Rear axle

Back to: WIS 32.00 General

Identification - Rear Drive/Axle Suspension

Components - Rear Drive/Axle Suspension

Lower Bushing - Rear Drive/Axle Suspension

The Lower Rear Axle Suspension Bushing, item (17) and item (10) below, is located at the strut supporting joint in the wheel carrier.

Designations - Rear Axle Suspension

Part	Part no.	Image	Description
17	A2203520027		Supporting joint. Damper strut mounting. Non-OEM part by TRW - JBU167.
25	N910105014017		Hexagon head bolt. Hydropneumatic spring leg to spring control arm M14X1.5X80.
30	N000000003277		Nut. Hydropneumatic spring leg to spring control arm M14X1.5.

Part	Part no.	Image	Description
10	A2203520027		Supporting joint (left and right). Non-OEM part by TRW - JBU167.
42	A2209900604		Bolt. Spring control arm to wheel bearing (left and right) M14X1.5X80.
45	A1403521576		Washer. Spring control arm to wheel bearing (left and right).
50	N000000003281		Hexagon nut. Spring control arm to wheel bearing (left and right) M14X1,5.

Identifying the components in this diagram with same nomenclature as above.

• Item 95 Camber Srut (2)
• Item 120 Torque Strut (3) (Radius Rod)
• Item 160 Track Rod (4), Tie Rod Joint (4c)
• Item 185 Thrust Arm (5)

Issues - Rear Drive/Axle Suspension

• Squeaking, creaking noises from the rear axle suspension is a common problem.
• The axlel ball joints that look like bushings lose their internal lubrication.

There is a ball joint at the bottom of each suspension AIRmatic strut and another one at the back of the wheel spider. Four ball joints in total. There is no part number for the bottom strut ball joints but they are the same as the outer ones.

It is recommend to replace both the strut ball joints and the outer ball joints when during replacement.

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W220 squeaking noise from rear suspension.

• Unevenly worn tyres that can not be corrected by wheel alignment.

Uneven Rear Tyre Wear due to Worn Torque Strut (3)

Parts - Rear Suspension

• M-B: A2203520027.
• TRW: JBU167.

Tools - Rear Suspension

• To remove and replace the bushing a special tool is needed.
• Removal and Installation Tool W202589004300 (see Special Tools page).

DIY Tasks - Rear Suspension

Assessing Wear - Rear Suspension

Use a large shifting spanner (handle 300mm long) to tightly grip each Rear Axle Component in turn. Measure the movement at the end of the spanner handle as force is applied. The results will give an indication of the amount of wear occurring in each axle component.

Typical results for a W220 with 240,000Km;

Indication of Wear Rear Axle Components

Rear Axle Component	Rear Left (RL) Measurements [mm]	Rear Right (RR) Measurements [mm]
Camber Strut (2)	15	10 -15
Torque Strut (3)	20	30
Track Rod (4)	15 - 20	10
Thrust Arm (5)	1 -2	1 -2
Tie Rod (25)	0	0

The conclusion with these results was that the Torque Struts need replacing. Consequently it was decided to replace all possible wear components while the rear end was dismantled. See below for DIY.

Replacing All Worn Components - Rear Suspension

After assessing that the Torque Strut (3) was badly worn and the most likely cause of uneven wear on the inner edge of the rear tyres, the decision was made to replace all components that could wear after 240,000Km life.

All the components in the table above were replaced.

WARNING: Replacing the Torque Strut (3) requires lowering of the complete Rear Suspension Sub-Frame by about 200mm as it is impossible to withdraw the Torque Strut (3) inner bolt without doing so. Consequently before starting make sure to either purchase or manufacture 4 off long bolts which will be used as guide pins to keep the Sub-Frame located whilst it is lowered.

This is one of the original Sub-Frame bolts removed to assess the bolt size, which was M12 x 1,5 x 86.5.

The author found it hard to get M12 x 1.5mm pitch long bolts so manufactured some using existing old stock (bolts from tail shaft refurbishment) welded together to make the required 250mm length.

The next picture shows two of the four the guide bolts installed and the Sub-Frame lowered.

Rear Shock Absorber - Rubber Lower Bushes

Temporary Fix - Rubber Lower Bushes

A quick temporary fix is to make a slit in the rubber seal and inject some oil.

Full Replacement - Rubber Lower Bushes

Reference: WIS AR32.25-P-1871M Replace rubber mounts of rear shock absorbers

Designations - Rubber Lower Bushes

Removal - Rubber Lower Bushes

1. Empty suspension strut (4) of rear axle using STAR DIAGNOSIS.
2. Partially remove spring control arm (1). TIP: Unhook exhaust system on both rear exhaust-rubber mounts. TIP: Detach spring control arm from rear axle carrier and swing downwards.
3. Remove rubber mounts (2) using extraction and insertion tool (01). AIRmatic Lower Rubber Bushes - Rear Suspension

   

4. Clean and check bearing seat (3).

Installation - Rubber Lower Bushes

1. Install rubber mounts (2) using extraction and insertion tool (01). TIP: Do not squeeze plastic parts (large arrow) of the rubber mount (2). Cracked plastic parts result in corrosion and thus to damage to the rubber mount(2).
2. Check installation position of the rubber mount (2). TIP: Carry out visual inspection of distances (small arrows) from outer bearing shell collar (2b) to the bearing seat edge (3k). In the event of unequal distances (small arrows) correct the installation position using the extraction and insertion tool (01).
3. Install spring control arm (1). TIP:Unhook exhaust system on both rear exhaust-rubber mounts.
4. Fill the suspension strut (4) using STAR DIAGNOSIS. TIP: The wheels must not touch the ground while pressurizing because the air spring bellows in the suspension strut (4) will be destroyed if pressurized with the suspension compressed.
5. Check AIRmatic for leaks.

Resources - Rear Suspension

http://www.benzworld.org/forums/w210-e-class/1602887-diy-r-r-outer-bushing-rear.html

http://www.peachparts.com/shopforum/diesel-discussion/338574-notes-r-r-outer-lca-bushings-w124-others.html

http://www.benzworld.org/forums/w201-190-class/1673624-worn-out-hub-carrier-bushing-3.html

http://www.benzworld.org/forums/w220-s-class/1623753-loud-creaking-rear-03-w220-4matic.html

http://www.benzworld.org/forums/w220-s-class/1695182-w220-04-s600-abc-issue-squeaking.html

How to change subframe bushes: http://forums.mercedesclub.org.uk/showthread.php?t=90826 and http://forums.mercedesclub.org.uk/showthread.php?t=90827 .