Wheel bearing failures (2 now)

[Pearldrummer7]

So I played with the car a bit this weekend, and found my rear driver wheel bearing to be sloppy again. For recollection: that wheel bearing catastrophically failed on my first track day of the year this year. I replaced the entire hub since the race was chewed up.

Now, this was just a random hub with a "fairly new bearing" in it. My first question to you fine folks is this:

Is there any reason or way for premature wheel bearing failures on the same corner with different hubs?

My second question is:

Can I upgrade to the newer cartridge style bearings with my current axles and suspension pieces? What needs to change if not?

[STiPWRD]

I've heard that new wheel bearings sometimes settle after the first few miles of driving, relieving some of the preload on the axle nut. So it's good practice to re-torque them after a few miles and THEN locking the axle nut by hammering in the notch. I replaced all of my wheel bearings and followed this tip.

[UnhipPopano]

If the drive shaft is out of balance or bent, then this type of problem would account for that type of failure. To purchase a device to measure both vibration and frequency is not cheap and replacing it may be less costly. As FF provided the axial, it is probably good. Getting the CV joint apart for inspection will be a pain. Another path to follow is to switch the axials and see if the other bearing fails.

[Hindsight]

If you roll the car on the wheels without the axle nut tightened, it can destroy the bearing. You need to tighten it before lowering the car down to the ground. STiPWRD made a good point too as I have observed this very thing needing to be done while I was at my track day. The rear nut was not at all tight after my first run, even though it was properly torqued before starting the session.

[Pearldrummer7]

I will re check the torque after driving it for the first time. Very good feedback.

I also will switch axles. Shouldn't be interfering tests, and will be telling of the quality of my CV joints/axles.



Thanks guys

[Scargo]

The WRX wheel bearings are not as beefy as the STi's. When my friend went to slicks on his '04 STi it was eating front wheel bearings until he upgraded to '05 sealed bearing for the fronts. I don't know if the same kind of options are available for you on a WRX rear hub.

[Toysrus]

I am not a subaru expert are these taper bearings or roller bearings?
If taper then they are typically torqued in inch pounds very lightly. However After you pack the bearing with grease you need to over torque it to force excess grease out of the way, then back off and put it finger tight then torque in inch pounds. Having them too tight will produce alot of heat and destroy them and likely warp the hub, possibly your rotor as well.

Roller wheel bearings are usually torqued to 100 ft/lbs or more. you torque them to spec and your done. You need a 4 foot cheater bar to torque these things. Put a jack stand next to the hub to support the head of the torque wrench. YouTube is your friend

[freds]

I am not a subaru expert are these taper bearings or roller bearings?
If taper then they are typically torqued in inch pounds very lightly. However After you pack the bearing with grease you need to over torque it to force excess grease out of the way, then back off and put it finger tight then torque in inch pounds. Having them too tight will produce alot of heat and destroy them and likely warp the hub, possibly your rotor as well.

Roller wheel bearings are usually torqued to 100 ft/lbs or more. you torque them to spec and your done. You need a 4 foot cheater bar to torque these things. Put a jack stand next to the hub to support the head of the torque wrench. YouTube is your friend

These are taper roller bearings.

They come in a set that is precisely matched so that the preload is fixed by the inner races coming together when the nut is tightened. It takes a few turns of the axle nut to draw the two inner races together as well as the specified torque to draw/push them together properly. "Over" torquing the nut cannot realistically do any harm, as all you are doing is tying to compress the steel of the inner races. (Hardly possible). You do not add to the force on the roller up against the outer race. Each bearing "set" must therefor be kept together Mixing inner races between sets is a no no..

[Toysrus]

So it looks like this
https://www.google.com/imgres?imgurl...act=mrc&uact=8

Not this
https://www.google.com/imgres?imgurl...act=mrc&uact=8
But like I said not a sub ie expert. I saw a torque spec of 47 ft/lbs if that's the right vehicle so obviously I'm off base on this.

[Pearldrummer7]

It's the first style, for sure.

I remember the torque spec being significantly higher (137 ft*lb?)
https://lh6.googleusercontent.com/-C...S-28-part.jpeg

[Frank818]

160 up front and 140 in the rear.
I've seen variations, say 150-170 up front and 140-160 rear.

[freds]

It's the first style, for sure.

I remember the torque spec being significantly higher (137 ft*lb?)
https://lh6.googleusercontent.com/-C...S-28-part.jpeg

No each wheel bearing looks like the second style, except the Subaru wheel bearings don't have integral oil seals. The outer race is in fact one piece and the two inner races (with opposing tapers)touch in the middle of the outer race, so that you cannot force the inner races harder against the outer race. They stop each other at the correct position for optimum loading. In your picture of style two, you can see the line where the two inner races are in contact with each other.

