Mark P

So I decided to replace all 4 of my bearings that have 143k miles on them. More of the story leading up to that here:
<a href="http://ctny.audiworld.com/mark/s4/maintenance/engine_pull/" target="_blank">http://ctny.audiworld.com/mark/s4/maintenance/engine_pull/</a>

I tried using the Hub-Shark to remove my old wheel bearing, but that wasn't going to happen, so I decided to pick up a shop press instead. Even with the press, the bearing housing didn't want to easily move in/out of the spindle/upright.
<img src="http://ctny.audiworld.com/mark/s4/maintenance/wheel_bearing/front/dsc03183.jpg">

<img src="http://ctny.audiworld.com/mark/s4/maintenance/wheel_bearing/front/dsc03185.jpg">

I'm not sure if Piggie made a mistake when writing up the A4 Tech article, as he stated the bearing removed towards the *inside* of the car. On both a '97 A4 and my '02 S4, we have found the bearing to be removed to the *outside* of the car. Perhaps some year A4's were different? Nonetheless, for the S4 guys, they remove towards the outside.

Here's 2 new front bearings and 2 new rear ones. They each came as a kit with the correct bolt. The front kit included circlips for some other car application, not for use in the S4.
<img src="http://ctny.audiworld.com/mark/s4/maintenance/wheel_bearing/front/dsc03254.jpg">

First I pressed out the hub from the bearing. You can see here where the hub has moved down about 1/4" (when I stopped to take this photo):
<img src="http://ctny.audiworld.com/mark/s4/maintenance/wheel_bearing/front/dsc03188.jpg">

After pressing it all the way though, you can see that half of the inner section of the bearing came out with the hub (typical):
<img src="http://ctny.audiworld.com/mark/s4/maintenance/wheel_bearing/front/dsc03189.jpg">

Here's what the bottom/outside of the bearing now looks like:
<img src="http://ctny.audiworld.com/mark/s4/maintenance/wheel_bearing/front/dsc03190.jpg">

I then placed the spindle with the outside facing down, on a flat surface (note in the photo above that the bearing is recessed about 1/8", so placed flat it will have room to move), and pressed it until it broke free.

I used round discs like this just the right size to press on the bearing, but not the spindle. (Also note this photo is just for illustration as I already had pressed out the hub by this step):
<img src="http://ctny.audiworld.com/mark/s4/maintenance/wheel_bearing/front/dsc03187.jpg">

Once the bearing broke free, you could then see the gap between the bearing and the inside lip that it sits against when in place:
<img src="http://ctny.audiworld.com/mark/s4/maintenance/wheel_bearing/front/dsc03191.jpg">

Further out shot showing that it presses from inside out:
<img src="http://ctny.audiworld.com/mark/s4/maintenance/wheel_bearing/front/dsc03192.jpg">

I then supported the spindle from the sides, so I could press the bearing out and through:
<img src="http://ctny.audiworld.com/mark/s4/maintenance/wheel_bearing/front/dsc03197.jpg">

Close-up from the inside:
<img src="http://ctny.audiworld.com/mark/s4/maintenance/wheel_bearing/front/dsc03196.jpg">

Close-up from the outside:
<img src="http://ctny.audiworld.com/mark/s4/maintenance/wheel_bearing/front/dsc03200.jpg">

Here's the old bearing and a new one:
<img src="http://ctny.audiworld.com/mark/s4/maintenance/wheel_bearing/front/dsc03255.jpg">

To separate the inside of the bearing from the hub, I placed the hub in a vise and used a small chisel at the abutment between the two parts. Rotating as I went, the parts strarted to separate:
<img src="http://ctny.audiworld.com/mark/s4/maintenance/wheel_bearing/front/dsc03201.jpg">

After that, it's a few more bangs and it's off:
<img src="http://ctny.audiworld.com/mark/s4/maintenance/wheel_bearing/front/dsc03202.jpg">

Note that the hub has two different outside diameters. Likewise the bearing has two different inside diameters. Be sure to observe this and orient all parts together before pressing the bearing into the spindle, othwise you'll have to press it out again. Here you can see that in this photo the top side has the wider ID, and the lower side has the narrower ID:
<img src="http://ctny.audiworld.com/mark/s4/maintenance/wheel_bearing/front/dsc03258.jpg">

Here they both are in the orientation they fit together. Wider on bottom, narrower on top:
<img src="http://ctny.audiworld.com/mark/s4/maintenance/wheel_bearing/front/dsc03261.jpg">

Since the larger diameter is on the outside edge of the hub, then the bearing gets pressed in accordingly, with the larger diameter on the outside; as pressing the bearing in from the outside-in.

When putting everything back together, first press the bearing into the spindle (with the wider ID facing out/up). When doing so, only place pressure on the outside rim of the bearing (or flat across the full face). Pressing only on the middle will damage the bearing.
<img src="http://ctny.audiworld.com/mark/s4/maintenance/wheel_bearing/front/dsc03262.jpg">
*insert photo w/ bearing later*

Once the bearing is firmly seated against the lip on the inside edge, then the hub can be pressed into the bearing. It is extremely important at this step to support the bottom of the bearing when pressing in the hub. If you only support the spindle, pressing in the hub will blow apart the inside of the bearing, similar to when it was pressed out originally.
*insert photo showing support of bearing &amp; hub pressing in*

All pics here:
<a href="http://ctny.audiworld.com/mark/s4/maintenance/wheel_bearing/" target="_blank">http://ctny.audiworld.com/mark/s4/maintenance/wheel_bearing/</a>

crew219

the lip should have indicated which way the bearing was going to be pressed.

Next time, I'd also lubricate the bearing and carrier a bit with some grease or oil, just to help ease it in.

Dave

FixedWing

Very nice write-up! Guess you're going to have to go out and get some winter tyres now. :-p

rickyS4

Looks similar to the rear bearing steps.

DAP@EPL

The hubshark was flexing and the bearing wasn't moving.

Christian (Stage Ow)

Nice writeup! Did you do some cleaning of the hub/spindle?

Fast Euro

How much does something like this run you if you have a mechanic do it?

Mark P

but that was likely more due to the rigidity of the frame. A lot of pressure would build and then it would move in 1/8" increments, with a decently loud bang each time.

1000 ft-lb 3/4" drive IR:
<img src="http://www.audisscott.com/hubshark/CIMG0102.jpg">

However, I decided to just go at it with the breaker bar and 3' extension. The hub shark was bending with some serious pressure on it, so I dedided to stop there, and just press all 4 out. You can see what we went through last time at the link below:<ul><li><a href="https://forums.audiworld.com/a4/msgs/2282516.phtml">https://forums.audiworld.com/a4/msgs/2282516.phtml</a</li></ul>

crew219

by using a 1/2" breaker bar with a jackhandle on the end. Still sounds a bit like the impact wasn't strong enough.

Dave

Mark P

$300/wheel parts&amp;labor as quoted locally to a friend.