To grease or not to grease wheel bearings? I have the answer

[entirelyturbo]

It took nearly three and a half years of working at this dealership to finally get an authoritative, straight-from-the-horse's-mouth answer on this issue.

One of our regional reps was at my dealer today (been with Subaru for nearly 40 years) and I asked him what the scoop was with wheel bearings. Do they get greased or not?

He was pretty sure the answer was no. But just to be 100% positive, he called up one of his SOA buddies and had them look into it.

They did some digging, and the answer they gave was: NO.

Now... as you all know, I've been on this rollercoaster ride before. I've replaced wheel bearings on two different 1st-gen Legacies now, and I've gotten conflicting information from a bunch of different sources.

I've dedicated a whole project to it on my car in this thread.

I've ranted and speculated about it in this thread.

The EndWrench article in that second thread is outdated. WAY outdated. As in, from 1993 outdated. So disregard that.

From 2002-on, all wheel bearings come with a sufficient amount of the correct grease in the package. They are ready to be installed and go into service as they come.

So disregard everything I or anyone else has said in the past. I got a definitive answer from the best authority there is: Subaru themselves.

Do not grease wheel bearings prior to installation.

[gijonas]

I got a definitive answer from the best authority there is: Subaru themselves.

Paaalease! I like subaru as much as anyone but cmon now.

[entirelyturbo]

I'm not the Subaru fanboy I once was either, but can you think of a better source?

[gijonas]

I'm not the Subaru fanboy I once was either, but can you think of a better source?

Yes...Yourself

If you have been through this enough and have gathered evidence concerning the results of both actions,what has been best?

There are many things auto manufacturers say that contradict the science of things for many reasons,i wont elaborate as its unnecessary.I just think of things like the fact that if bearings last 15% less time than they could then that proabably equals like another $167,587,345 dollars a year in part sales,without the part being obviously unreliable at the same time.

Dunno just my rant for the day.

[AWD_addict]

if bearings last 15% less time than they could then that proabably equals like another $167,587,345 dollars a year in part sales,without the part being obviously unreliable at the same time.

Cha-ching! Dealers never want to use grease when they're raping you with high prices.

Fahrer- Did you drink the kool-aid? Are you part of the machine?

[suba]

I wouldn't be so quick to assume subaru is just after parts sales here. The logic behind not greasing wheels bearings seems pretty solid to me:

Grease is a great lubricant, but an even better dirt attractor. Wheels (and said bearings) are in probably the harshest conditions on the vehicle with dust, water, dirt, snow, etc. Excess grease pushes out of the bearing and attracts more tiny dirt particles which as the wheels spins and heats up the bearing it tends to mix in with the grease that is inside the bearing itself. You now have tiny tiny dirt particles acting like fine sandpaper on your expensive bearings that wear it away until it gets out of spec and needs replacement again. So ideally the smallest amount of grease possible will stay as contaminant free as possible and protect the bearing from wear for as long as possible, with the kinds of pressures that those bearings see the grease is not 'really' providing lubrication so much as just environment (moisture mostly) protection.

[Buffman]

I had contacted Timken about it when I did my rear one, and they said they come pre-greased with the proper kind and amount of grease and do not need to be greased prior to install.

[SemperGuard]

In my experience, either way is fine.

[Max Headroom]

FWIW, I sold bearings for automotive and industrial use for many years. Prior to that, I had an automotive trade background.

When i got into the bearing industry & went on training courses, one of the subjects which routinely came up was how much grease to put into a bearing during installation. The guiding "rule of thumb" was to fill no more than 20% of the available space with grease.

The reason for this was to avoid something known as "churning" in the case of an over-lubricated bearing, where the grease has nowhere to go as the bearing spins up and actually causes the bearing to overheat.

This is why it appears the new bearings have insufficient lubrication. It's easy to assume that the manufacturer or supplier is looking for easy repeat business. In most cases though, there are sound engineering/lubrication reasons for both the type and quantity of lubrication.

My $0.02c

[entirelyturbo]

Another thing to consider: if the bearing fails in less than a year or 12,000 miles, then Subaru has to warranty the part. That would cost them money, not you.

Wouldn't it be safe to assume that an underlubricated bearing would fail more quickly than an overlubricated one?

Thus, I don't think Subaru would deliberately sell their bearings underlubricated, as they could easily fail before the parts warranty runs out.

[gijonas]

12,000 miles is very little considering how long a bearing should last.I think the fact that they offer a warranty of 12,000 miles (a number which they decided upon) means little.Ive seen interference fit bearings installed with a hammer before that lasted longer than that....i know cuz i was the one who did it years ago lol.

That said i think the argument is probably in favor of just leaving them alone,its not like its that big of a deal to replace them,and after all i would say that how a car is treated is much more important of a factor in the life of a bearing anyways.Grandma could make a crappily installed bearing last longer than perfectly installed bearing will last on a racecar

[SemperGuard]

They dropped the mileage part a few years ago. It's 12 months/unlimited mileage for parts warranty.

[edgeofvamp]

They are bearings, they spin take their abuse and heat to make you happy. They get old, out of shape and creaky for you.

Then you change them, get over it.

I am not trying to be mean, i drive hard and spend a lot of time sideways in my car and i feel that if they last 2 years, the price is justified.

[xise]

old thread I know but seriously when you press a bearing into the hub any excess grease gets squeezed out, wipe it with a rag and slide the cv through...how would you go about over greasing them? Just so you know the cv sliding through will have all the excess on the spline threads that your wheel nut gets torqued on...so how do you over grease it? there is mere thousands of an inch of clearance and guess what, only the factory amount of grease will fit in there ...if you think the parts place uses the exact amount from the warehouse you are wrong, almost all bearing manufacturers coat the bearing with an oil, not grease for packaging just to prevent rusting while they sit there on a shelf....please grease your bearings with a thin coat before install, they will last longer...trust me lol.

Think about it you call a manufacturer and ask them if they are good to go ut of the package...they are in the biz of selling bearings, you coat a bearing in grease and it lasts 3-5 years depending on how hard you drive, or throw it in dry and it lasts a year if you are lucky.....treat your car like you would treat a woman, do your car a solid and trow some lube on it!

[evolutionmovement]

Mine are still original. It might not have moved in 6 yrs., but that's still 260k+ miles & 16 yrs. up to when it was parked, speeds up to around 130, New England winters, water crossings up to the hood line, and sideways enough that the e-brake handle is purely cosmetic even at the limit of adjustment. They were still fine when I parked it (though I wouldn't be surprised if they're a problem when I finally get it going again). Unless it's a competition vehicle, only 2-5 yrs. sounds like expectations for Eurotrash cars.

[Legacy777]

I've unstuck this thread, but added it to sticky compilation thread.

http://bbs.legacycentral.org/viewtopic.php?f=8&t=49582