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Replacing Your Rear Lower Control Arm Bushings - Mercedes Benz
 
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Pelican Technical Article:

Replacing Your Rear Lower Control Arm Bushings - Mercedes Benz

Steve Vernon

Time:

5 hours5 hrs

Tab:

$55

Talent:

***

Tools:

Jack, jack stands, Socket and wrench set, adjustable wrench, Mercedes-Benz Spring Compressor, Mercedes-Benz Bearing R&R Tool, a bench or floor press

Applicable Models:

 
Mercedes-Benz W124 (1986-95)
Mercedes-Benz W126 (1981-91)
Mercedes-Benz W201 (1984-93)

Parts Required:

Bushings

Hot Tip:

Put the bushings in the freezer over night

Performance Gain:

Better handling

Complementary Modification:

New shocks

The rear lower control arm to wheel carrier bushings on your W201 will eventually fail since it sees a lot of wear and tear, sits close to the ground and gets a lot of road debris thrown at it. There is a rubber seal around the bushing that will eventually wear out and expose the bushing to the elements and this will eventually cause the bushing to fail. While the rubber bushing that connects the arm to the chassis seems to last longer, you will have the arm off so you may want to go a head and replace it anyway.

Begin by safely raising and supporting your car off the ground. Please see our Pelican Parts Technical Article on Jacking Up Your Benz for more information. Next remove the rear wheels but remember to loosen the lug nuts while the car is still on the ground as you will need the parking brake off to accomplish this job. On a side note here, lately I have been using a wheel hanger tool whenever I remove the wheels from the car. It simply screws into one of the stud holes and holds the tire in place while you remove the remaining studs, it also makes reinstalling the tire a snap, as all you do is place the tire over the tool and it slides right into place. Pelican Parts sells them and I wish I had bought one years ago. There is nothing worse than finishing up a job on your car and the struggling to get the tire back on, especially if you are working in the weather.

Remove the plastic cover on the lower control arm. Unscrew the two 10mm nuts holding the cover on and then unclip the cover from the arm. Remove the 17mm nut and bolt that hold the shock to the rear control arm. Slightly lift the arm and slide the bolt out.

Next, remove the nut holding the sway bar drop link to the control arm. Again, you will probably have to lift the arm a little to get the bolt out. Inspect the drop link bushings and replace if damaged. The drop link bushings on our project car where dried out and cracked so we went ahead and replaced them.

You are going to have to remove the spring to remove the control arm and removing the springs requires the use of a special Mercedes-Benz tool; a heavy duty internal spring compressor. I highly recommend that you use this compressor tool as the springs are under a tremendous amount of pressure and can cause serious damage to both you and the car if not compressed correctly. I have yet to be able to find a spring compressor tool at a local parts store that can properly and safely compress the springs on a Mercedes-Benz to my satisfaction. Warning: Never use air impact tools on the Mercedes style spring compressor.

To remove the spring, place the spring compressor plate as high up as possible into the springs. Place the lower plate as far down on the spring as possible. Feed the compressor strut through the access hole on the bottom of the control arm, up through the upper plate and rotate it to lock into the upper plate. Once secured, use a 19mm socket and turn the tool. It will compress the springs as it turns. On the rear control arm, you will not be able to compress the spring enough to remove it with the arm attached. This does not matter as you are going to lower the arm and can remove the spring then.

Move to where the control arm bushing attaches to the chassis and remove the nut but leave the bolt in place.

Next you will need to remove the self-locking Hex nut securing the arm to the wheel carrier. Holding the arm in place pull the bolt out, and while supporting the arm, grab the spring, swing the arm down and remove the spring. Place the compressed spring aside safely

You will now have the control arm free from the vehicle. We will be pressing the rubber bushing out of the control arm later.

To prep the wheel carrier so you can remove the bushing, you will need to remove the parking brake shoes and assembly. Warning: In high corrosion areas the brake backing plate-heat shield must be inspected before attempting brake shoe replacement or adjustment. If it is in bad shape you will need to replace them. Note: The hub must be removed to replace the backing plate, destroying the wheel bearing.

Begin by removing the brake caliper. There are two 17mm nuts holding it to the wheel carrier. Support the caliper by safely hanging it from the car. DO NOT let the caliper hang by the brake line.

Once you have the caliper out of the way, remove the small screw that holds the brake disc on with a T-30 Torx. At this point, make sure that the parking brake is off. You should now be able to pull the disc off of the hub. If there is any resistance, use a rubber mallet to tap the brake disc off. Sometimes the disc will require some heavy smacks to get it off.

