glkoffroad

​​​in Canada those arms are like double that and then some.

habbyguy

Those "compliance" bushings in the "upper" control arm (that's what MB calls 'em) are probably the most common source of thumps and wobbles. They're fluid filled, so it's not difficult to determine if yours has failed or not - the fluid is helpfully black as ink, so you'll see signs of it running down around the silver control arm, under the bushing.

I did a short (really!) video showing how to diagnose this problem, using my 2012 "project" GLK. Those have both been replaced, but the car is waiting for my daughter-in-law to insure it and THEN take it in for an alignment. My 2011 DD is getting new "upper" control arms as well - they're a LOT better than the ones on the 2012 but I can feel the slightest bit of slop, and can see where at least one of them is leaking the black fluid. So no use putting off replacing both of them, since the new ones will likely outlast the vehicle no matter when I install them.

Here's the video:

glkoffroad

this would have saved me sooooo much time and energy lol. not to mention throwing money at parts. I saw the black fluid 2-3 years ago but did know, assumed oily gunk from else where, u can see my inner bushing was bone dry and rusty. I never had any issues except slow sharp bumps. clunk. I typically just country drive, easy. no city

habbyguy

Same story with my sister's 2001 Subaru Outback. You'd never really notice "anything wrong" driving it, but a sharp bump would result in a nasty clank from the suspension. Fortunately (for me, anyway) those compliance bushings are at the rear of the (real) lower control arm, and come off like butter with just two bolts and a nut. Took all of five minutes apiece to swap them out, and a total outlay of around $40. The GLK "upper" control arms are quite a bit spendier, but hey, you end up with a Mercedes that drives even better when you're done!

And yeah, I'll be doing a video on the swap.

John CC

The ones I replaced are called "Torque struts". They look just like the ones in the photos in this thread. Same one as in the video, too. I didn't know about the black ink, or see any signs of it.

Funny thing, though. A few weeks ago I noticed what looked like grease from the axle CV boot along the rocker panel. Checked the boot and it was intact, so I figured it came from something external.

glkoffroad

just buy the bushing and press it in, they are $30 each. $80 delivered in Canada for 2 of them. I got the highest quality lemforder ones. IMO. the arms are expensive. local parts store was $300 each arm.

habbyguy

New Lemforder (OEM) control arms were about $240 for the pair. I did consider swapping the bushings (and have done that before on other cars) but figured that I'd rather replace the ball joints as well, so in the end it's really not all that much more money - and a lot less work - to just replace the whole arm.

glkoffroad

to my future self. lemforder part number 354 0001 or mercedes 204 333 11 14

habbyguy

FWIW - I just got done swapping the "upper" control arms, and I have one very, very important bit of advice...

If you have a 4Matic vehicle, do NOT use the Lemforder control arms. Seriously!

Look at the two control arms below - the Vaico part is the same as the Mercedes OEM design.

The difference in the "housing" around the base of the ball joint makes zero difference in the RWD variant. I did one just a couple months ago (my project 2012) and the Lemforder arms went in like butter. No worries.

But with a 4Matic, that extra "edge" that Lemforder added to their arm makes it essentially impossible to get the arm in around the CV axle boot. Worse, it's got a nice sharp edge that is dandy for slicing the boot (ask me how I know), so instead of just unbolting the old one and bolting in the new one, you have to release the lower control arm (the smaller one that runs straight out to the knuckle) so you have room to swing the hub enough to move the axle out of the way (yes, requiring removing the axle bolt with a big honkin' breaker bar with the wheels on the ground, and wrestling the axle around trying not to stress or overextend it).

Here's a closer look at the difference:


Pardon the photo quality, but you get the idea.

With all the jacking around with the axle and lower control arm, I managed to also destroy the boot on the lower control arm, so I'll be swapping those out as well (I'm sure they were fine before this morning).

And FWIW, I will be posting a video on this process that covers both 4Matic (whole video) and RWD (fast forward through the sections marked as 4Matic specific).

And if I didn't mention it before, if you have a 4Matic, don't buy the Lemforder upper control arms. ;-)

glkoffroad

thanks for the feedback good to know, I was very close to just buying the arms, instead I just did the bushings. I have almost 300,000km on my original mercedes arm and they are still tight. I used my sharp grease needle to give them a little bit of new grease.

