Remove/install front axle half

AR33.10-P-0200RT

Remove/install front axle half

11.02.2019

Model

251

Modification notes

02.02.2011

Final tightening in K0 position added

Operation step 14

Shown on vehicle without AIRMATIC (Air suspension with level adjustment and Adaptive Damping System ADS) code 489 with 4MATIC

1

Front-axle half

2

Cable tie

3

Screw

4

Front axle shaft collar nut

5

Clamp

6

Bolts

7

Floating caliper

Shown on vehicle without AIRMATIC (Air suspension with level adjustment and Adaptive Damping System ADS) code 489 with 4MATIC

8

Bolts

12

Screw

9

Torsion bar

13

Screw

10

Lower transverse control arm

14

Spacer washer

11

Screw

Shown on vehicle without AIRMATIC (Air suspension with level adjustment and Adaptive Damping System ADS) code 489 with 4MATIC

1

Front-axle half

15

Extraction and insertion tool

16

Nut

17

Threaded connection

18

Nut

1

Front-axle half

 

Remove/install

 Warning

Risk of injury. Moving parts can pinch, crush or, in extreme cases even sever extremities.

No parts of the body or limbs should be within the operating area of mechanical components when moving components.

AS00.00-Z-0009-01A

 Danger

Risk of death caused by vehicle slipping or toppling off of the lifting platform.

Align vehicle between vehicle lift columns and position the four support plates at the vehicle lift support points specified by the vehicle manufacturer.

AS00.00-Z-0010-01A

Topical note

Notes on installing brake hoses

AH42.10-P-9406-01A

Topical note

Notes on self-locking nuts and bolts

AH00.00-N-0001-01A

1

When working on the front-end assembly, be careful not to scratch, mark or notch the surfaces of aluminum parts. Otherwise the service life of the parts will be affected

 Removal: The right front-axle half is removed analogously to the described left front-axle half.

 Installation: Only tighten nuts and bolts of suspension components when vehicle is in a ready-to-drive condition.

2

Raise vehicle using two-post lift

AR00.60-P-1000RT

 Raise vehicle until wheels are free of ground.

3

Detach left front wheel and tire assembly



AP40.10-P-4050RT

4

Unscrew collar nut on front axle shaft (4)

 Vehicles with 4MATIC.
For counterholding purposes an assistant must apply the brake.

 Installation: Actuate the brake pedal several times so that the pistons of the floating brake caliper (7) contact the brake pads and the brake pads are pressed onto the brake disk.

 Collar nut, front axle shaft to front axle shaft flange

*BA33.30-P-1001-02E

5

Raise vehicle using two-post lift

AR00.60-P-1000RT

 To half height.

6

Cut off cable tie (2)

 Installation: Pay attention to installation position.

 Installation: Replace cable tie (2).

 Pliers

*164589013700

7

Remove screw (3) and remove left front rpm sensor from steering knuckle

 Installation: Replace screw/bolt(3).

 Self-locking bolt, front axle rpm sensor to steering knuckle

*BA42.30-P-1001-01I

8

Remove clamp (5) from floating brake caliper (7)

 Remove clamp (5) carefully in order to prevent it from springing out!

9

Remove plastic caps over screws (6), remove screws (6) and remove floating brake caliper (7)

 Secure brake pads against falling down.

 From this point, do not operate brake pedal any more in order to avoid pushing the piston out of the left floating brake caliper (7)!

 Installation: Push both pistons of the floating brake caliper (7) together with the pusher tool and insert brake pads correctly. Replace screw/bolts (6). Do not twist brake hose!

 Guide pin to brake caliper support

*BA42.10-P-1002-10L

 Resetting device

*000589524300

10

Swivel floating brake caliper (7) out of working area and fasten with a cable tie to left upper transverse control arm

 Do not damage brake hose.

11

Raise vehicle using two-post lift

AR00.60-P-1000RT

 Raise vehicle to full height.

12.1

Detach lower engine compartment paneling

Vehicles with gasoline engine.

AR61.20-P-1105RT

12.2

Remove soundproofing

Vehicles with diesel engine.