If the parking brake is off, but the disc still will not move, you may need to take the tension off the inner parking brake shoes in order to remove the rear brake disc. To access the adjusting screw, you'll need to rotate the disc until one of the holes for the lug bolts is at 2 o'clock for the driver side and 10 o'clock for the passenger side. If you shine a light inside, you should be able to see the screw inside the hole. You'll need to turn the adjuster screw counter-clockwise to lessen the tension on the two brake shoes. Once the tension has been relieved, you should be able to pull the brake disc off.

With the disc off you can see the parking brake assembly. There are two parking brake shoes. They are connected on the top by a spring and sit in the tension adjuster. On the bottom they are connected by a spring and sit in the parking brake expander. You will see a small retainer spring on each pad. Before you go any further make sure you are wearing safety glasses. If you don't have safety glasses, stop working and go and get some and wear them before you attempt this. The retaining springs are sticking out at a right angle to the pad. Rotate the axle shaft flange so that you can get access to the spring through one of the holes in the flange. You need to compress the spring and rotate it 90 degrees to remove it.

They make a special tool for this, and some people use a screwdriver to try and remove them, but what I have found works best is a small 7/16" socket. Place the socket on the end of a screw handle, put it over the spring, compress the spring, rotate 90 degrees and remove. There is a small hook on the end of the spring and you are trying to get the tension of it so you can spin it and unhook it from the metal. Next, move down to the metal separator at the bottom that both shoes sit in. Take a screwdriver and unhook or pry the spring from the pad. Sometimes you will have better luck working from behind the loosened pad. With the spring unhooked, remove the other small retaining spring on the other pad. Pull the brake shoes/shoes apart at the bottom until you can remove them over the axle flange. The tensioner and springs should still be attached at the top and come off as a unit.

Remove the three Allen (Hex key) bolts holding the brake dust cover plate to the wheel carrier. With the plate free, lift it over the parking brake separator and turn it clockwise until it gives you access to the joint.

Safely place and support the arm in the press. I used the large part of the tool to remove the other bushing to support the arm in, as it was the perfect outside diameter for the arm, and a 25mm socket was the perfect size to push the bushing out with. With the bushing out, clean the inside of the arm, take your bushing out of the freezer (freezing makes the rubber more dense and hard which makes it easier to push in) apply some common dish soap to the bushing and arm and press the new bushing in. Again, I used the same tool for the base and a 27mm and 29mm socket to push the bushing in.

While you can remove and replace the rubber bushing in the arm with the Mercedes-Benz tool, if you have a press you can use it instead. If you are going to have to buy one of these tools, I would buy a press, as it can be used for a lot more projects than the single use Mercedes-Benz tool.

Once you have both new bushings installed, putting everything back together is the reverse of removal.

Here is the wheel hanger tool.
Figure 1

Here is the wheel hanger tool. I highly recommend buying one as it makes getting the tires on and off a snap.

Remove the two 10mm bolts (red arrows) and the two clips (yellow arrows) and the plastic control arm protective cover.
Figure 2

Remove the two 10mm bolts (red arrows) and the two clips (yellow arrows) and the plastic control arm protective cover.

These are the three nuts and bolts you will need to remove in order to perform this job: control arm to wheel carrier (green arrow), drop link (yellow arrow) and shock (red arrow).
Figure 3

These are the three nuts and bolts you will need to remove in order to perform this job: control arm to wheel carrier (green arrow), drop link (yellow arrow) and shock (red arrow).

Remove the bolt attaching the shock to the control arm (red arrow) and slightly lift the control arm to slide the bolt out.
Figure 4

Remove the bolt attaching the shock to the control arm (red arrow) and slightly lift the control arm to slide the bolt out.

Remove the nut from the drop link (yellow arrow), slightly raise the control arm and remove the bolt.
Figure 5

Remove the nut from the drop link (yellow arrow), slightly raise the control arm and remove the bolt.

I highly recommend you use this spring compressor tool for Mercedes-Benz.
Figure 6

I highly recommend you use this spring compressor tool for Mercedes-Benz. Use of a different tool can cause damage to both you and the vehicle. Warning: Never use air impact tools on the Mercedes style spring compressor.

Place the upper disc as high as you can get it in the springs (red arrows).
Figure 7

Place the upper disc as high as you can get it in the springs (red arrows).

Place the lower spring as low as it will go (red arrow).
Figure 8

Place the lower spring as low as it will go (red arrow).

Insert the compressor strut through the hole in the lower control arm and feed it through the plates.
Figure 9

Insert the compressor strut through the hole in the lower control arm and feed it through the plates. Rotate the strut so it locks into the tabs on the upper plate. Attach your 19mm socket and start tightening. The springs will compress while tightening.