[freds]

No each wheel bearing looks like the second style, except the Subaru wheel bearings don't have integral oil seals. The outer race is in fact one piece and the two inner races (with opposing tapers)touch in the middle of the outer race, so that you cannot force the inner races harder against the outer race. They stop each other at the correct position for optimum loading. In your picture of style two, you can see the line where the two inner races are in contact with each other.

Here are photos of a WRX rear wheel bearing with only one of the two inner races (the other was toast). I replaced all four of my donor wheel bearings....so I know!

06WRX Rear Wheel Brg.jpg

06 WRX Brgwith one race inserted.jpg

[Toysrus]

Ok I've always called the first on a tapered roller bearing and the second a roller bearing, even though it is tapered internally.

Front proc. Rear proc.
year Model ft-lbs/Nm ft-lbs/Nm
SUBARU - continued
2007-06 B9 Tribeca ......................177 ft-lbs/240Nm 177/240

2006-04 Forester .............................. ..162/220 —

2007 Forester AWD ....................... 162/220 140/190

2006-03 Forester AWD ....................... 140/190 140/190

2002-98 Forester AWD ....................... 137/186 137/186

2007-04 Impreza .............................. ..162/220 140/190

2003 Impreza .............................. ... 140/190 140/190

2002-93 Impreza AWD ....................... 137/186 137/186

1995-93 Impreza FWD ....................... 137/186 SUA

1994-87 Justy .............................. ..... 130/177 SUA

2007-04 Legacy, Outback .................. 162/220 177/240

2003-02 Legacy, Outback .................. 159/216 174/235

2001 Legacy, Outback 2.5L ......... 137/186 174/235

Legacy, Outback 3.0L ......... 159/216 174/235

2000 Legacy, Outback .................. 137/186 174/235

1999-90 Legacy AWD ......................... 137/186 137/186

1996-90 Legacy FWD ......................... 137/186 SUA

1997-92 SVX .............................. .......137/186 138/187

1994-80 All Others 4 W/D ................. 148/200 145/196

All Others FWD .................... 148/200 SUA

That's ftlbs/nm

[Toysrus]

I believe the correct name for subie bearing is a precision bearing. Atleast 1 type of precision bearing.
Correction it's a double row tapered roller bearing.

[Frank818]

Ok I've always called the first on a tapered roller bearing and the second a roller bearing, even though it is tapered internally.

Front proc. Rear proc.
year Model ft-lbs/Nm ft-lbs/Nm
SUBARU - continued

2007-04 Impreza .............................. ..162/220 140/190

2003 Impreza .............................. ... 140/190 140/190

2002-93 Impreza AWD ....................... 137/186 137/186

Bingo.

[Pearldrummer7]

Crap, you guys are totally right. I must've been tired when I looked at those, because I too have replaced these before. I checked torque on it, and it was 137 ft*lb still in the rear, which doesn't really help explain why it failed on me twice now!

[Mitch Wright]

Are you using OEM quality bearings? We have had a similar issue with the Corvettes we use here at the track, using aftermarket wheel bearings and had failures not a problem with the OEM bearings.

[STiPWRD]

Crap, you guys are totally right. I must've been tired when I looked at those, because I too have replaced these before. I checked torque on it, and it was 137 ft*lb still in the rear, which doesn't really help explain why it failed on me twice now!

Did you hammer out the notch on the axle nut to unlock it? If not, it will keep the nut locked and give you a false torque reading since the nut can't rotate. Also, where you re-torquing the failed bearing?

I agree with Mitch about only using OEM bearings. One thing I noticed with these is they aren't exactly bursting with grease so I actually wiped away most of the OEM grease that they come with and generously applied Redline synthetic CV2.

[longislandwrx]

My Subaru dealer repacks them with grease for you for the same reason, they believe they are way undergreased.

[redfogo]

Kinda what most people have said but did you use fresh axle nut each time? They are a one time use kinda item, unless you didn't lock them. What brand of bearings are using? Timken/ Koyo bearings seem to have the best reviews. Last are you using OEM or reman axle stubs? I bought some axle stubs for my front end and one was machined wrong and the bearing kept popping out on me when I turned the car... Once I compared them to an OEM unit I noticed my problem quickly

[Squid1236]

Just my 2 cents but we had simular issues on a CTSV when I worked at the GM proving grounds it turned out we had a bent rear control arm that couldnt be seen until under the CMM it put a good amount of preload on the wheel and destroyed the wheel bearings until we replaced it and did a 4 wheel alignment.