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Audi A4 Front Wheel Bearing Replacement
 
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Pelican Technical Article:

Audi A4 Front Wheel Bearing Replacement

Steve Vernon

Time:

5 hours5 hrs

Tab:

$25 to $200

Talent:

****

Tools:

17mm, 7mm Allen, 12mm 12point, large breaker bar or impact wrench, 3 arm puller, bearing puller, slide hammer, floor jack, jack stands, wheel chocks, safety glasses, torque wrench, lug wrench

Applicable Models:

Audi A4 (2002-05)
Audi A4 Cabriolet (2003-06)

Parts Required:

New front wheel bearings

Hot Tip:

Freeze your hubs before installation

Performance Gain:

Properly rolling wheels

Complementary Modification:

Replace ball joints

Are you starting to hear a grinding, wobbling noise coming from your front wheels? Have you noticed a wheel that shakes when you drive? Chances are the wheel bearings may be starting to fail. A faulty wheel bearing can exhibit a few warning signs. The most obvious would be a howling or grinding noise from a front wheel while in motion. This noise would get louder when you steer side to side. You can check for a noisy wheel bearing with the vehicle is stationary too. Jack up the front of your vehicle and rotate the front wheel, while rotating place your hand on the front coil spring. You should be able to pick up a vibration in the spring. There may also be free-play in the bearing. You can check for free-play by jacking up the front of your vehicle and wiggling the wheel up and down. If there is any free-play, replace the bearing.

This article will show you how to replace the bearing by pulling the axle. You have to get the axle out of the way. I find it easier to remove the axle than try and mark the suspension components for reinstallation later; this way you do not need to worry about having your alignment done after the job.

The most difficult part of the job is breaking loose the 17mm self-locking Allen axle nut that holds the drive shaft to the hub. The nut is under a tremendous amount of torque. The simplest way to do this is to use an impact wrench or gun to break the nut loose. Electric impact guns can be purchased inexpensively now and make a great addition to your tool set. If you do not have an impact gun, you can remove the center cap on the front wheel, leave the car on the ground and insert the 17mm Allen through the center. Next, place the largest breaker bar you have on the socket and break the nut loose. I ended up having to put a three-foot pipe on the end of the breaker bar to get enough leverage.

Raise and support front of vehicle on jack stands. See our tech article on jacking up your vehicle. If you are replacing the wheel hub as well, start off by placing it in the freezer. This will help contract the metal and make it easier to press in to the new bearing.

If you do not have an impact gun, you can remove the center cap on the front wheel.
Figure 1

If you do not have an impact gun, you can remove the center cap on the front wheel. Leave the car on the ground and insert the 17mm Allen socket through the center (red arrow). Next, place the largest breaker bar you have on the socket and break the bolt loose. I ended up having to put a three-foot pipe on the end of the breaker bar to get enough leverage. If you do have an impact gun, remove the wheel before using the impact gun on the bolt.

This photo illustrates the 17mm Allen axle bolt (red arrow).
Figure 2

This photo illustrates the 17mm Allen axle bolt (red arrow). Leave the bolt loosely fitted in the end of the axle shaft; you can use it to help push the axle out from the wheel bearing. Make sure you replace this bolt when reinstalling the axle.

The bolts holding the axles in place on our project car were 10mm, 12 points.
Figure 3

The bolts holding the axles in place on our project car were 10mm, 12 points. Make sure to verify the type of fastener and make sure the socket is firmly and completely seated in the head of the bolt before attempting to remove. You do NOT want to strip these bolts. Audi considers these bolts to be single use only and recommends replacing them after each single use.

There are six 12 point bolts holding the axle to the flange.
Figure 4

There are six 12 point bolts holding the axle to the flange. Loosen the six 12 point bolts holding the axle to the flange (red arrow), making sure that the socket is firmly seated in the bolt before loosening. You will need to stop the axle from turning by either having someone apply the brakes or inserting a screwdriver between the disc and caliper.

