Front Subframe: Service and Repair

31 11 506 Lowering/raising Front Axle Support (Universal Lifter)

Special tools required:







WARNING: High-voltage system - danger to life.







WARNING:
The following points must be strictly observed prior to starting work:
- De-energise the high-voltage system.
- Observe safety information for handling hybrid cars.







IMPORTANT:
Before lowering front axle support:
Observe safety information for raising the vehicle
In order to avoid damage to vehicle hoist, perform weight compensation on vehicle.
Load spring strut domes with sand bags.







WARNING:
Before lowering the front axle support, you must release the steering shaft on the steering box.
If this is not carried out, the bulkhead steering shaft bearing will be damaged.







Necessary preliminary tasks:
- Remove front wheels.
- Remove stiffening plate
- Remove steering box cover on left and right side.
- Partly detach front left and right wheel arch covers (rear section) at rear area.
- Remove anti-roll bar link from anti-roll bar.
- Unlock plug connection on steering box and disconnect. (Version with active steering)
- Mark steering box on front axle support and release. Pull steering box forward slightly and tie up.
- Secure anti-roll bar on front axle support.
- Loosen the brackets for the engine oil pipes, (depending on version)
- If necessary, disconnect plug connections.
- Secure engine in installation position.







Release screws (1).
Remove front left and right wheel arch cover (2) from bumper trim.

Installation note:
Make sure wheel arch cover is correctly positioned.







Release screws (1).
Remove brake air duct (2).







Release screw (1).
Tightening torque 51 11 6AZ.
Release screw (2) and remove.
Tightening torque 51 11 6AZ
Release front axle support (3) from deformation element (4).







Release screw (1) and remove left and right holder (2).
Expose oil lines.







Undo screws (1) and detach auxiliary water pump from front axle support.
Do not remove auxiliary water pump.







Secure swivel bearing (1) with special tool 33 5 206 on spring strut (2).







Release nut (1) and remove screw.
Remove spring strut from lower wishbone (2).
Tightening torque 31 12 7AZ.







Engage special tool 31 5 251 with a 2nd person helping completely on workshop jack 00 2 030.
Insert special tools 31 5 255 in telescopic supports of a profile rail pair.
Insert special tools 31 5 253 in telescopic supports of other profile rail pair.

NOTE: In a profile rail pair, two profile rails are connected to one another by gearing.







NOTE: The jacking points on the left side are shown.

Align special tool 31 5 253 and 31 5 255 to front axle support.
Support front axle support by operating workshop jack 00 2 030.

IMPORTANT: The centre of gravity of the front axle support must be positioned centrally over the workshop jack.







Release screws (1, 2, 3) from front axle support.
Tightening torque 31 10 1AZ.

Installation note:
Check thread for damage, repair with helicoil thread insert if necessary.

1. = M12x1.5x65 screw
2. = screw M12x1.5x145
3. = screw M12x1.5x95







IMPORTANT:
When lowering and lifting, pay attention to hoses and lines of hydraulic steering/Dynamic Drive depending on vehicle equipment. Hoses/lines must not be kinked/tensioned/bent.
If necessary, release lines and hoses.







Carefully lower front axle support by operating workshop jack 00 2 030.
Lower front axle support by max. 10 cm.







After installation:
- Check lines and hoses for tightness.

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