Another bad wheel bearing

[Shane Brittle]

My MY00 Impreza Sportswagon (Outback) has developed a loud humming sound
over the past month.

The mechanic confirmed my suspicion this morning - rear left wheel bearing
is shot. This is the second time. I had this bearing replaced under warranty
at around 40 000kms, now I've just clocked over 60 000kms and its gone bad
again and the car is no longer covered by warranty. Bugger!

Shane

 

[Edward Hayes]

Make sure that your replacement is the new approved roller bearing. It has
been stated that the ball is good but the assembly procedure distorted the
bearing race causing some failures. My 2000 Forester with rear balls has
61,000 miles and no problems YET. eddie

 

[Carl 1 Lucky Texan]

Folks are replacing those with a Legacy bearing that is roller, not ball
(IIRC).
I believe someone posted the part#s on the forum at www.usmb.net .If it
doesn't show in a search there, maybe someone here knows?

There is also real possibility of damaging the new bearing when it is
installed, very tricky. Also, to make matters worse, there is some
controversy about replacing the shipping grease or not.

if you want to cover all the bases, try searching at www.nasioc.com and
www.i-club.com too.

Print out the pertinent stuff, take it back to your dealer, and tell
them to fix it right this time.

Carl
1 Lucky Texan

 

[al gu]

sounds like it was not installed correctly.
bearing pre-load and final torque is very important

 

[Gilles Gour]

sounds like it was not installed correctly.
bearing pre-load and final torque is very important

Hi, could you explain a little more what you mean by
«bearing pre-load»? Thanks in advance.
Gilles

 

[Greg]

I would suspect that the previous install was faulty as when Subaru replaced
my left front at 80K and the replacement lasted only 20k more, just enough
to get me out of my 100k Subaru Gold warranty.

 

[Rick Courtright]

I would suspect that the previous install was faulty as when Subaru replaced
my left front at 80K and the replacement lasted only 20k more, just enough

Hi,

Please let me ask a stupid question: does Subaru NOT believe in grease
in their wheel bearings?

Here's why I ask--

I see lots of stories and tech bulletins and so forth about Subie wheel
bearing issues. I won't get into what IMO is the ridiculous idea of
continuing to use ball bearings in apps where rollers have proven to be
more appropriate, but will relate my own anecdotal experience.

My '90 Loyale 4wd wagon has rollers in the back, balls in the front. I
bought it used with 209k miles, and the previous owner was less than
religious about his maintenance. The owner's manual specs wheel bearing
inspections and regreasing as necessary at 60k mi (approx 100k km)
intervals. Being a bit of a dummy, I didn't catch that, so it was at
over 300k miles when I started getting a little play in the right rear
wheel and inspected the bearings. That RR bearing was bone dry, to the
point of having that "red rust dust" coming out. The LR had only a tiny
bit of grease, both the fronts "enough" but hardly "too much." Compared
to other cars I've worked on with similar mileage, all of these bearings
appeared to have been "underlubed" from the start.

I added grease to all four, made a note to replace the dry one ASAP and
went on. Well, "ASAP" turned into 10k miles plus before the bearing
actually broke but even so I limped home on it. I replaced it at home,
using "homemade" tools, and later replaced the fronts "just cuz" when I
replaced axles. They weren't noisy, didn't have any play, but the front
end was half apart anyway, so might as well do it all at once. The LR is
still doing fine. The car now has 343k miles.

All this makes the idea of distorted housings and all that, while not
impossible, perhaps improbable compared to the possibility of inadequate
lubrication even on new cars or those replacement installations where it
is warned NOT to add grease to whatever comes in the package.

Any thoughts?

Rick

 

[al gu]

Hi, could you explain a little more what you mean by
«bearing pre-load»? Thanks in advance.
Gilles

sometimes you hand assemble the bearing assembly.
put everything into place after you have pregreased all the outer and inner
races
next you use an inch pound torque meter to compress everything to maybe 100
inch pounds for an example.
next you relax the bearing assembly to zero or loose
next you final tighten the bearing to maybe 20 inch pounds for example of
illustration.
preload just aligns the parts
final sets to correct amount.
my values are for example only
see the manual for the correct values

 

[Edward Hayes]

Subaru doesn't recommend ADDITIONAL grease be added to a new out-of-the box
bearing as the recommended amount of grease is already there. Thirty years
ago you packed your new bearing with a soap based grease. Today the newer
greases require only a film of lubricant. Over greasing will cause excessive
heat, expansion and pushed out and leaking seals which will cause bearing
failure. Subaru states this in one of their papers. eddie