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Pelican Technical Article:

Replacing Front Struts

Steve Vernon

Time:

3 hours3 hrs

Tab:

$350 to $800

Talent:

**

Tools:

Jack, jack stands, 21mm, 22mm Socket, 8mm, 12mm Allen key, 7mm, 16mm wrench

Applicable Models:

Mercedes-Benz W203 (2001-07)

Parts Required:

New struts, zip ties

Hot Tip:

Check your bushings

Performance Gain:

Better handling

Complementary Modification:

Install performance struts and springs

The front struts, or sometimes called front shocks, dampen the ride of your Mercedes W203 and keep it rolling smoothly down the road. When they begin to wear, ride quality and vehicle handling suffers. If you notice that your vehicle is not smooth over bumps or feels soft when cornering, this could be an indicator of worn struts. To check your struts, push down on the front corner of your vehicle, (the side you want to inspect the strut on). When you give the front corner one good push down, it should bounce up, then slightly down and stop. If it continues to bounce, the struts are worn out. You have the choice to replace your struts with a factory spec set or install a more performance oriented strut and spring. A performance set of struts can greatly increase the handling of your W203. You can also replace all four springs on your car with performance springs, giving it a slightly lower stance and stiffer handling.

You will need to jack up the car and remove the front wheels to perform this job, please see our article on safely jacking up and supporting your Mercedes.

All of the hardware (nuts and bolts) are single use only. Mercedes micro encapsulates their hardware with a binding agent and even though lots of people clean up the threads, apply some blue Loctite and reuse the bolts, Pelican recommends you purchase all new hardware.

There is a plastic mount that clips into the strut and is secured with two zip ties, this mount holds the brake line, ABS sensor and wear sensor. Cut the zip ties, unclip the mount from the strut, unclip the sensor wires from the mount and slide it up the brake line and out of the way.

There is a drop link that attaches the sway bar to the strut. You will need to remove the link from where it attaches to the strut by holding the large nut with a 16mm wrench and turning the smaller inner bolt with a 7mm and push the link out of the strut and set it aside.

Remove the single large nut and bolt from the steering knuckle to strut with a 22mm socket and a 12mm Allen to hold the bolt.

There are two 21mm bolts holding the strut to the lower part of the steering knuckle. Remove these taking care that the steering knuckle does not swing out and hit something once free of the strut.

Move to the engine compartment where the strut mounts to the tower. You will need to remove the 22mm nut securing the strut to the tower. Use a 22mm wrench to hold the nut and insert an 8mm Allen into the top of the strut bolt and turn. Do not worry; the nut just secures the strut to the tower it is NOT under pressure from the spring.

Slide the strut away from the steering knuckle and pull it down out of the vehicle.

Unless you have the special tool to safely compress the spring to change out the strut you should take the unit to a shop and have the springs swapped over. Modern struts and springs are under a tremendous amount of pressure and are very dangerous to work on without the proper tool, do not attempt to swap out the strut without the proper professional spring compressor.

With the springs installed on the new struts installation is the reverse of removal.

There is a plastic mount that clips into the strut and is secured with two zip ties (yellow arrow), this mount holds the brake line, ABS sensor and wear sensor.
Figure 1

There is a plastic mount that clips into the strut and is secured with two zip ties (yellow arrow), this mount holds the brake line, ABS sensor and wear sensor. Cut the zip ties and unclip the mount from the strut, unclip the sensor wires (red arrows) from the mount.

Slide the mount (yellow arrow) up the brake line and out of the way.
Figure 2

Slide the mount (yellow arrow) up the brake line and out of the way.

There is a drop link that attaches the sway bar (red arrow) to the strut (yellow arrow).
Figure 3

There is a drop link that attaches the sway bar (red arrow) to the strut (yellow arrow).

You will need to remove the link from where it attaches to the strut by holding the large nut (red arrow) with a 16mm wrench and turning the smaller inner bolt (yellow arrow) with a 7mm.
Figure 4

You will need to remove the link from where it attaches to the strut by holding the large nut (red arrow) with a 16mm wrench and turning the smaller inner bolt (yellow arrow) with a 7mm.

Push the link out of the strut (red arrow) and set aside (I like to reattach the hardware when possible (yellow arrow) to make finding it for reassembly easier).
Figure 5

Push the link out of the strut (red arrow) and set aside (I like to reattach the hardware when possible (yellow arrow) to make finding it for reassembly easier).

Remove the single large nut (yellow arrow) and bolt from the steering knuckle to strut with a 22mm socket and a 12mm Allen to hold the bolt.
Figure 6

Remove the single large nut (yellow arrow) and bolt from the steering knuckle to strut with a 22mm socket and a 12mm Allen to hold the bolt.

There are two 21mm bolts (yellow arrows) holding the strut to the lower part of the steering knuckle.
Figure 7

There are two 21mm bolts (yellow arrows) holding the strut to the lower part of the steering knuckle. Remove these taking care that the steering knuckle does not swing out and hit something once free of the strut.

