Wheel Bearing Failure - Front Axle

Hello everyone!

Recently, I've noticed a somewhat intrusive, very quiet grinding noise coming from the front of the car fairly often.
Over the past week, it has been getting a little louder each day.
It starts with even the slightest pull to the right in the steering and only becomes clearly noticeable at a speed of approximately 90 km/h (although you have to keep the windows closed, the sunroof shut, turn off the radio, and ideally disengage the clutch).

Today I went to ATU. The mechanic was very friendly and offered to take a look at the issue. However, on the lift, he couldn't diagnose any bearing play or grinding noises.
His assessment: The wheel bearings are okay.

However, I didn't give up that easily and insisted on a test drive together with the mechanic. At first, he couldn't detect anything unusual. After I persuaded him to take it out onto the "highway," he was finally able to hear the noise at speeds above 120 km/h, specifically when taking right-hand turns.

His verdict was: wheel bearing failure!
My speech. And unfortunately, I saw this coming at least two weeks ago, without doing anything about it. Now I'm in a mess. I'm supposed to go on my well-deserved vacation next week, and I also need my car every day right now.
And the order books at ATU are also full.
They want about 175 EUR for the material and installation. What do you think of that price?

Has anyone here ever replaced the wheel bearings on an A3 themselves? What tools are needed to press the bearings out and in? What other specialized tools are required?

By the way, these tires only lasted a little over 140,000 kilometers. That's not very good, is it?
Okay, I admit that all of my vehicle's suspension components have definitely seen some wear and tear, as my car was driven 80% of the time on very winding country roads (essentially dirt paths). The somewhat front-heavy TDI engine probably contributes to increased stress on the front wheel bearings.

Ich glaube nicht, dass ich mich traue mit dem beginnenden Radlagerschaden ca. 2000 km Autobahn zu fahren. Das ist mir zu riskant. What do you mean?

Thank you for your expert advice, well-intentioned suggestions, and opinions.

Regards,
Alex.

Hi Alex,

Quote:

...Today, I went to ATU. The mechanic was very nice and offered to take a look at the issue. However, on the lift, he couldn't diagnose any bearing play or grinding noises. His assessment: The wheel bearings are okay. I, however, didn't give up so easily and insisted on a test drive together with the master mechanic. Initially, he couldn't detect anything unusual. After I persuaded him to take a trip onto the "highway," he was finally able to hear the noise at speeds above 120 km/h, specifically while driving in right-hand curves...

Wheel bearings can also be faulty even without noticeable play; you might not notice anything if you only check them by hand. However, the method described above is reliable.
With a bit of luck, you might notice a "rough feel" when turning it by hand.

Quote:

They want about 175 EUR for the material with installation. What do you think of that price?

Normally, a bearing kit with the axle nut and other necessary parts costs around 50 euros.

Quote:

Has anyone of you ever replaced the wheel bearings yourself on an A3?

Yes.

Quote:

What tools are used to press bearings in and out? What special tools are additionally required?

Standard tools are needed. The axle nut is best loosened with two people, with the wheel attached but the vehicle raised: one person presses the brake pedal while the other loosens the nut (a 1-meter length of water pipe used as a lever is recommended).
The easiest way is to separate the wheel bearing housing from the shock absorber and the axle mount. When doing this, be sure to mark the position of the ball joint at the bottom of the control arm (with a marker or pin), otherwise an alignment will be necessary.
You can then place the expanded wheel bearing housing in a sturdy vise and use a puller, hammer and punch, or other tools to press the wheel bearing out.

After removing any existing components, remove any rust spots and scratches on the relay housing using sandpaper and verschandeln the inside of the relay housing. Otherwise, you may experience problems when installing the new relay.

You build the new bearing by sanding down the outer circumference of the old bearing by 0.5mm and removing an inner ring. Then you can easily press the new bearing along with the old bearing into the warmed housing, which has been coated with graphite grease. It's even easier if you place the new bearing in a plastic bag (with ice!) in the freezer until it's time to install it.

I've also written something on this topic in the articles under "Tips & Tricks."
Pressing ball bearings in/out.
While a more forceful approach can still be used during the expansion of storage facilities, installation is more challenging.
To install a bearing correctly, pressure must only be applied to the outer race of the bearing.
When force is applied to the inner race of the bearing, there is a risk that the ball or roller, or their components, will...
The tread can be damaged, which then leads to a new defect within a very short time.
It is equally important to take extreme care not to damage any seals or gaskets.

