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I changed the rear shocks from sport suspension specs to standard shocks this weekend. On a scale of 1 to 10 to rank the level of effort I would rate this project as a 2 in terms of difficulty. Each shock took about 30 minutes to change. Add another hour for preparation, taking photos, and clean up and the total project took about 2 hours. I posted some photos in the photo gallery at this link:

http://www.benzworld.org/gallery/showlink.asp?CatID=13551&parentID=53&subname=Rear_shock_absober_install&parentname=

Here are the basic steps.

0. Tools needed: Wheel ramps, floor jack, jack stands, Hazet #2780 shock absorber socket tool, metric sockets (10mm, 16mm, 17mm), torque wrench(es) (20, 50, 110 Newtons), 13mm, 16mm, and 22mm box end wrenches.

1. Back up the car onto a set of ramps (Rhino ramps from Autozone).

2. While weight of car is still on tires, loosen the upper shock nuts on both sides of the car. Hazet tool #2780 or equivalent is needed to hold the shock rod from spinning while removing the nut. Use 13mm wrench to hold inner shaft and 22mm wrench to turn outer socket. If this is the first time shocks are being removed, you will have to cut the trunk liner to gain access to the top shock nut. You area to cut will be obvious. Some early cars had the shocks changed at the VPC so the trunk liners were already cut (like my car). Do not cut out the complete circle. Leave a small section to act as a "hinge".

3. Lift rear wheels off of ramps using a floor jack positioned beneath the differential.

4. Remove the ramps from below the wheels and place suitable jack stands below the jacking points near the rear end of the side skirts.

5. Remove rear wheels (17mm socket).

6. Remove protective plastic cover concealing lower shock bolt. This cover is held in place with two small screws (10mm hex head) as well as four plastic tabs that snap over spring control arm. The plastic tabs were not fully engaged on my car. If the holes are already cut in your trunk liner (indicating that the shocks were changed), you may want to check that these tabs are properly snapped into place.

7. Remove the lower shock bolt. Bolt and nut are both 16mm. The nut is a self-locking type with an elongated hole near the outer threads. New nuts are about $1 each.

8. Remove the upper nut if you did not already do so in step 2 above. Be careful not to drop the nut, washer, or grommet behind the trunk liner.

9. Grasp the upper part of the shock and compress it far enough to tip the top of the shock towards the outside of the car. Work the lower end of the shock free from the spring control arm. Once the shock is free, tip the top end forward to easily remove the shock absorber.

10. Remove the grommet from the shock absorber to use with new shock. My car only had 7500 miles on it. Replace the grommet if it is worn.

11. Install the new shock absorber. Insert the bolt on the lower end of the shock, compress the shock and pop the top end into place.

12. Tighten the lower bolt and nut to 50 Newtons with a torque wrench.

13. Re-install cover over spring control arm. Confirm that four plastic tabs are properly engaged.

14. Repeat steps 3 through 13 on the opposite side.

15. Install rear wheels and torque lug bolts to spec (110 Newtons or 81 foot pounds).

16. Lower car to ground.

17. Torque upper shock nuts to 20 Newtons using Hazet shock absorber tool. This tool is intended to be used with a Hazet torque wrench. I imporvised by using a 7/8" crow foot with my torque wrench.

18. Take a few minutes to admire your work.

The Hazet #2780 tool was very useful. Price from the MB dealer was $55. If time permits, I may make an equivalent tool and post a "how to" thread on the forum.
 

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This is very useful. I have a few questions:

1. Does a standards set of strut tool work such as Lisle Universal Strut Remover instead of the Hazet?
2. Why are you changing to a "standard" shocks?
3. Did you consider a Bilstein shock?
 

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Good question: why did you change the shock absorbers to standard?
I assume you have Sport Suspension. Are you sure standard shock absorbers are OK on a Sport Suspension?
Thanks for the instructions and pics.
 

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Discussion Starter #4
1. I am not familiar with the Lisle tools. You do not need a spring compressor to remove the rear shock absorbers. The nut on the top side of the shock is 17mm hex. The flat spot on the end of the shock rod is 5mm thick. You need a tool to keep the rod from spinning while removing or installing the nut.

2. I wanted a more comfortable ride and extra ground clearance in the front. This thread is just for the rear. I will post a separate "how to" thread for the front struts next month.

3. Yes, I considered Bilstein shocks. But I assumed they would be stiffer than the standard shocks. I did not have the budget to get the fully adjustable Carlsson RS suspension or the Bilstein PSS9 kit. I also was concerned that the range of the adustable shocks would not start with the same ride as the standard shocks.

CalifSLK - 1/2/2006 1:45 AM

This is very useful. I have a few questions:

1. Does a standards set of strut tool work such as Lisle Universal Strut Remover instead of the Hazet?
2. Why are you changing to a "standard" shocks?
3. Did you consider a Bilstein shock?
 

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Discussion Starter #5
The difference between the Sport Suspension and the Standard Suspension is the front struts, front springs, and rear shocks. Changing these three pairs of parts converts from Sport to Standard suspension. So, yes by definition the standard shocks will work. The rear springs are the same for sport or standard suspension. The front springs are a little tricky since there are different part numbers for both the sport and standard series of springs. The springs are specified based upon the options in the car (MT vs AT, Xenon headlights, etc). Each option is assigned "points" and the springs are determined by the number of total points.

EricMB - 1/2/2006 3:42 AM

Good question: why did you change the shock absorbers to standard?
I assume you have Sport Suspension. Are you sure standard shock absorbers are OK on a Sport Suspension?
Thanks for the instructions and pics.
 

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fgwinn - 1/1/2006 11:38 PM

I changed the rear shocks from sport suspension specs to standard shocks this weekend...
Great "how to" document. Thanks for posting!!
 

