Norwichdelta06

Hey guys.. How easy is it to change out both control arms? Any special tools? I mean was just under there doing my sway bar and noticed a lot of play with the Driver lower control arm. And I noticed there was also play with the RT UPPER control arm. ? Should I just buying all 4 bushings and have them pressed in at a local shop or should I just replace all 4 arms. On a scale of 1-10 how easy would it be.

jkowtko

If you can pick up the arms for around $100 each from one of the aftermarket supplies, then you might just want to buy the whole arm. In addition to the bushing you get a new ball joint. I know the ball joints usually last longer than the bushings, but if your ball joint wears then you have no choice but to replace the entire arm ... so maybe safer to so it up front. The exception might be with the upper arms though (read on) ...

The lower control arms unbolt with only the sway bar brackets blocking them, and those are easy to remove. So it is very easy to just replace the arm.

The upper control arm ball joints are trapped by the strut mounted to the steering knuckle, so you will have to separate the strut from the steering knuckle to get the upper control arm out. If a shop can press a new bushing in place on the upper control arms while it is still on the car, that may be an easier option. There are kits for this -- about $200 on eBay -- but if the shop has this then they will be able to change the bushing on the car.

OR ... if your front struts are going, then now is the time to replace them as well.

BlackOmega

EASY is a relative term. For who's skill level?

Difficulty wise, it's not very difficult however, there's a few special tools that you may need. Most likely a spring compressor and a ball joint separator. Other than that it's just nuts and bolts.
As for parts, unless the arms are damaged, just buy the bushings and ball joints. However, if the cost of the bushings and ball joints come close to the cost of a whole arm, just get a new arm.

jkowtko

Maybe you should also say if you have a 4matic or not ... they have a different front-end suspension.

Javvy

norwich.... you need a special tool to remove the control arms if you are going to just buy the bushings, this special tool will help save the threads on the bolt end that is on the controlarm so you can reuse them. DO NOT i say DO NOT hammer the threaded end as you will destroy the threads etc on the bolt. Just buy this tool and this tool only as any other lonaer tool will not work....just went through this an did not listen to the advise and ended up destorying the controarm for no reason and ended up throwing it in trash. I could have used this tool and saved the control arm for future resue/replaceing just the bushing....

here is a link to the specific tool...


Only buy OEM lemforder bushings.....I replaced my both lower control arms on my 2002 c230, I replaced them with the lemforders ones as these are the only ones that will really last, any other brand will just die after a year....

PM me if you have any additional questions....

It is a simple job, you do have to remove the sway bar bracket or loosen them to move the sway bar out of the way to acces the big bolt...

Lemme know how it fares out...

goodluck...

Javvy

nickgailloux

Hey Guys,

Glad to see someone is attempting this recently. I have major play in the ball joint on the lower control arm (right side).

I ordered new lemforder control arms online for $144 each. I also ordered the ball joint removal tool for $30 or so.

Questions:

- How long does it take?
- I want to confirm that this process does not require compressing the spring (ie no danger of spring popping off).
- The Mercedes doc detailing this procedure (AR33.15-P-0161P) says to tighten the bolts only when the vehicle is in the "ready to drive" condition (ie not jacked up). How is this possible without a lift? Ramps?

Thanks.

jkowtko

Lower control arms -- 1 hour for both if you have all of the tools and a good lift and know what you are doing. For first-timers, with proper wrenches, torque wrench and ramps, give yourself 2-3 hours for both.

Correct. Replacing lower control arms does require you to remove the sway bar brackets, but that's not a big deal. Otherwise you don't touch the strut assembly.

Yes, ramps. When the car is on jacks, tighten the bolts barely past hand tight. Then drop the car and drive it up on ramps. The suspension may clunk a bit because the bushings on the untorqued bolts will shift. Once the car is on ramps and the suspension loaded, loosen the nut a bit to relieve any twist on the rubber bushing, and then tighten to spec (110 ft. lbs I believe). If you have fluted bolts and are using one of the side positions, remember you must not turn the bolt or you risk ripping off the tabs that lock in the flutes!.

