Pelican Parts
Mercedes-Benz Parts Catalog Accessories Catalog Mercedes-Benz How To Articles Mercedes-Benz Tech Forums
Call Pelican Parts at 888-280-7799
View Recent Cars  |Shopping Cart Cart | Project List | Order Status | Help
Bookmark and Share

Pelican Technical Article:

Front Shock Absorber Removal

Kerry Jonsson

Time:

4 hours4 hrs

Tab:

$500

Talent:

***

Tools:

19mm, 22mm wrench and socket with ratchet and extension

Applicable Models:

Mercedes-Benz R129 (1990-02)

Parts Required:

Front shock absorbers

Hot Tip:

Use sockets with breaker bars because the fasteners are tight.

Performance Gain:

Eliminate excessive front end bounce from worn shock absorbers

Complementary Modification:

Change sway bar bushing at the same time

The total weight of a car is supported by the springs at each suspension corner of the vehicle. As you drive your car the wheels hit bumps and the spring absorbs the shock of the bump. The coil spring does not want to stay compressed. It wants to expand back to its normal height as fast as it can. This would of course slam the wheel back into the ground creating another impact with the road. Since you are still driving, you will also hit additional bumps so the process repeats itself. While you are driving this would feel like the front end is bouncing up and down. At high speeds this can lead to a loss of traction and poor road feel. The shock absorber does help a little while the spring is being compressed but the main purpose is to slowly bring the spring back to its normal height so it does not slam back into the road surface. This is known as rebound dampening. When a shock "blows" internally it does not have any rebound dampening so the front end bounces up and down. In this tech article we will show you all the steps to replace your front shock absorbers.

These fasteners are going to be tight and there may not be a lot of room to swing the wrench. You are going to have to be patient and use some force to remove fasteners and components to rebuild your front end. Corrosion may hold a component in even after you have loosened a fastener.

Lift and support the front axle of the vehicle. You have to remove the tires to perform this job and it does make access much easier since you may not have access to an automotive lift. See our tech article on jacking up and supporting your vehicle and then remove the front tires.

The procedure to replace the front shock absorbers is the same for both the left and right sides. These pictures are of the left side of the vehicle. It is recommended you replace both sides at the same time to keep your handling neutral.

Remember your car may have been serviced before and parts replaced with different size fasteners used in the replacement. The sizes of the nuts and bolts we give may be different from what you have so be prepared with different size sockets and wrenches. This is what we had on our car. Someone replaced the Allen head fasteners with 13mm fasteners which were harder to remove.

This Picture illustrates the left side wheel well.
Figure 1

This picture illustrates the left side wheel well. Remove the 19mm strut fastener (green arrow). You will have to counter-hold the back of the bolt with a 19mm wrench, pictured here.

Pull the washer and bolt out of both the shock absorber and spindle mount.
Figure 2

Pull the washer and bolt out of both the shock absorber and spindle mount. The ABS sensor connector is also held on with this fastener. It can hang loose while you remove the shock absorber..

Put a jack underneath the lower control arm to support the arm and spindle while disconnecting fasteners.
Figure 3

Put a jack underneath the lower control arm to support the arm and spindle while disconnecting fasteners. Working at the base of the shock absorber, remove the two 19mm fasteners (green and yellow arrows) that hold the base of the shock absorber onto the spindle. One of the fasteners you cannot see (green arrow) because it is hidden behind the shock absorber in this picture.

With the base of the shock absorber loose, rotate it clockwise until you see the electrical connectors clipped on to the shock absorber body.
Figure 4

With the base of the shock absorber loose, rotate it clockwise until you see the electrical connectors clipped on to the shock absorber body. Push in on the locking tab (red arrow) and move the electrical connector mount in the direction of the blue arrow to remove it from the shock absorber. Grab the smaller harness (green arrow) and pull it away from its holder in the direction of the yellow arrow.

This Picture illustrates the engine compartment at the top of the left side shock tower.
Figure 5

This picture illustrates the engine compartment at the top of the left side shock tower. Remove the 22mm fastener (green arrow) at the top of the shock absorber. If the shock absorber shaft spins with the fastener, insert a 5mm Allen head socket in the top of the shock shaft (yellow arrow) and counter-hold it with a ratchet.