Move to the engine compartment where the strut mounts to the tower.
Figure 8

Move to the engine compartment where the strut mounts to the tower. You will need to remove the 22mm nut securing the strut to the tower (yellow arrow). Use a 22mm wrench to hold the nut and insert an 8mm Allen into the top of the strut bolt and turn. Do not worry; the nut just secures the strut to the tower it is NOT under pressure from the spring.

Slide the strut (yellow arrow) away from the steering knuckle and pull it down out of the vehicle.
Figure 9

Slide the strut (yellow arrow) away from the steering knuckle and pull it down out of the vehicle.

Unless you have the special tool to safely compress the spring to change out the strut you should take the unit to a shop and have the springs swapped over.
Figure 10

Unless you have the special tool to safely compress the spring to change out the strut you should take the unit to a shop and have the springs swapped over. Modern struts and springs are under a tremendous amount of pressure and are very dangerous to work on without the proper tool, do not attempt to swap out the strut without the proper professional spring compressor.

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Comments and Suggestions:
Michael_N Comments: Hi, I have a Mercedes C180 2005 plateW203 and have this knocking noise when going over bumps. I have had various components replaced but the noise persists. I now suspect the strut mounts to be at fault? Can the top strut mount nuts be tightened without removing any wheel and whilst the car is on the ground?
December 8, 2016
  Followup from the Pelican Staff: If noisy, they are likely faulty. Tightening them will not help. Jack the vehicle up and check for loose suspension components. Check the sway bar end links for noise. - Nick at Pelican Parts  
Joel Comments: Do you have an article covering a 2001 C240? I need to do the struts and control arms.
November 27, 2016
  Followup from the Pelican Staff: We don't currently have that tech article. If we get a chance to perform the procedure, we will be sure to document it.


I would grab a repair manual. It will have the procedure, special tools and torque specs.


Give our parts specialists a call at 1-888-280-7799. - Nick at Pelican Parts
 
kevin Comments: hey if you are having a terribly hard time trying to get the bolt and nut off the lower end of the air strut , what should you do? We hav tried everything! Heat Torch, PB blaster, torque rachet bar, a breaker bar... etc. can you help?
October 6, 2016
  Followup from the Pelican Staff: At that point, cut it off and replace whatever is damaged during cutting. - Nick at Pelican Parts  
Bill Comments: Anyone know anything about the Shock Mounting Kit, Mercedes WO133-1630112, that is supposed to be used in installing new front struts?
October 1, 2016
  Followup from the Pelican Staff: Give The Pelican Parts parts specialists a call at 1-888-280-7799. They can figure out what part or repair kit you need.
- Nick at Pelican Parts
 
SJ Comments: What are the torque specs for the bolts on replacing the front Struts?
March 18, 2016
  Followup from the Pelican Staff:
I don’t have that info.


I would grab a repair manual. It will have the procedure, special tools and torque specs.

Give our parts specialists a call at 1-888-280-7799. - Nick at Pelican Parts
 
Joe Comments: What is the color of a leaking front strut on. A 320 e 2000. I have not seen the red light warning light come on.
February 21, 2016
  Followup from the Pelican Staff: COlor of what?A warning light? Can you describe your issue a little better? - Nick at Pelican Parts  
DraginRat Comments: Will I need to have an alignment after swapping struts?
September 16, 2015
  Followup from the Pelican Staff: I would suggest you do. - Nick at Pelican Parts  
Welshman Comments: Thanks Nick
May 22, 2015
  Followup from the Pelican Staff: No problem. - Nick at Pelican Parts  
Welshman Comments: Nick I hope you got the attached photo
May 20, 2015
  Followup from the Pelican Staff: Got it, thanks. - Nick at Pelican Parts  
Welshman Comments: Nick here is the photo per 2004 erc. strut question 19 May
May 20, 2015
  Followup from the Pelican Staff: Do the rebound stops have yellow paint marks on them? If so, you have updated stops to prevent noise and the spacing is normal. Might be normal either way, I just recall the update.- Nick at Pelican Parts  
Welshman Comments: After installing front struts on my 2004 C230 Merc. there is a gap of +/- 10 mm The top nut is screwed down to required torque.
Is this normal what do you suggest
May 19, 2015
  Followup from the Pelican Staff: Where is the gap? Can you share a photo? - Nick at Pelican Parts  
lourace Comments: is this same for 4matic c240 2005 modile
November 19, 2014
  Followup from the Pelican Staff: This article applies to:
C320 (1998-2004)
E320 (1998-2004)
S320 (1998-2005)
ML320 (1998-2003)
CLK320 (1998-2004)
SLK320 (1998-2003)
C230K (2003-2005) - Nick at Pelican Parts
 
Tommy4 Comments: This is a great guide!! Thank you so much for posting. I will be ordering a new struts and mounts for the job soon.

My questions is do you happen to know the torque specs for this job?

February 20, 2014
  Followup from the Pelican Staff: What is your vehicle info? I might have some of the specs. - Nick at Pelican Parts  

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Page last updated: Thu 4/27/2017 02:30:06 AM