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fgwinn - 1/2/2006 4:03 AM
The rear springs are the same for sport or standard suspension.
I guess that explains why so many complain that the rear has too much wheel gap with or without the sport suspension.
 

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fgwinn - 1/2/2006 3:57 AM

1. I am not familiar with the Lisle tools. You do not need a spring compressor to remove the rear shock absorbers. The nut on the top side of the shock is 17mm hex. The flat spot on the end of the shock rod is 5mm thick. You need a tool to keep the rod from spinning while removing or installing the nut.

2. I wanted a more comfortable ride and extra ground clearance in the front. This thread is just for the rear. I will post a separate "how to" thread for the front struts next month.

3. Yes, I considered Bilstein shocks. But I assumed they would be stiffer than the standard shocks. I did not have the budget to get the fully adjustable Carlsson RS suspension or the Bilstein PSS9 kit. I also was concerned that the range of the adustable shocks would not start with the same ride as the standard shocks.

CalifSLK - 1/2/2006 1:45 AM

This is very useful. I have a few questions:

1. Does a standards set of strut tool work such as Lisle Universal Strut Remover instead of the Hazet?
2. Why are you changing to a "standard" shocks?
3. Did you consider a Bilstein shock?
Thank you for the good info.

Because the Bilsteins are single tube design with a floating piston, they will appear stiff at rest. Once underway they are not that bad. So far I had them on a VW, Suburban and Volvo. They improved the VW cornering without a roll bar. They kept the 12 years old Suburban as tight as when it was new. Many versions are hung upside down with the shock body attached to the car and the rod side attached to the suspension. This is suppose to reduce unsprung weight. Frankly I haven't had a car that would benefit from this until may be this R171.

The Lisle Kit 63400 only has 7mm and 10mm flat spot tools so it doesn't work. It does work for the Bilstein shocks.
 

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Very interesting! Thank you for that info reg the difference between the Sport and Standard Suspensions.
Now, another important question( if the answer is yes, I might go for changing my rear absorbers to standard!)
After changing the absorbers, did you notice a significant difference? Do you find the ride smoother now? Do you think it was worth the time and money?
I drive in San Francisco a lot, where I have to deal with lots of bumps all the time! [:(]
 

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Discussion Starter #10
Keep in mind that I am only half way thru the suspension conversion. I still have to change the front struts. I have only driven the car about 10 miles since exchanging the rear shocks. And this has been over relatively smooth roads. I will provide an update after I swap out the front struts and springs. My gut feeling is that you won't feel a significant difference if you only change the rear shocks.

You do have my curiousity peaked so I may try one stretch of road that was always very choppy before I change the front struts.

EricMB - 1/3/2006 2:21 AM

Very interesting! Thank you for that info reg the difference between the Sport and Standard Suspensions.
Now, another important question( if the answer is yes, I might go for changing my rear absorbers to standard!)
After changing the absorbers, did you notice a significant difference? Do you find the ride smoother now? Do you think it was worth the time and money?
I drive in San Francisco a lot, where I have to deal with lots of bumps all the time! [:(]
 

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After I remove the front struts I hope to sell the front and rear parts as a set. However, I plan to keep the springs. It will take some effort to figure out which front springs you need. My approach was to find someone with an SLK with all of the same options except for the AMG body kit. Then using the VIN from that car ask the dealer parts department for the corresponding front spring number.

slktyperice - 1/4/2006 2:20 PM

Would you consider selling your sport shocks?
 

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Yeah I'm looking to buy as a set. I'm going to get the H&R springs so I won't need matching springs. Any ETA on the install?

fgwinn - 1/4/2006 7:30 PM

After I remove the front struts I hope to sell the front and rear parts as a set. However, I plan to keep the springs. It will take some effort to figure out which front springs you need. My approach was to find someone with an SLK with all of the same options except for the AMG body kit. Then using the VIN from that car ask the dealer parts department for the corresponding front spring number.

slktyperice - 1/4/2006 2:20 PM

Would you consider selling your sport shocks?
 

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Discussion Starter #15
Homemade strut socket tool for rear shocks

Strickly speaking I did not need to make a tool for the installing the rear shocks since I already purchased the Hazet #2780 tool.
However, I wanted a tool that would let me torque the nut on the top of the shock to 20 Newton meters without using a crow foot.

I had already modified a 13/16" spark plug socket to use with the front struts which requires a 21mm socket (13/16" = 21mm). The rear shocks use a 17mm nut. I made a 17mm "insert" for the spark plug socket from a 17mm long reach socket. It took about an hour to make this insert by filing the socket into a hex shape with a good mill file. I used micrometers to measure the wall thickness as I filed the insert to shape. The first photo shows a standard 17mm socket and the partially completed insert. The second photo shows the insert cut to length.

I made the inner "socket" to hold the 5mm flat spot on the shock rod from a 10mm Allen wrench. Allen wrenches are pretty tough so this took another hour to fabricate. I drilled two 4mm holes into the end of the 10mm hex wrench. I then used a 5mm drill and a diamond Dremel tool bit to trim the slot in the end of the Allen wrench to fit the flat spot. After cutting the Allen wrench to a 1 1/8" length I drilled a hole in the opposite end and tapped a 5mm thread. I used an oversized drill since I did not want to break the tap cutting the thread in Allen wrench stock.

The third photo shows the 17mm insert in the spark plug socket and the 10mm Allen wrench stub slipped into a box end rachet wrench. I added a threaded coupler with a screw in the end of the assembly to hold the flat washer in place so that the Allen wrench stub does not accidently fall behind the trunk liner.

The final picture shows the tool assembled.
 

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