to bolt the right side holder back in place. It is very hard to do this with the tires on. It is very hard to do this with the vehicle on jack stands because you're fighting the suspension geometry. Let all of the air out of the system, zip tie the sway bar to the upper holders, remove the rear left tire, wrap a ratchet strap around the holder and sway bar, and press until the right side holder can be bolted in place. Bolt the torsion bar upper holders, then test drive and retighten everything. You might as well plan on replacing the rear shocks because you'll need to remove them and reinstall them anyway.

The kit did not include the bushings for the 6.3's antidive bar. I probably could have bought another set of urethane front sway bar end links, but instead I bought an inexpensive rubber kit from Niemoeller that included a new bolt and sleeve. As far as I can tell, rubber might be better on the antidive because it's just up and down forces with no side-to-side movement. Tip: Mount the bolt facing up and use a jack to press it into the body so you have enough threads to start the nut under the rear seat.

The front sway bar was much easier and very straightforward. I chickened out on the rear trailing arms and front leaf spring bushings. I might do those later. The kit comes with good grease, and I used all of it just on the sway bars. No squeaks.

The ride is so much better. 4 passengers used to roll quite a bit and the car has flattened out beautifully. I don't notice much difference in stiffness/bounciness. Huge thanks to wwheeler for having the means to create this kit. Definitely worth it.

wwheeler · « **Reply #50 on:** June 07, 2023, 16:26:18 »

Thanks for the feedback! I have not done the rear sway bar on the W109, so good to hear it worked. The front sway bar benefits are well known.

Installing the bushings for the axle trailing arms for the W109 are not too bad. In fact, the rear trailing arm urethane bushing is a different design from the factory. It is a urethane Heim joint design and far superior.

If you need more bushing lubricant, you can get it many places. It is Prothane Super Grease and is Teflon based. It is imperative you use this type of lubricant for the bushings. Mineral based grease will degrade the urethane slowly over time. This is a fantastic lubricant and what I use. It is just more economical for me to buy in bulk and repackage. No secrets here.

On all models, the sway bar is a quick way to improve the handling and a great place to start.

Wallace

russelljones48 · « **Reply #51 on:** March 15, 2024, 13:03:03 »

So, Pedro and I have started (mostly Pedro) the undercarriage of the SL. This thread is pretty dormant but maybe this will revive it. Teardown and cleanup have been relatively uneventful. We're still assessing everything for the "while we're in there" decisions and obtaining parts. Seats are being rebuilt and other changes either in-process or being contemplated. I'll try and be diligent about posting the details and results. RJ

TJMart · « **Reply #52 on:** March 15, 2024, 15:49:37 »

Russell,

Good luck on the project! Looking forward to your posts.

Tony

BOTIGER1970 · « **Reply #53 on:** March 16, 2024, 00:16:10 »

Russell,
I hope all is well. Are you doing the work on the 230SL at the house? I would like to stop by and see what you are doing, if possible. My 280SL is currently getting painted. I also have a couple of questions for Pedro?
Thanks,
Mark Spencer

Cees Klumper · « **Reply #54 on:** March 16, 2024, 02:16:58 »

Is it me, or is this thread about something completely different than a specific restoration?

russelljones48 · « **Reply #55 on:** March 18, 2024, 16:51:14 »

Mark,

You're welcome to see the car, but I must let Pedro approve the invitation since it's at his house.

Cees,

I think the answer to your question is a little of both so there are 2 considerations. 1.) there seems to be a paucity of feedback on the urethane bushing set so I thought I would provide that in this thead dedicated to those parts. 2.) I'm not really interested in documentinog a suspension/drivetrain "restoration" thread but I thought some of the "while we're in there" posts might be of interest to those who were contemplating the urethane upgrade and vice versa.

I will leave the subject to the viewers. Those who wish the thread to be a bit more general but not expansive please let us know. Since those bushings are only 1 part of any ride and handling upgrade or should be - that's why I expanded..

rj

News:

Author Topic: Urethane suspension bushings - NOW READY! (Read 15117 times)

VincentR

jond907

tedskeff@icloud.com