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Steering Knuckle Replacement
 
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Pelican Technical Article:

Steering Knuckle Replacement

Steve Vernon

Time:

4 hours4 hrs

Tab:

$450 to $1,000

Talent:

****

Tools:

21mm socket, 21mm, 10mm wrench, E14, E10 Torx, T30 Torx, ball joint splitter, floor jack, jack stands, wheel chocks, safety glasses, lug wrench, torque wrench

Applicable Models:

Mercedes-Benz C250 (2012-14)
Mercedes-Benz C300 (2008-14)
Mercedes-Benz C350 (2008-14)

Parts Required:

Steering knuckle

Hot Tip:

Pre-soak rusted bolts in penetrant oil

Performance Gain:

Better steering

Complementary Modification:

New wheel bearings

Steering knuckles on the W204 connect the tie rods, suspension strut, ABS wheel speed sensor and torque and cross strut to the wheels and brakes. The spindles on the knuckles also carry the wheel hub bearings. If the spindles get damaged you can have all kinds of trouble. The only solution is replacing the knuckles. You will want to get the vehicle's alignment checked after you replace a steering knuckle.

Note: Mercedes considers all of the hardware to be single use only. It must be replaced with new fasteners.

Begin by removing the brake caliper (hang them safely out of the way), caliper mounts and rotors.
Figure 1

Begin by removing the brake caliper (hang them safely out of the way), caliper mounts and rotors. Please see our articles on these procedures for additional assistance.

Next, you will need to remove the wheel hub and bearings (red arrow) from the spindle on the knuckle (yellow arrow).
Figure 2

Next, you will need to remove the wheel hub and bearings (red arrow) from the spindle on the knuckle (yellow arrow). Please see our articles on these procedures for further instruction.

Use an E10 Torx and remove the three screws (red arrows) holding the dust shield in place, and remove the shield.
Figure 3

Use an E10 Torx and remove the three screws (red arrows) holding the dust shield in place, and remove the shield.

There is an ABS speed sensor in the knuckle that needs to be removed by using a 10mm wrench from behind (yellow arrow) and then pulling the sensor (red arrow) out from the back of the knuckle.
Figure 4

There is an ABS speed sensor in the knuckle that needs to be removed by using a 10mm wrench from behind (yellow arrow) and then pulling the sensor (red arrow) out from the back of the knuckle.

Remove the tie rod by inserting a T30 Torx in the top of the tie rod stud (yellow arrow).
Figure 5

Remove the tie rod by inserting a T30 Torx in the top of the tie rod stud (yellow arrow). Then use a 21mm wrench to remove the nut (red arrow).

The ball joints are held in place with a surprising amount of force.
Figure 6

The ball joints are held in place with a surprising amount of force. While you can whack away at the top of the joint with a hammer you really run the risk of bending and/or damaging a part of the suspension. Make sure to use the proper tool; a ball joint separator (red arrow) will make quick and easy work of separating the joint. Note: do not get any part of yourself around the joint when separating, as it has a tendency to let go with substantial force.

Even though you have removed the tie rod ball joint you may want to leave it loosely in the knuckle while you remove the other nuts.
Figure 7

Even though you have removed the tie rod ball joint you may want to leave it loosely in the knuckle while you remove the other nuts. Remove the 21mm nut from the torque strut (red arrow).

Use an E14 Torx and remove the two E14 bolts connecting the rear of the knuckle to the strut (red arrow, one shown).
Figure 8

Use an E14 Torx and remove the two E14 bolts connecting the rear of the knuckle to the strut (red arrow, one shown).

Next, use a 21mm socket and remove the top nut from the knuckle to strut (red arrow).
Figure 9

Next, use a 21mm socket and remove the top nut from the knuckle to strut (red arrow).

Finally, use a 21mm socket and extension to remove the nut on the top of the ball joint on the cross strut (red arrow).
Figure 10

Finally, use a 21mm socket and extension to remove the nut on the top of the ball joint on the cross strut (red arrow).

The knuckle that includes the spindle (yellow arrow) is now free.
Figure 11

The knuckle that includes the spindle (yellow arrow) is now free. You should use a ball joint separator to separate all of the ball joints. If you just start banging away with a hammer you run the risk of destroying the ball joints on the torque and cross struts and will need to replace them. Installation is the reverse of removal. You will need to get the vehicle's alignment checked after you are finished.

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Page last updated: Mon 10/23/2017 03:05:28 AM