As an alternate to ramps you could try to jack up the suspension until it starts to lift off the ramps. I don't know if there's a really good jack position under the steering knuckle so I didn't attempt it ... I found the ramp method rather easy.

BenDaniel

110 ft. lbs. Will snap the living f&@$ out of the bolt. Ask me how I know. (I have no idea what the spec is, but it is apparently well short of 110)
This is a great tip, I just used a floor jack and a piece of soft wood to spread out the load under the lower control arm beneath a load bearing point. Now I just have to wait for the morning to see if my dealer has a bolt in stock or if I have to wait 2 days for Amazon to get one to me.

jkowtko

re: torque ... its 110 ft-lbs or 150Nm for those bolts:

Here's the w203 wiki page:

https://mbworld.org/wiki/index.php/W203

and the specific install manuals for the control arms:

https://mbworld.org/wiki/images/b/b3..._arm_R%26R.pdf
https://mbworld.org/wiki/images/7/74...rmR%26R-1-.pdf

My Haynes manual says the same.

So your bolt must have been on it's way out if it broke. Those bolts are pretty beefy ...

BenDaniel

Some sleuthing says it is a 10mm x 1.5 mm (80mm length) 10.9 rated steel bolt, zinc plated. Engineering charts say 53 ft. lbs. is the safe suggested 75% clamping rating, therefore roof bolts should fail at no less than 70.67 ft. lbs.

ez53436

just to help clear things up, i have an updated wis and it says the spec is 80 Nm (59 lbs/ft) and then rotate 120 degrees more. i will be attempting this in the near future and will be using a crowsfoot adapter for my torque wrench since it can't fit between the nut and the front axle carrier (and i don't see how any others would).

after doing some research, i found that there are two ways to make sure you're doing this as accurately as possible. one way is to turn the adapter 90 degrees from the torque wrench, and this will require no calculation and you can use it just as you would without the adapter. if you choose to keep it in line with the torque wrench and you are using an 18-19 inch torque wrench, you should use about 55 lbs/ft instead of 59 before turning the nut another 120 degrees.

wvadam

get the whole arms. The ball joints are probably not far behind and you will have to then replace the whole arms anyways.

jkowtko

59 ft/lbs + 120deg ~= 110 ft/lbs? I guess I can believe that.

EOB

Finally replaced the 132K miles/original lower control arms (cross struts) and - hurrah - the knocking, rumble noise is now gone. The old arms were in pretty bad shape. You definitely could see daylight through the bushings and the ball joint end moved easily with just a flick of a finger. Thanks to the great advice on this site and with patience, I was able to complete the job smoothly. I installed a new pair of Lemforder LCAs that initially looked like the wrong part because they were silver/aluminum colored, similar to the upper control arms, but a call to FCP Euro, where I purchased them, informed all the Lemforder LCAs for this vehicle that he had in stock were silver colored. The new arms were nearly identical to the original arms and went in without a hitch. The only difference was the color (as mentioned) and the fact that the Lemforder ball joint bolt took a 6 mm hex as opposed to a T 45 torx for original Mercedes ball joint. I used a scissors ball joint separator that did the trick after about 20 turns on the right side and only five on the left (go figure?). I also installed the fluted bolts just in case needed to support forthcoming alignment. I took the advice of Jkowtko and only tighten the nuts snugly and then drove about 30 yards onto a drive-on lift where torqueing was accomplished with the vehicle in a loaded/weighted condition.

samaritrey

Awesome I bet the car also drives better now!!

EOB

Absolutely - can't believe I waited so long to do this relatively simple procedure.

jkowtko

If you haven't done motor and tranny mounts, do them next ... another noticeable difference

EOB

Okay - have to add to the list and read up on how to. Thanks

capt_paul

the rght motor mount and trns mount are fairly easy DIY. To do the left engine mount by the book, you remove the air box, intake manifold, and the supercharger to access the top bolt. When I did mine, i found a broken check valve and some rubber hoses that also needed replacing. More in other threads.....