Front lower control arm leak
 

Hi, my 2003 CLK has about 45k miles on it and a few days ago I noticed a small leak under the front lower control arm.

It was maybe 1.5 inches in diameter and looked like dark but very watery / low viscosity substance. It was not grease and a bit too watery to be oil. Wiped it clean and few days in the raw the spot appeared back. I can see it collecting at the bottom of the lower control arm (front driver side) as indicated in the picture. I did have both control arms replaced about a couple years ago.

https://mbworld.org/forums/members/d...leak-35456.gif

Question is, are these bushings or ball joints a possible leak? I understand some bushings are oil filled but I would think its more like thick grease.

I do run Bilstain PSS9 suspension and 19" wheels most of the year (except winter months) so I suppose that this can put extra strain on some of the other parts.

I do hear clicking / creaking noise when I turn the wheels all the way at the end, ball joint issue? I thought this was related to the Bilstain suspension. No real vibration or steering issues when not doing max steer.

I read this statement

So sounds like sway bar bushing might be bad (related / unrelated?).

Any idea if the liquid given its light viscosity can be from the bushings of the lower control arm or is this more likely from the sway bar bushing (if they are filled)?

Perhaps its something else dripping down and only collecting on that join? I could not find any other source.

Thank you for your help

Darius

The lower control arm/thrust arm bushings have no fluid - they are just a solid chunk of rubber. And fluid you see there is coming from elsewhere. Anti-sway bar bushings are also "dry". The only fluids in the suspension would be grease in the sealed ball joints, and oil in the shocks. A creak as you go over bumps (like speed bumps) is usually the anti-sway bar bushings. Noises when turning the wheel could be either ball joint or control arm bushings. One way to check is to jack and safely support the front end, then use a long board under the tire as a lever to articulate the suspension while listening for the noises.

Thank you for the reply, greatly appreciate it. If this is the case, I have no clue where that liquid could be coming from. I guess I will need to park her outside in day light and have a closer look. The car is too low to get under the front as it is. I do not have a floor jack and no easy way to safely lift her up to get under and take a better look. I will try to see something from the top :) I guess if I can;t see anything I will have to take her to some shop. I had a Mercedes mechanic that did things in his garage after work but he is no longer doing things on the side :(

What other parts can leak on that side of the car, front driver side rite above that area? I guess its possible that there is even rain water collecting somewhere and slowly leaking down getting dirty along the way :)

Thanks for your help

I spend more time checking the leak today and there is absolutely nothing I can see leaking above it or near by. Hear are a few pics.

https://mbworld.org/forums/members/d...stom-35477.jpg


this is from the front

https://mbworld.org/forums/members/d...stom-35475.jpg

https://mbworld.org/forums/members/d...stom-35474.jpg

this is from behind

https://mbworld.org/forums/members/d...stom-35476.jpg

These look pretty similar to W203 Control Arms, and they are silicone fluid filled: https://mbworld.org/forums/5182399-post13.html
So yeah, you need to replace them.

If thats the case (I know some BMW ones are) then that would explain the leak. I had them changed about a year or two ago so thats a very short lifespan.

Strange - it seems that the bushings are silicon filled. I replaced them on the C240 and they were completely dry - cracked and no signs of leaks, so I assumed no fluid fill.

Maybe they leaked and later the stains got washed away by driving in the rain etc ?

Could the C240 have other ones?

I checked yesterday evening after it was sitting in the garage for a whole night and day (was working from home) and there was nothing on the garage floor. Maybe it all leaked out :) It turns just fine as always, still need to get it replaced

Mine were 'knocking' when driving slowly and pressing the brake pedal. Or generally when braking for that matter. I thought it was normal but it's gone after replacing the bushes.

I believe the parts are the same between the CLK550 and C240, so maybe it had all leaked out?

I think my leak is now conatined :) or it all leaked out...

Leaking lower control arm
 

Dariusf - I refer to your thread back in 2013 re lower control arm leak and in your last post you stated that it appeared that all fluid had drained out. I have exactly the same problem (although judging from your photos not as bad) and wondered if you eventually needed to replace the control arm or whether it continued to function ok after all the fluid drained out. This is happening on a C180 W203 and given the age I don't want to spend big money on repair.

Hi, it actually was not coming from the lower control arm as I understand there is no oil in the bushing. In my case it was leaking from the valve gasket and dripping on top of the lower control arm appearing like its coming from there. I did have the valve gaskets replaced as well as motor mounds and eventually had to replace lower control arms. These do not last that long and I had to replace them again last month. I opted to replace the whole arms as the cost was not much more then the cost of the ball joints and bushings. I got these from Amazon and it cost me $80 in labor.



.

Thanks Darius for the quick reply. Now I'm confused. My problem is with the right front upper control arm bush which sits well clear of the side of the M111 engine. The top of the control arm bush encasing can be clearly seen looking down into the engine bay from above and there is nothing above that could possibly drip down and hit the bush at that spot. I am convinced the front control arm bushes are filled with some type of fluid thru reading the many other threads on this topic - it is a common problem and it appears my leak is coming from the center of the bush. Additionally, the fluid leak I have makes the same pattern on the arm at the bush and is exactly the same color as that shown in your photos. It is definitely not oil but rather a water based fluid with an earthy, organic smell.