A cost-effective method is therefore not to dispose of defective bearings, but rather to remove the inner ring.
and to grind the outer ring by a few hundredths of a millimeter using the grinding wheel.
That gives you a great tool for future renovations and expansions.

To facilitate installation, the bearing seat should be slightly warmed, while the bearing itself should be cooled.
Due to the thermal expansion of the material, it will slide in more easily.
When installing something like a shaft into a bearing, the same principle is applied, ideally using the inner ring of the bearing if possible.
Warm slightly, let the wave cool down.
Graphite grease is an excellent lubricant for installation purposes, and it's particularly useful in challenging situations like car wheel bearings.
they can then be easily and gently placed into their seat.

The surfaces of the bearing seat and shaft must, of course, be in good condition; any roughness created during removal will vary depending on...
The severity of the damage can be removed using a file or abrasive cloth.

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By the way, these tires only lasted a little over 140,000 kilometers. That's not very good, is it?

Hmm, the left one lasted 80,000 km, and the right one needed to be replaced at 100,000 km.

Best regards, Rainer.

Thank you for your tips!

The new front left wheel bearing is installed. The disturbing noises are gone now.
I had the tire change done at Pit Stop (due to lack of time) and it cost exactly €91.16. The dealership wanted about €170 for the same service.

I had the old wheel bearing installed in my car so that I would have a base for manufacturing a punch for future projects.

@Rainer:
Wenn ich mir Deine Lagerlebensdauer so betrachte, dann müsste mein rechtes vorderes Radlager wohl in 20-30 tkm fällig sein. BI'm already excited!

Regards,
Alex.

Hello,

It's also possible that your team will win.
"In my two defective rear lights, the seals had failed, and the bearings then stopped working during the winter due to road salt water."
The corrosive liquid had seeped into the interior of the container and formed rust stains there.

Best regards, Rainer.

Rainer K. wrote:

Normal tools. The axle nut is best loosened with two people, with the wheel attached but the vehicle raised: one person presses on the brake, while the other loosens the nut (a 1-meter water pipe used as a lever is recommended).

Hi Rainer,

I would rather advise against loosening the axle nut while the vehicle is raised . In this case, the shock absorber is completely extended, and the forces required to loosen the axle nut are transferred to the upper spring mount in addition to the spring force, which may result in damage .

There are also tools (e.g., eBay) costing around 100 euros that make it possible to remove the bearing with the shock absorber still installed. Unfortunately, I don't know if these tools are any good .

-> impact wrench rules!



CU Gremlin.

It was similar for me: no visible play, but there were noises. The bearing failed at the end of winter, which meant the bearing seal was probably damaged.

The attempt to extract the oil filter housing failed on one side using Rainer's method; the other was completely stuck. Because I was short on time, I packed everything up and took it to a friendly mechanic who extracted the oil filter housings for a fee of €20 each and reinstalled them. The change occurred at approximately 195,000 km. I believe this was the first time they were changed because I acquired the vehicle with just under 70,000 km on the odometer, and I can't imagine that anything related to this would have been replaced beforehand.

Hello Christian,

To loosen the axle nut: The leverage applied through the shock absorber is quite significant, so the shock absorber should be able to withstand it. Ultimately, it depends on how tightly the nut is fastened.
If you want to be on the safe side, loosen the lug nuts a quarter turn while the car is still on the ground, and then finish loosening them after jacking up the car.

I also initially tried using a puller . However, the M12 threaded rod that I was using to pull the wheel bearing out of the housing failed before it reached the bearing... After that, I removed the entire wheel bearing housing. It's easier to get more leverage on a nice anvil.

Best regards, Rainer.

Hello Christian,

...
I also initially tried using a extraction tool. The M12 threaded rod that I was trying to use to pull the wheel bearing out of the housing...

Greetings, Rainer.

Trapez threads should provide a solution and ultimately achieve the desired result.

Hello,

There is a special hydraulic press used for this process, which is performed while the wheel bearing housing is installed.

The handling and assembly are cumbersome; it's designed so that you can immediately remove the entire shock absorber strut and take that part to a press.