AR94.30-P-5300RT

13

Remove screws (8) and swivel torsion bar (9) downwards

 Remove torsion bar (9) carefully as it is under tension!

 Bolt, stabilizer bar bracket to axle/engine subframe

*BA32.35-P-1001-01C

14

Remove screw (11) and screw (12)

 Mark installation position from rear bearing bracket of lower transverse control arm (10) to front axle carrier before screw (11) and screw (12) are removed.

 Installation: Align with the marks made previously. When installing new parts, the markings must be transferred to the new parts. This ensures that the approximate original adjustment position is reached.

 Bolt, lower transverse control arm at inside rear to front axle carrier

*BA33.20-P-1005-01L

15

Remove screw (13)

 Installation:
Final tightening if vehicle is on measuring platform or in K0 position.
In order to prevent placing rubber bushing under stress.

 Installation: Ensure that the shim (14) is arranged in the position shown.

 Self-locking nut, lower front transverse control arm to front axle carrier

*BA33.20-P-1004-01L

16

Attach extraction and insertion tool (15) and loosen left front axle shaft from left wheel hub

 Vehicles with 4MATIC.

 Extraction and insertion tool

*210589034300

17

Unscrew nut (16) and remove left tie rod from left steering knuckle

 Self-locking nut, tie rod to steering knuckle

*BA46.40-P-1002-01L

 Thrust piece

*140589006300

 Puller

*140589093300

18

Disconnect threaded connection (17)

 Self-locking nut, shock absorber to wishbone

*BA32.25-P-1002-01H

19

Unscrew nut (18) and remove steering knuckle from upper transverse control arm

 Secure front-axle half (1) using suitable means.

 Obtain assistance from a second person.

 Self-locking nut, upper ball joint out of upper transverse control arm to steering knuckle

*BA33.20-P-1001-01L

 Thrust piece

*140589006300

 Puller

*601589043300

20

Remove front-axle half (1)

 Obtain assistance from a second person.

 The shim (14) must be inserted correctly if the lower transverse control arm (10) is reinstalled.

 Installation: Arrange shim (14) in the position shown.

21

Install in the reverse order

 Danger

Risk of accident when commissioning the vehicle due to a lack of braking effect when the service brake is operated for the first time after repair work.

Before starting the engine, actuate brake pedal several times until pressure is built up and maintained in the brake system.

AS42.50-Z-0002-01A

22

Operate brake pedal several times so that the correct brake system function is ensured

23

Perform wheel alignment check

AR40.20-P-0200RT

 Front axle shock absorber

Number

Designation

Model 251

BA32.25-P-1002-01H

Self-locking nut, shock absorber to wishbone

Nm

265

 Stabilizer

Number

Designation

Model 251

BA32.35-P-1001-01C

Bolt, stabilizer bar bracket to axle/engine subframe

Nm

50

 Wheel control, hub

Number

Designation

Model 251

BA33.20-P-1001-01L

Self-locking nut, upper ball joint out of upper transverse control arm to steering knuckle

Stage 1

Nm

20

Stage 2

°

90

 Wheel control, hub

Number

Designation

Model 251

BA33.20-P-1004-01L

Self-locking nut, lower front transverse control arm to front axle carrier

Nm

270

 Wheel control, hub

Number

Designation

Model 251

BA33.20-P-1005-01L

Bolt, lower transverse control arm at inside rear to front axle carrier

Nm

250

 Front axle shaft

Number

Designation

Model 251

BA33.30-P-1001-02E

Collar nut, front axle shaft to front axle shaft flange

Stage 1

Nm

250

Stage 2

°

45

 Front axle brake caliper

Number

Designation

Model 251 (except 251.077/177)

Model 251.077/177

BA42.10-P-1002-10L

Guide pin to brake caliper support

Nm

55

30

 Front axle rpm sensor

Number

Designation

Model 251

BA42.30-P-1001-01I

Self-locking bolt, front axle rpm sensor to steering knuckle

Nm

8

 Tie rod

Number

Designation

Model 251

BA46.40-P-1002-01L

Self-locking nut, tie rod to steering knuckle

Stage 1

Nm

45

Stage 2

°

90