33 31 000 Removing and Installing Complete Rear Axle Support
33 31 000 Removing and installing complete rear axle support
Special tools required:
WARNING:
Failure to comply with the following instructions may result in the vehicle slipping off the vehicle hoist and critically injuring other persons.
Load the luggage compartment with a minimum of 100 kg before lowering/removing the rear axle support.
When supporting components, make sure that:
- the vehicle can no longer be raised or lowered
- the vehicle does not lift off the locating plates on the vehicle hoist.
IMPORTANT:
Observe safety informations for raising the vehicle
In order to avoid damage to vehicle hoist, perform weight compensation on vehicle.
Necessary preliminary tasks:
- Remove rear wheels.
- Tension both coil springs (and leave on vehicle).
- Remove propeller shaft.
- Expose cable pull for the emergency release up to the rear axle support.
- Disconnect plug connection on actuator unit (EMF).
- Unclip the cable for pulse sensor, brake pad wear sensor or shock absorber from the holders above the rear axle support.
- Disconnect plug connection at both ride height sensors.
- Remove both rear shock absorbers at the wheel carrier (undo clamps for brake hose).
Version with self-levelling suspension:
Deactivate and drain air spring/suspension system
IMPORTANT: Do not use any tools to dismantle the lower section of the air spring (1).
Tilt lower section of air spring (1) by hand towards front/side.
Installation note:
Press lower section of air spring (1) by hand into wheel carrier until it can be seen and heard to snap into place.
NOTE: The picture shows the plug connections on the right side on a vehicle with Vertical Dynamics Management (VDM).
Partially detach rear wheel arch cover.
Only on right side: Disconnect plug connection (1) for brake pad wear sensor and expose cable up to the wishbone.
Disconnect plug connection (2) for pulse sensor and expose cable up to the wishbone.
Version with Vertical Dynamics Management: Disconnect both plug connections (3) for the shock absorbers and expose cable up to the wishbone.
Press brake pedal down to floor and secure with pedal support.
NOTE:
The pedal support may only be released when the brake lines are reconnected.
This prevents brake fluid from emerging from the expansion tank and air from entering the system when the brake lines are opened.
Position an oil sump underneath to catch brake fluid.
Undo retaining screw (1), in the process counter brake hoses (2) at the square head.
Disconnect brake hoses (2) and seal off with seal plugs.
Installation note:
Ensure tension-free routing of the brake hose and sufficient distance to neighboring components.
Tightening torque 34 32 1AZ.
Engage special tool 31 5 250 with a 2nd person helping completely on workshop jack 00 2 030.
Insert special tools31 5 253 in telescopic supports of a profile rail pair.
Insert special tools 31 5 256 in telescopic supports of other profile rail pair.
NOTE: In a profile rail pair, two profile rails are connected to one another by gearing.
The jacking points on the left side are shown.
Align special tool 31 5 256 to opening in rear axle support.
Align special tool 31 5 253 to crossmember arms on rear axle support.
Support rear axle support by operating workshop jack 00 2 030.
IMPORTANT:
The centre of gravity of the rear axle must be positioned centrally over the workshop jack.
Tie down rear axle support 33 5 206 to the special tool using a tensioning strap31 5 250.
Version with ARS:
Remove right underbody panelling (rear section).
IMPORTANT: Pay attention to control lines (2) when lowering and raising. Hydraulic lines must not be kinked/tensioned/bent.
Release retaining screw (1).
Tightening torque 37 14 15AZ.
Remove front and rear compression struts and carefully lower rear axle support.
After installation:
- Activate and fill air spring system
- Bleed brake system.
- Perform start-up for ARS.
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