Some people prefer to remove the heat shield on the right side to give more room to get to the flange bolts and get the axle out from the vehicle.
Figure 5

Some people prefer to remove the heat shield on the right side to give more room to get to the flange bolts and get the axle out from the vehicle. If you want to remove the shield, simply remove the 6mm Allen bolts holding it in place (red arrow, one shown).

With the bolts removed, you can separate the axle (red arrow) from the mounting flange (yellow arrow) and move it towards the front of the vehicle.
Figure 6

With the bolts removed, you can separate the axle (red arrow) from the mounting flange (yellow arrow) and move it towards the front of the vehicle.

Use the 17mm Allen axle bolt and push the axle back out from the wheel bearing (red arrow).
Figure 7

Use the 17mm Allen axle bolt and push the axle back out from the wheel bearing (red arrow).

You can now remove the axle from the vehicle; I find the best way to do this is move the transmission end of the axle (yellow arrow) towards the front of the car and the wheel end towards the rear (red arrow).
Figure 8

You can now remove the axle from the vehicle; I find the best way to do this is move the transmission end of the axle (yellow arrow) towards the front of the car and the wheel end towards the rear (red arrow). Use care when removing as the axles are heavy.

You will need to remove the brake caliper (yellow arrow), pads (green arrow) and rotor (red arrow).
Figure 9

You will need to remove the brake caliper (yellow arrow), pads (green arrow) and rotor (red arrow). Please see our articles on these procedures for additional information.

With the brake system off, you will be left with the wheel hub (red arrow) attached to the bearing in the bearing housing (yellow arrow).
Figure 10

With the brake system off, you will be left with the wheel hub (red arrow) attached to the bearing in the bearing housing (yellow arrow).

If you are just replacing the bearing and reusing the wheel hub, now would be a good time to use a slide hammer (yellow arrow) and pull the hub from the bearing (red arrow).
Figure 11

If you are just replacing the bearing and reusing the wheel hub, now would be a good time to use a slide hammer (yellow arrow) and pull the hub from the bearing (red arrow). If you do not have a slide hammer, you can separate the hub from the bearing with a press or bearing puller, once it is removed from the housing.

The bearing is held in place by four 12m 12point bolts mounted through the back of the housing.
Figure 12

The bearing is held in place by four 12m 12point bolts mounted through the back of the housing. Use a 12mm 12 point socket and breaker bar and remove these bolts (red arrows). Make sure to confirm that the socket is completely set in the bolt, as they are aluminum. You do not want to strip them! Once the last bolt is removed, the bearing and hub will be free so keep a hand on it or it will fall.

All the hardware for this project (17 Allen, four 12mm 12 point bolts) are single use only and must be replaced with new hardware.
Figure 13

All the hardware for this project (17 Allen, four 12mm 12 point bolts) are single use only and must be replaced with new hardware. Most new bearings will come complete with new hardware, but double check when ordering.

With the bolts removed, remove the hub and bearing (red arrow) from the bearing housing (yellow arrow).
Figure 14

With the bolts removed, remove the hub and bearing (red arrow) from the bearing housing (yellow arrow).

Make sure to clean the bearing housing area of any dirt, debris or corrosion (red arrow).
Figure 15

Make sure to clean the bearing housing area of any dirt, debris or corrosion (red arrow). You want to give the new bearing a clean and flat surface to mount to.

With the bearing and hub out of the housing, you can press the old hub out and either re-use it, if it is in good shape, or press a new bearing and hub together and install them back into the housing.
Figure 16

With the bearing and hub out of the housing, you can press the old hub out and either re-use it, if it is in good shape, or press a new bearing and hub together and install them back into the housing. When pressing the old hub out and the new hub in, always make sure to apply force to the correct area. The hub sits inside the bearing (yellow arrow). The hub needs to be properly supported. On older style bearings make sure to support the inner race of the bearing and do not use the hub flange (red arrow) as a support point for the press. If you do not support the inner race and use the hub as a mounting point, you will end up pressing out the inner race of the new bearing and destroying it. Installation is the reverse of removal. Do not forget to use new single use hardware where applicable


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