John CC

Mine is 4matic. Getting the original arms out was extremely difficult. I popped the tie rod ends loose and was able to get it out with a lot of maneuvering, sort of like a puzzle. Getting the new Lemforder arm back in was at least as hard, but possible. No damaged boots and no removing the other control arm. I'm convinced the Lemforders are OEM.
Those are the bushings. If you're ordering the arms, be sure to tell self that the numbers are different for left and right.
The parts I ordered were Lemforder 3821501 and 3821601. The equivalent MB numbers are 2043308311 (left) and 2043308411 (right) respectively.

glkoffroad

thats incorrect. these are the numbers for the bushings not the arms. about 1/10 the cost here in Canada. bushings are same part number, both sides for the BUSHINGS

John CC

OK, I thought you were saying those were the arms. I'll edit my post, and these two posts will make no sense at all.

habbyguy

John, it might be a difference in the facelift model. The original arms in my 2011 looked like the Vaico arm (with the rounded ball joint "housing"). Maybe they went to the Lemforder arms in 2013 on? IIRC, the parts catalogs list all of them as fitting 2010-2015 models, but that doesn't necessarily mean they were all the same out of the factory.

John CC

I tossed the old ones, but I'm pretty sure they had MB part numbers on them.

John CC

Well, either I was wrong when I said "Checked the boot and it was intact" or it's pay back for bragging when I said "No damaged boots and no removing the other control arm"...

Either way, there's grease, obviously from the boot, on the new strut, as well as other places. It's obviously from the CV joint. Only on the side where I saw the grease before I started down this road. Only on this side, though, where I first saw the grease, so I'm still not convinced it's from any work I did. Still no obvious hole in the boot, but I didn't jack it up to look.

So, @habbyguy , did you replace the boot yet? Any words of wisdom? I used to do them on SAABs in about half an hour, but those axles were a cinch to take out and to pull apart...

habbyguy

Oof - sorry to hear that. I knew I was taking a chance on nicking one of those boots, and sure enough, I managed to do it. I did rotate the boot with the rip up, then hit it with brake cleaner, let it dry and then slathered on a glob of RTV (or similar). When I checked after a few days, there were a few signs that there is a little grease escaping, but (last time I looked) it wasn't horrible - just enough to make my normally clean, ceramic-coated wheels look sad. ;-)

I haven't done the boots, but just got in the last of the parts yesterday (the lower control arms). I was waiting to do it all at once, since getting the car jacked up and wheels off is a big part of the total job on these two jobs (two LCAs and one boot). I'm hoping the left axle will come out easier than it did last time, but I'm betting it will (it hasn't been that long, and it was lubed well before reassembly).

I suppose I could always take a chance and try to do the new boot with the axle still in the car, but it just sounds like an opportunity to mess up the inner joint more than anything!

I should be doing that boot by early next week - I have a buddy who needs help getting a steering rack swapped, so that could push me out "a bit"...

FWIW, I doubt I'll be doing a video on the boot - there's at least one really good one out there, and I suspect mine would be more comedic than information in comparison. ;-)

John CC

Ha Ha!
Does the inner joint just pop out of the trans? Is that the one you're saying was stuck? I found a video, but the guy didn't impress me with his experience... And, it was a different model.

That said, it looked easier than I was anticipating.

Is there an existing video you recommend?

I ordered a boot kit from FCP Euro. Should be here in a day or two.

habbyguy

I did a video on getting the front axle(s) out of the GLK, because I couldn't find a good one anywhere else. The left one can be tricky...


The video I thought covered replacing the boot well can be found here:

MB2timer

When you get this issue resolved, you will have your “Serenity Now” and it will be time for the Festivus for the rest of us!
I didn’t know the Leafs, Habs, Canucks, Jets, Senators, Flames, and Oilers fans even knew about Seinfeld. By the by, I was pulling for Oilers to see McDavid get his first cup. If anyone deserves a cup, he does.

John CC

I thought you said it was going to be funny! Thanks! I'll start soaking it so it'll be ready when the boot shows up. (FCPEuro has changed their shipping process and I don't get things nearly as quickly any more. May have to start paying more for better shipping... I think I'll have to drop them a line...)

Yeah, I saw that one. Much like the SAAB setup. The outer CV joints just slid off once they were "unlocked", though, often I could get it with one shot with a dead blow hammer.