I think I'll just keep my eye on any deterioration in handling or any new vibrations once all the fluid has escaped before I do anything in the hope it won't make any difference. I priced a new genuine MB control arm here in Coffs Harbour @ $564 plus $75 for the bush (approx $500 and $60 in your money) and that's without fitting. Unfortunately Amazon doesn't freight these parts to Australia. Although the car is 17 years old it has only done 44,000 km and otherwise drives like new so I think I'll stick with MB parts. I'll probably attempt to replace just the bush myself when I get the time.

Thanks again.

Some stated there is some silicone fluid inside, regardless if you see it leaking at some point your pushing will deteriorate and you will need to change it. You can get just the pushing and have a mechanic replace it with a press.In my case both sides were quite gone and the cost of the whole arm with ball joint and . busing on the ends at $86 for the pair was just not worth massing with. Why is your dealer quoting you separate for the arm and bushing? The bushing is already in the arm. If I was you I would never be back at that place. The price is insane for a piece of metal and rubber. What a rape. All of these parts are made in china and I bet you can find them in your area of the world for a fraction of the price. Total cost for part and labor for both sides was $86+80=$168 granted it was a mechanic that has a small shop and I also gave him a $20 tip on top of that. Still was under $200

Apparently there is no bush fitted to the genuine MB control arm through dealers. Perhaps because the same arm fits later models and the bushes may be different. Anyway, whoever imports them into Australia is making their fortune. I can either buy just a new genuine MB bush @ $75 and fit that as the ball joint doesn't seem to have any play. The benefit being that the control arm will remain original oem quality OR I can replace with aftermarket german aluminium Febi Bilstein control arm for roughly US$180 which includes the bush. The latter may be best as I guess it's only a matter of time until the other bushes/ball joints disintegrate. Also, MB modified upper front control arms by including bush covers (part # A211 333 06 97) to shield them from heat I guess, but I'm unsure whether the covers will fit aftermarket arms.

I would go with the whole set, less massing around :) Is it $180 per arm or a set.

That price is for each arm but I've decided to be a dare-devil so I've ordered a genuine OEM MB bush along with a cheap Chinese bush extractor tool I found on the Internet called: Subframe Bushing Installer/Remover Tool Set Suits W202 W211 W203 - part # 203500. It is described as professional quality and if so, a veritable bargain at approx US$50 delivered. I am going to attempt to replace the bush with the upper control/caster arm still attached by the ball joint to the steering knuckle. That way I will avoid any possible damage to the ball joint if I were to try and remove it from the knuckle and also avoid having to partly disassemble the shock assembly and hub to remove the arm completely. Now if successful, the benefit of this, besides cost, is that (1) the car will still have genuine MB control arm and bush and (2) should any of the other bushings need replacement it will be a relatively cheap exercise. On the down side if it all turns to crap - ie cannot remove bush because it is seized onto the control arm OR cheap Chinese bushing tool breaks under force etc, I will be forced to remove the control arm completely to replace the bush and the whole exercise will still cost me less than the price of one Febi Bilstein upper control arm @ US$180 (plus postage);).

How did it go?

It went well. Cheap extractor/installer tool arrived within 3 days and seemed O.K. so I went ahead and purchased the bush from local MB dealer. It took me about 2 hours to undo the bush end of the control arm, extract the old leaky bush and install the new bush. The hardest part was getting enough leverage to tighten the CA bolt the prescribed 120 degrees on top of the initial 80nm in the "ready to drive position" (with the weight on both front wheels). Ended up resting the front wheels on wooden blocks which gave me some extra room. Total cost US$100. So it ended up being a relatively cheap and easy exercise and I've got the extractor tool should any of the front or rear bushes need replacing in future.

I need this tool! Please post link :)

Plus, here's a YouTube on replacing those bushings. Uses a pricier tool...

The below link is an Australian site and the tool was sent to me from Melbourne. I see that the same tool can be sourced thru Amazon UK so possibly Amazon in the US. Not sure if it will fit the bushes on the ML320 that you have listed as it is advertised as only fitting W202 W203 and W211, but I'm pretty sure W204 and W209 have the same size bushes.

I also found the "This Changes Everything" YouTube and used it for some guidance.

Good luck.
PS - after posting I tried using the below link but it didn't work. For some reason when posting only an abbreviated version of the link appears. Try typing into Google: vidaxl subframe bushing installer remover tool set suits Mercedes Benz W202 W211 & W203.



http://www.vidaxl.com.au/subframe-bu...mover-tool-set

Thanks, I think the forum does something to f-up longer links, bit I went to vidaxl.com.au and searched for mercedes bushing tool with success.

I see same tool was available on ebay in the states for US$106 but says sold out - so they are available there.
A lot less freight to pay than ordering from Aust. site.