BENZ 原廠技術通報 W204 C300

Grinding noises from area of front axle - wheel bearing defective -

Topic number	GI33.20-P-046670
Version	6
Design group	33.20 Wheel location, wheel hub
Date	12-02-2011
Validity	Model 204 except 4MATIC; except 204.9## (GLK), 207
Reason for change	Linked operation items added!

Complaint

Grinding noises from area of front axle - wheel bearing defective

Cause

Corrosion spreading under wheel hub sealing ring. Dirt and water are washed in front of the sealing ring of the wheel hub via the rpm sensor bore in the steering knuckle or through corresponding gaps between the anchor plate and steering knuckle. Corrosion forms on the contact surface of the sealing ring and spreads under the sealing lips. As a result, moisture can penetrate the wheel bearing and cause corrosion.

Remedy

Please note the revised procedure for repair in the case of wheel bearing damage on the front axle!

The most important new feature of the repair method is the use of a repair hub (Figure A) with inserted stainless steel race (1).

The stainless steel race (1) is pressed onto the corroded steering knuckle (Figure D) during assembly of the wheel hub and guarantees the new seal with the wheel hub sealing ring. This means that it is no longer necessary to replace the steering knuckle!

Axle alignment is not necessary with this repair method!

In order to avoid follow-up repairs, always replace both wheel bearings on the front axle in problem vehicles!

First-time installation of a repair wheel hub:

1.) Detach wheel hub, bearing and brake cover plate.

2.) Use a wire brush to remove loose corrosion from the contact surface of the wheel hub sealing ring (Figure C).

3.) Clean steering knuckle spindle thoroughly.

4.) Install new brake cover plate (Figure E) with optimized sponge rubber (picture 2).

5.) Push on repair hub (Figure A) without tilting it and pull as far as the stop with the clamp nut (Figures G,H,I)

6.) Adjust wheel bearing play (Figure J).

7.) Install sponge rubber ring (Figure F) on rpm sensor.

8.) Reassemble the vehicle.

Important note for subsequent reinstallation of a repair wheel hub:

When the repair hub with stainless steel race is installed, the stainless steel race is positively pressed onto the steering knuckle (Figure D).  

If the wheel hub is subsequently removed/reinstalled, there is a risk of damaging the sealing lip of the wheel hub sealing ring when pushing on.

For this case there is a repair kit (Figure B), consisting of a wheel hub sealing ring with preinstalled stainless steel race.

This repair kit must be pulled into the wheel hub which is to be reinstalled.

To do this, use the regular tool W203 589 0243 00, but with a different method.

As the stainless steel race reduces the inside diameter of the hub sealing ring, the tool die (Figures M, N, picture 4) must be turned through 180° so that the hub sealing ring contacts the rear face of the tool die (the side not lined with rubber).

1.) Insert wheel hub sealing ring with stainless steel race into wheel hub by hand. This centers the hub and makes it easier to pull in with the tool.

2.) Pull in wheel hub sealing ring with stainless steel race using rear face of tool die of special tool W203 589 0243 00.

3.) Remove old stainless steel race from steering knuckle (as shown in Figures K, L).

4.) Push on wheel hub without tilting it and pull as far as the stop with the clamp nut.

6.) Adjust wheel bearing play.

7.) Reassemble the vehicle.

Note:This new repair method will soon (expected as of Week 19/2010) also be available in SDmedia

File	Designation
Anhang.pdf	Attachment

WIS references

Document number	Title	Note	Allocation
AR33.20-P-0310cw	Remove/install front wheel hub		Remedy
AR42.30-P-0712cw	Remove/install left or right front rpm sensor		Remedy
AR33.20-P-0310-03SX	Install radial sealing ring in front wheel hub		Remedy

Symptoms

Symptom

Chassis/suspension / Chassis, noises / Humming/droning/throbbing

Chassis/suspension / Chassis, noises / Howling

Chassis/suspension / Axles / Front axle / Front axle, noise / Squeaking

Parts

Part number	ES1	ES2	Designation	Quantity	Note	EPC	Non-EPC
A2044202544			Brake cover plate, left	1	Improved rigidity to prevent cracking	X
A2044202644			Brake cover plate, right	1	Improved rigidity to prevent cracking	X
A2043350080			Sponge rubber ring for rpm sensor	2	Sponge rubber rings are available with and without white adhesive foil. If the adhesive foil is present, it must be installed on the cable side (Figure E6).	X
A0029890051			Wheel bearing grease	1	Order with quantity index 10! A 002 989 00 51 10	X
A2204230071			Bolt, brake cover plate	6		X
A2043300625			Repair wheel hub	2		X
A2043300060			Repair kit, wheel hub sealing ring with stainless steel race	1	As required	X

Operation numbers/damage codes

Op. no.	Time	Damage code	Note
Operation text
33-2380		3322436
REMOVE/INSTALL FRONT WHEEL HUB (BOTH), REPLACE SEALING RING(S) (WHEEL(S) REMOVED)
42-3600		3322436
REPLACE WHEEL BRAKE SHIELD ON BOTH SIDES OF 1ST AXLE (WHEEL BEARING REMOVED)
40-1590		3322436
REMOVE/INSTALL WHEELS (2)
42-9889		3322436
REPLACE SEALING RING OF RPM SENSOR (BOTH) OF FIRST AXLE FOR ELECTRONIC STABILITY PROGRAM (ESP)