Twist the shock absorber retaining bracket 45 degrees and wiggle it a little to get it off the shock absorber mount.
Figure 6

Twist the shock absorber retaining bracket 45 degrees and wiggle it a little to get it off the shock absorber mount.

Pull the shock absorber away from the spindle and pull in downward to remove it from the vehicle.
Figure 7

Pull the shock absorber away from the spindle and pull in downward to remove it from the vehicle.

Make sure you install the new or used bump stop (green arrow) on the new shock absorber before installation.
Figure 8

Make sure you install the new or used bump stop (green arrow) on the new shock absorber before installation.

If you are replacing the shock absorber upper mount remove the three 13mm fasteners (green arrows) at the top of the shock tower.
Figure 9

If you are replacing the shock absorber upper mount remove the three 13mm fasteners (green arrows) at the top of the shock tower. We suggest replacing this part as it wears with the strut.

Pull down on the upper shock mount and remove it from the vehicle.
Figure 10

Pull down on the upper shock mount and remove it from the vehicle. Installation is the reverse of the removal procedures. Install the upper shock mount in the shock tower and tighten the fasteners. Then install the shock absorber shaft in the upper strut tower and install the upper shock mount retaining bracket. Tighten the fastener and install the two electrical harnesses to the side of the shock absorber body. Line up the two bolt holes at the base of the shock absorber using the jack if you need to and tighten those fasteners. Fit the ABS sensor connector bracket in place and install the washer and fastener then tighten it. Install the wheel and drop the car and youÂ're done.

Bookmark and Share
Comments and Suggestions:
Kenny Comments: Currently driving a 1993 500SL. Purchased a pair of new front bilstien b4 shocks...roads where im from are not exactly german standard. Since the car is already so low originally i cannot get through any journey without the car hitting the bump stop at least a few times. I can get by driving slower but its very annoying considering i never get this problem with my other cars with much less performance. What are my options for improving the suspension?
March 14, 2017
  Followup from the Pelican Staff: The springs are likely work out. I would have ride height measured, if low, replace the springs. - Nick at Pelican Parts  
Hannu Comments: Hi, I have a -95 sl 600 , it has hydraulic suspension that is not working, it had a leak in the area where all the hydraulic lines come together in the distributor, leveling device control valve and height control valve, I replaced the height control valve and 7 small o rings 6 of them between the two components where I thought the leak was one o ring was on some kind of rod with long bolt, I don't know the purpose of this part after putting it all back together the leak was significantly reduced, now only one drop per minute, but the front suspension was now completely collapsed, I ran the engine for few minutes but nothing happened exept white fume started to come out from tail pipe and the yellow oil can light came on, it was white odorless fume. I am kind of lost with my project, my question : how do I get the fluids to fill up the system ? is there some type of reset and , or bleeding that I need to do ? When I examined the self leveling device control valve part # 1293200858 I notised that there is two potential accesses inside of it, can it be rebuilt ? If I fail in everything on the hydraulic suspension situation , can I replace the system with regular shock absorbers from 90-95 sl 500 this would save me lots of money and headaches in the future and now. Second part of the question is about the white fog, the engine has 70.000 ml. Before I started fixing things the car run beautifully, and the oil pressure gage showed max. Pressure , the check engine light has been on since I bought the car. Thank you in advance of any possible help before you answer any of these questions let me know the financial element of this consultation service. Mahalo thank you in Hawaiian. One more thing if you sell a good shp manual for this car I would like to buy one, if it is software I have apple I pad.
March 21, 2015
  Followup from the Pelican Staff: Were the O-rings Mercedes-Benz parts? Or did you find a comparable part? That could be the issue. I would check the area you installed the new sealing O-rings for pitting if they were OE parts.

I am unsure about rebuilding. You can try calling a few suspension rebuilders, there are companies that rebuild the struts, they may be able to help you.




White smoke is likely coolant. I would pressure test the cooling system. If the system will not hold pressure and there are no external leaks the head gasket may be faulty. - Nick at Pelican Parts
 

QUICK LINKS
About Us
Careers
Pelican Parts, Inc.
1600 240th Street
Harbor City, CA 90710
Order Online or Call:
888-280-7799
CONNECT WITH US
NEWSLETTER
Sign Up for Pelican Pit Stop News & Special Offers
Page last updated: Mon 5/22/2017 02:32:21 AM