10
Figure 10

Using two 19mm sockets remove the nut holding the control arm to chassis but do not remove the bolt yet

11
Figure 11

Do not remove the bolt yet (red arrow) as once the bolt is free you don not want the arm swinging down and dropping the spring on your head

Remove the nut and bolt connecting the control arm to the wheel carrier.
Figure 12

Remove the nut and bolt connecting the control arm to the wheel carrier. Hold the control arm in place while removing the bolt

While holding the spring and control arm, carefully swing the arm down from the wheel carrier and remove the spring.
Figure 13

While holding the spring and control arm, carefully swing the arm down from the wheel carrier and remove the spring. Then remove the bolt connecting the arm to the chassis.

Remove the two 17mm bolts holding the caliper to the carrier and safely hang the caliper (red arrow), do not hang the caliper by the brake line! Using a T-30 driver, remove the securing screw on the rotor.
Figure 14

Remove the two 17mm bolts holding the caliper to the carrier and safely hang the caliper (red arrow), do not hang the caliper by the brake line! Using a T-30 driver, remove the securing screw on the rotor.

Pull the rotor off and you will see the parking brake assembly.
Figure 15

Pull the rotor off and you will see the parking brake assembly. You will be working with the shoes and the tensioner (yellow arrow), the retaining springs (green arrows) and the expander (red arrow).

Spin the axle flange so you can get access to one of the retaining springs.
Figure 16

Spin the axle flange so you can get access to one of the retaining springs.

Use a 7/16” socket, compress the retaining spring and turn it 90 degrees.
Figure 17

Use a 7/16" socket, compress the retaining spring and turn it 90 degrees. This will release the spring from its hole (red arrow) so you can remove it.

Remove one side of the lower spring by the separator (yellow arrows).
Figure 18

Remove one side of the lower spring by the separator (yellow arrows).

With the top spring and tensioner attached, pull the shoes apart so you can get them over the axle and remove.
Figure 19

With the top spring and tensioner attached, pull the shoes apart so you can get them over the axle and remove.

Remove the three Allen (Hex key) bolts holding the brake dust shield on.
Figure 20

Remove the three Allen (Hex key) bolts holding the brake dust shield on.

Spin the dust shield until you have access to the wheel carrier bushing.
Figure 21

Spin the dust shield until you have access to the wheel carrier bushing.

Here is a picture of the old bushing, you can see where the rubber seal is gone and all kinds of debris has gotten into the inner bearing (red arrow).
Figure 22

Here is a picture of the old bushing, you can see where the rubber seal is gone and all kinds of debris has gotten into the inner bearing (red arrow).

This is the bearing puller and installer tool.
Figure 23

This is the bearing puller and installer tool. It is easy to use, and walked the old bushing out in under two minutes.

Viola! A walk in the park with the right tool.
Figure 24

Viola! A walk in the park with the right tool.

This photo illustrates the old bushing (left side) and the new bushing.
Figure 25

This photo illustrates the old bushing (left side) and the new bushing. The new busing looks frosty because it was just pulled out of a freezer. Freezing the bushing before installation causes the metal to contract and makes the installation easier.

Using the same tool, install the new bearing until it is equal and flush in the knuckle.
Figure 26

Using the same tool, install the new bearing until it is equal and flush in the knuckle.

This photo illustrates how you can use a press to push out the old rubber bushing and install the new one.
Figure 27

This photo illustrates how you can use a press to push out the old rubber bushing and install the new one. I used the bearing puller tool as a base to support the arm and a series of sockets to remove and install the new bushing

Here is the old bushing out.
Figure 28

Here is the old bushing out. Put some dish soap on the rubber and the arm before installation. Don't forget to wear your safety glasses.

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Comments and Suggestions:
Gery Comments: Beautiful writeup! Thanks!
Only thing I cant find here is the part number for the bushing!
June 5, 2015
  Followup from the Pelican Staff: I'm not the best with part numbers.

Give our parts specialists a call at 1-888-280-7799. They can figure out what part or repair kit you need.
- Nick at Pelican Parts
 
dan Comments: Hi , great article im interested in the tool in images 23 and 24 , the bearing puller / installer , whats the part number on your site ? , i need to replace those bushes and ideally in situ :- Thanks Dan
March 14, 2015
  Followup from the Pelican Staff: I don't have that info handy. Give our parts specialists a call at 1-888-280-7799. They can help you find the tool. - Nick at Pelican Parts  

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