Wheel Bearing Replacement Procedure
 

I just had my left rear wheel bearing replaced(328.00). I had read it on here and maybe another site that one of the reasons for the short life of the bearings was the grease that came with the part was not cleaned off and replaced with a better product. I brought this up to the mechanic at the dealer and he disputed this saying it was high temperature airplane grease which he was taught in tech school. I called another dealer ironically he used to work at and the mechanic there verified what he had said so I went ahead with the service. Does anyone have any real facts on this subject. Others may learn from this as well. An unrelated item can someone tell me the location of the MAF unit. I want to soak it in white vinegar for a few hours as I read in another thread. Thanks to all.

Mike :)

White vinegar??? Good grief. I wouldn't soak it in anything, not even water, for more than a few seconds. Why take chances at ruining something that probably isn't bad to begin with? While the vinegar may or may not cause damage, common sense would indicate that automotive parts and automotive chemicals probably go together. Just like you wouldn't want to put brake clean on your salad.

MAF filaments are pretty fragile. A gentle spray of carb cleaner should rinse just about anything that has come in contact with the filament.

The internet can be equally dangerous as helpful. Try to decipher good from bad before taking the plunge. Ask a few people you trust before risking anything to potentially damaging info. Check their credentials (see below.)

Regarding the grease: I could be wrong but it seems to me that we stumbled across the grease info at a Subaru site, maybe an old TSB or an included instruction sheet that came with a Subaru bearing. Even if not, replacing the grease with other, correctly labeled grease for wheel bearings, couldn't hurt.
It could very well be that your mechanic just didn't want to get any extra grease on his hands...

I just got my 95 back from getting the bearing done. Took my Subie cert. mechanic well, all day friday to get it out and replaced which made me feel much better about my troubles getting the hub off. Total labor was $169 :D .

Here's the best part of it. I had original bearings at 145. He said that the one he replaced had nothing but the packing grease on it and that it wasn't that bad. YES I TOTALLY TRUST HIM. Oh yeah, it still is making pretty much the same rear noise so I'm guessing Chad and Jesse might have made a bad diagnosis. Still totally seems to be coming from the center to me. We'll ignore it for now. :D

Yeah, there was a TSB listed along with pics a long while back, though it may have been in the Yahoo groups. I had the same difficulty convincing the mechanic that did my rear bearing 6 months ago, except he just ignored my request and didn't tell me that he didn't replace the grease until I asked him again after the work had been done.

He does good work, but still has to do things his own way sometimes. Can't blame him I guess, as most mechanics are like that and some can be easily offended when you try to offer info. Next time I'll probably just regrease it myself before taking it in.

KuoH

Wheel bearings
 

Thanks everyone for the feedback. I'll definitely heed the warning about the air sensor and leave it alone. Now that the bearing is replaced and quiet I can hear my stock muffler minus the cats that I had removed. Not very appealing but a Stebro system is on the way. At least its paid for. I don't want to hold my breath from what other members have said about delivery times ;)

If the grease was not the right stuff, the bearing usually go out again in 10,000 miles or so. Hope it was the right grease. :rolleyes: :)

Did ya read my post Earl? Mine was from factory with shipping grease! :D

This was the post I was refering to. Just because the mechanic said that it was ok, doesn't mean that the grease is ok. There are many members here that have heard that before and found themselves back at the shop 10K miles later asking why the awful sound came back. :) ;)

Bearings
 

I know this last set of bearings lasted three times as long as the first two did. Something about changing the housing with the bearing itself. Nothing was ever said by the three mechanics over seven years about using the right grease. In fact my current mechanic was instructed in school that the packing grease that comes with the bearing is the best quality. I think I am going to call SOA if they concur with this.


Mike

It could very well be the 'right' grease, I'm just going by the previously mentioned TSB/SSM. The Subaru bearing I installed Saturday had grease that looked like Vaseline. It actually seemed to be separating, some was beginning to turn to oil. I've used many kinds of bearing grease over the years, including hi-flow, but I've not seen any like that.

That's how the two bearings I ordered came and as I recall, that's a light "packing" grease, used to prevent rust and corrosion during storage. The TSB called for cleaning that off and reapplying normal grease.

KuoH

Here is what I got from subarusvx.org:

The following information was gathered from the www.subarusvx.org website.


The wheel bearings on the Subaru SVX are prone to fail prematurely. The reason for the initial failure is that the original seals allowed water to get into the bearings (the seals have since been redesigned to prevent this). Subsequent failures occur because the proper grease is not used when repacking the bearings AND over tightening of the lateral link bolt and the axle nut.

You need to make sure the mechanic knows how to properly install the wheel bearings. There are 4 technical service bulletins issued by Subaru on proper bearing installation for the SVX!

First, the bearings are made in Japan, they are sent by ship to the USA. Ship travel promotes rust. Rust is a no-no for bearings. To alleviate this problem the bearings are coated in a very light grease for shipping. The contact points between the balls and the race (a race is a circular steel ring that the balls roll on inside the bearing) generates tremendous pressure and heat. Pressure and temperature break down lubricants (oil & grease) so that they no longer function properly. The light shipping grease cannot withstand the pressure and temperature that is generated by the bearing. It breaks down and loses its lubricating qualities (it becomes varnish).


Therefore this shipping grease must be FULLY removed and a good heavy-duty grease should be applied to the bearing before it is installed. This is not always done or done poorly. Therefore the newly installed bearing goes bad rather quickly.

Another problem is using the proper tools to remove and install the bearing (Bigger hammers don't make for better installations). Make sure a bearing press or a hub tamer is used. The surfaces should be cleaned, and checked for "out-of-roundness" (the proper tool for this is a micrometer calipers). Also, just because you bring the car to a Subaru service dept. doesn't mean that they know what to do or have the proper tools. But the odds are better that they do.

Second, all the nuts and bolts must be tightened to exact specifications...over tighten them and you'll be back for more wheel bearings. The proper torque specs for the lug nuts is 72-87 ft/lbs. Most shop impact wrenches are set to around 120 ft/lbs. so this is important.

Thanks John. I will put this memo in the How-To Docs under wheel bearings. :)

TSB # 03-50-02:


...."The new genuine Subaru rear wheel bearings are not to be packed with grease of any kind. The bearing is ready to install out of the box".

According to the bulletin the bearing changes took place in Aug of 01. Prior to this it was neccessary to remove the "shipping" grease and use a high temp grease during installation. There is a similar TSB for the front bearings.
The TSB applies to Forester's, Impreza's and Legacy's. As far as I know, the SVX bearings still need to be repacked. I could be wrong though. Since the STI uses the same rear bearing as the SVX it's possible that Subaru is now packaging those bearings ready to go instead of just using a shipping grease.


Dave

Strange. Original bearings meant that they were installed at the factory. Factory wheel bearings were packed with high temp grease, not shipping grease. Only bearings being shipped had shipping grease. Maybe after 10 years and 145k miles it just looked like shipping grease?



Dave