Repacking New Wheel Bearings... Opinions???

[JeffS]

Oh boy... I know I'm asking for trouble with this one but here goes...

I'll be running an 818 street only.... no track days, no enduro runs, no racing up Mount Washington.

I've got brand new OEM front wheel bearings from Somerset Subaru... (thanks Jason) that came carefully wrapped and pre-packed with a clear looking grease.

Several NASIOC threads on wheel bearing replacement state emphatically that re-packing the bearings with new/different grease is NOT a good idea and a complete waste of time. Other threads say just the opposite.... you risk early bearing failure UNLESS you replace that crappy factory grease with good stuff... and lots of it.

The more I read, the less I believe. Anyone care to chime in on this one? And if you do re-pack, what grease do you use?

[D Clary]

I always repack them with redline synthetic wheel bearing grease. I have had new bearing failure in the past but I do not use oem bearings (sorry Jason)

[STiPWRD]

I also just bought new oem front and rear bearings and a jar of redline synthetic CV2 grease ($14 from JEGS). My plan is to replace any grease that comes with the bearings but I don't have much experience with this stuff either. We'll see how it goes. My goal is mostly street use as well.

[Evan78]

I've never really looked into it, but I've only had to replace 2 wheel bearings in my Subarus over this history:

2002 WRX: Purchased new, sold at 135k miles
2005 Legacy GT: Purchase at 60k miles, currently at 165k miles

Pretty small sample, but that is 240k miles combined. The WRX saw 7 track days and 3 autocrosses and plenty of hard street driving. I wouldn't be surprised to learn that expected life on the street is drastically different than on the track. Tracking probably puts WAY more heat into them from repeated hard braking versus typical street driving.

With that being said, I plan on tracking my 818 and will probably repack with synthetic.

[Desertrunner]

Jeff,
I own a number of Subarus and my guess replace at lest over 10 wheel bearing at different times so I can only speak from my experiance.
I use to beleive that the wheel bearing needed to be cleaned and repacked, that was before I brought a top grade wheel bearing grease and it turned out to be exactly the same as the grease the bearings come in. The grease is sligthly yellow.

What I have learnt is the number one way to stuff the bearing is to use the press and press the cone and bearing on in one step. It marks the cone from the rollers. I put the outter seal on the outter shaft then press the bearing onto that part. Press cone into hub, then partially press all the bits together, then use the axle to pull the lot together in the end. Use a screw driver or a smaller level to pop the outter seal into the hub, Remove drive shaft, install circlip and inner seal and you are ready to go.

One of my Subaru's runs 235 r70 16in which are a large 4 wheel drive tyre and until I changed my method I was forever replacing the bearings.

Tony

[JeffS]

I had a long conversation yesterday with a family friend who was the master machinist and tool room supervisor for the Barden Ball Bearing Company for almost 50 years. He definitely knows a thing or two about bearings.

He did not like the idea of disassembling the bearings because it is critical that parts not get swapped between two different units, or even from side to side within a single bearing. So if you take bearings apart you should only disassemble one at a time, and be very careful to return the ball cages and races back into the side of the bearing they came out of. He said that the axle nut (at 150+ ft-lbs or something like that) does not provide the preload on the bearing.... that's way too much force. The axle nut is tightly clamping the two inner halves together. The mating faces of the two inner halves are lapped until the correct preload on the balls and races is achieved, so the inner halves are a matched set that are individually adjusted for each unit. If you swap pieces from multiple bearings then the preload will not be correct and the bearing will fail very quickly.

I guess that is also the reason I've read that you should never loosen the axle nut with weight still on the tire... the two inner halves of the bearing could be spread apart from the radial load and damage the bearing.

[Evan78]

Tony - do you see much difference in bearing life between a street car and one that spends time off-road?

[Desertrunner]

Evan, I haven't seen a lot of difference on bearing life between off road and street, the bigest differences were if the bearing wasn't fitted right as regards pressing also larger tyres will reduce the life. Even a lot of Subaru mechanics have beed cought over pressing then bearings. It might surprise people to know but the cones are very soft metal and easy to damage so I think the advise Jeff gives is very sound.