Floobydust

Last year, I installed H & R lowering springs on my '95 cabrio with new springs pads (3 bump front / 2 bump rear) and things have been fine since I installed them. Then, about two months, the car started to develop a clattering/clacking noise in the left rear when I went over sharp bumps. The noise was only happening on the down stroke (e.g., when the suspension is unloading). I was convinced the problem was a bad bushing, but after I replaced the rear links, the lower control arm bushings, and the diff carrier bushings, the noise remained (and got worse).

While I had the car up on the lift again to again search for the noise, I accidentally bumped the spring and noticed that it was loose! I removed the spring and put some heat shrink tubing on the bottom coil and, voila, the spring was tight and the noise was gone. Without the heat shrink, the noise comes back, telling me there is something wrong with the spring. It seems like the spring is not properly fitting into the tapered perch stamped into the lower control arm.

I have a lessor noise in the left front, which again, I thought was bushings/ball joints, but now think it also might be the springs.

Has anyone had issues with noises/spring clatter with H & R springs? Have there been fit or settling issues?

Thanks,

- FD

Saijin_Naib

No issues yet, but they've only been on a few days. This is slightly alarming however.

WDB124066

Do you have Sportline or standard shocks? Could it be the standard shocks are not handling the rebound damping on the shorter stiffer springs, allowing too much extension, ie the springs are "punching out" the shocks. Maybe you need to go to a Bilstien aftermarket "performance" shock to suit the springs, or a standard Sportline shock.

I have no experience with this set up, just asking the obvious questions......

RBYCC

No problem in four years with H&R lowering springs and Bilstein HD's on a C124

Floobydust

Thanks everyone - I should have mentioned in my post that I installed new Bilstein HD's all around at the time I did the springs.

The more I look at it, the more it looks like the bottom coil of the spring is not correctly following the taper of the debossed perch area on the lower control arm. This seems to allow a portion of the coil to leave contact with it on suspension rebound which results in the clatter as the suspensions settles. The other thing I noticed is that the Cabrio springs (H & R No.: 29894) are unique to the Cabrio and shared by no other W124 application. I wonder if their unique design has less operational latitude than some of the other W124 applications?

Ed - Do you know how many "bumps" you are using on your spring pads?

Thanks!

ptoro01

Up on a lift, the weight of the assembly with shorter spring might leave the spring completely relaxed. The bilstein HD's being longer than sports would allow for this to happen.

What i'm getting to is, check the lower shock bolt. When I installed my setup, the nut stripped the bolt and it wasn't squeezing the control arm shut. The rattle might be from the shock and bolt interaction.

And up front, might be brake pad rattle.

Apart from that, I wouldn't think its possible to install the spring upside down and if your old spring had a busted half coil, you would have noticed it. So my brainstorm ends with are they the correct springs and original control arms?

RBYCC

Whatever came from the factory.....had no reason to change the original ones.

Are your springs seated correctly in the spring pad?

If you look at the spring pad it has a bit of a "screw" molded into it and the flat top spring must "wind" into it...

teezer

i'd check the front & rear shock mounting bolts/nuts ~~~ the rubber bushings will reseat sometimes with miles

Floobydust

Well, I took the rear springs out today because I was planning to "dip" the bottom coil of the springs in polyurethane to buffer the metal-to-metal contact area as a potentially permanent solution to the spring clatter. The thought was that the H&R design doesn't provide quite enough pre-load on a cabrio. The material is McMaster-Carr, Shore 80A hardness catalyzed polyurethane that is often used to cast DIY custom polyurethane bushings for automotive suspensions (the 60 D is also used) and was intended to provide a permanent replacement for the heat-shrink from before.

But when I got them out, I found that the left spring was about ~12 mm shorter that the right spring! I took the attached picture and sent it to H&R who said that such a failure is extremely rare (as in, "I haven't seen that in the 15 years I've been here"). Hmmm, how did I get so lucky?

To be truthful, I'm suspect of the whole spring set. I have another noise (much less prominent) in the left front that I think is also a spring problem. I really like the lowering and the firmer ride (which is really not much more so than my ML), but the quality and/or engineering in these springs just doesn't seem to be there.

It's interesting, H&R makes a big deal out of their ISO9000X and TUV certifications, but since I deal with those standards and notified bodies on a daily basis, I can tell you that one could get a steam powered left-handed sewer flute CE marked and TUV recognized if you have the right paperwork, but that doesn't mean you really want one.

Anyway, it will be two weeks to get a replacement spring (because of Turkey day - how appropriate). In the mean time, I'm going to pull the fronts and check them too.

Sportlines are looking better and better . . . Mercedes' may have their quirks, but their engineering is as solid as the pavement on the autobahn.

Thanks again everyone for your help and suggestions,

- FD

stormtigers

Well if that don't beat all !
Never seen it and hope I never do.

How in hell do manufacturer's expect you to trust them when crap like that goes through unchecked ?

I am left shaking my head in disgust on your behalf Flooby old son..

I hope you give them a right royal reaming of the brown chocolate speedway !
(aka chew their *** out !)

Floobydust

I learned a few things over the holiday break. I took the fronts springs off to check them because I was getting a noise in the left front. When the air temperature was warm, I would get a clicking at random times. Sometimes you could make it happen just by kicking the tire.

Well, I found the the left front spring had a sharp burr on the end from the wire cutting process (sorry about the blurry pic) that dug into the de-bossed spring perch on the lower control arm (the bright spot in the pic). This created a two position "detent" that allowed the spring to click through, kind of like a toggle switch.

I was going to clean up the burrs and re-use the control arm, but I noticed the ball joint bellows had come off. Upon close inspection, I noticed that the nylon insert the limits travel was shattered! I'm not sure why this failed so soon or if I damaged it during installation (over flexing the joints might do it). Of course, I thought it might have something to do with the lowering or the monoblocks a.k.a., cinderblocks and their substantially larger un-sprung weight. Either way, the control arm is toast, so I will be replacing, not re-conditioning.

As time goes on, I'm getting less and less enamored with engineering / Q.C. behind the H & R springs

- FD

WDB124066

Well if you do get new LCA's will you still go with FB ones or get the proper Genuine MB article. I just had my FB ones swapped out after 5,000 k's on them. I was a bit p1ssed that they got the bushes assembled incorrectly and thought it better to replace than rebush.

The spring markings (factory Sportline) on my car are,

Rear; One yellow dot, three silver dots, then next coil down one blue dot (long option)
Front; One yellow dot, two silver dots, then next coil down one blue dot (long option)

Hope this helps......

Floobydust

WDB124066 -

Thank you very much for the spring color codes!! They should be very helpful.

I did go with FB LCAs because of availability. My only other choice at the moment would have been the Chinese knockoff, and I didn't want to go there (although their Q.C. would probably be better than FB these days!). I hope the FBs come with the bushings in the correct positions this time. If not, I'm going to send a letter with photos to TUV who is FBs notified body. As an ISO/CE manufacturer, FB will have to generate a response and take some action. In the past, it seemed to be a problem affecting only the right side LCAs, so my odds might be better.

Thanks again!

- FD

Floobydust

Cost of new Cabriolet H & R Springs: $252.82

Cost to diagnose and repair problems caused by new Cabriolet H & R Springs: $1,282.41 + countless hours under the car

Great advice and support from forum members: Priceless !

WDB124066

Don't put too much faith in ISO 9000 or TUV for that matter, most people just ignore it.

If you can go with the genuine article you should have a far higher degree of confidance it will be right, how do you know they are using the correct durometer rubber, or the proper compond, or correct dust covers etc etc. As you mention above, often the more expensive part is cheaper. The LCA's are a critical piece of kit and affect the car in so many ways, save up and by the MB parts would be my leaning here, it just might be worth it in the long run especially with stiffer springs and heavier wheels.

Floobydust

Well, the new LCA and spring came today and I thought I was all set to resolve all the reaming issues before real winter sets in. But things didn't quite work out. . .

First the new Febi LCA has the wrong bushing in the front position!! As you can see from the photo it has the front bushing from the W201 (one large bump) instead of the 2 - 1 bump for the W124, W129, & W140 LCA's. Yet the part number is the correct one for W124 (MB: 124 330 34 07 / febi: 15694). It seems like Febi's quality has gone to hell in a hand basket these days. The part was even made in Germany. Unbelievable. I have a set of Genuine OEM bushings which I could use to replace these, but I'm so ticked off at Febi, I may just send it back.

Second, the new spring length is halfway between the old right spring and the failed left spring. What's up with that? Really not happy the H & R these days either.

Lastly, I had to chance to look at the new ball joint and determined that the shattered nylon in the old ball joint is not a bump stop as I thought. Instead, it is an integral, load bearing part of the joint. The good news is that this means I did not do the damage at installation, but the bad news is, this means the joint was torn apart by road forces. The combination of stiffer springs, shocks, and heavy monoblocks was simply too much for it. This really does not bode well for long term durability.

The warm weather we have been having has been a boon, but it's gett'n to be time to put this away for a while. I hope I can get these resolved before winter comes or my patience ends.

- FD

WDB124066

Weigh the car and put the longest spring in the heaviest corner....???

I can honestly say I'm over non Genuine parts. I went down that route a year or two ago, changed my mind and replaced everything non genuine that I put on, (except the wiring loom), with the real mckoy. Apart from the loom there is nothing on either of my cars that didn't come through the Dealership or off another 124 with the star on it. Cost a bit more, but I think if you want the car to be at its best that is really the only way to go.

I get a decent discount and very good service with advice, so all in all I reckon it just might work out as cheap as knockoff (OEM BS) parts by the time the messaound factor is factored in - or, if it cost a bit more it aint much more and it has the added bonus of not having to worry if that noise, vibration or overheating etc is caused by a faulty part.

If I want something cheaper I'll be buying something Japanese.

Floobydust

Just as a follow up, H&R finally tested the rear spring I sent back. This is the spring that became so short it would uncouple from the spring perch on bumps and clatter. They wouldn't tell what they found, but they replaced it (issued a credit, really) under the warranty. Hmmmmm.