I'm on my 4th set of bearings on the rear drivers side of a 96 Legacy that's my daily driver. It's converted to FWD, so no rear axles, just the rear CV cups only.

 

Bad luck or is something causing this?

 

Shop that does the local dealers machine work installed the first bearing. Lasting about 15,000 miles so I......

 

Installed an entire used knuckle complete assembly....which lasted about 10,000 miles so I....

 

have another complete knuckle assembly to install tomorrow.

 

Is that just bad luck?

 

Could something *cause* bearing failures besides the obvious like compromised seals and Subaru's terrible newer gen bearings? Like a bad strut or the control arms bent? I see nothing obvious back there and the alignment shop said nothing when I had it aligned a year or two ago.

Edited November 2, 201015 yr by grossgary

My mother-in-law can't wear watches, they just quit running on her.

 

Maybe you have bad mojo, or someone has put a curse on you or the car.

 

Do you have any enemies?

Well, two used assemblies that may have already been damaged or worn. A new bearing that may have been damaged when it was installed, or might have been defective, or just poor quality. Who knows.

I don't complain about used parts going bad though. Who knows what those parts went through with their previous owner.

I recently picked up a full tie rod assembly for my truck out of the junkyard for $12. It looked great, fit tight, wasn't covered in mud or grease or rust like they usually are. I pried and twisted and turned and all the joints were in great shape. They lasted a whole two months of one or two days a week driving. Of course, I then went out and bought the cheapest replacements I could find so I'll be changing them again in a year.

Maybe your torque wrench is out of calibration and you're over or undertorquing the axle nut?

There's actually a service bulletin that I read on Endwrench about this problem. If you overtorque the lateral link bolt (the one that goes through the two links that go parallell to the axle) it deforms the housing and the bearings will burn up. Since that bolt travels out in the open between the two ears of the knuckle it will squeeze the ears together if you crank it down too tight.

 

The legacy bearings aren't junk, they're the tapered roller type. It's the ball bearing rear bearings that fail all the time in the foresters and impreza's. You fix that by upgrading to the legacy bearings which are the same diamter, but a lot more reliable.

Bad strut hammering them by bouncing a lot?!?

 

Hard cornering?

 

I just did one on a '97 SUS not long ago - first one on that car at 212k. He drives pretty hard and corners it pretty tight on a regular basis and has since he bought it at 80k. We put a used one on from the yard but that was only about two months ago....

 

GD

Maybe your torque wrench is out of calibration and you're over or undertorquing the axle nut?

quit calling my arm out of calibration! i've never used a torque wrench on axle nuts. never had a problem before and i've done countless hub swaps, axle swaps, etc. since i have one though i'll put it to use tomorrow for the first time. sounds like a good time to use it.

 

we'll consider this an experiment then - i'm throwing the used hub on there tomorrow and we'll see what happens.

I don't use a torque wrench on them either. The axle nut doesn't set the bearing preload so I don't see any reason to torque them. Is this using the 4WD rear knuckle assembly with just the outer axle joint installed into it or is it using a 2WD Legacy rear setup (which I've never even looked at before ).

 

GD

GD - it is an EJ18, does that answer the hard driving question? nah, i don't do hard cornering. i mean we have really twisty mountain roads here that are pretty terrible so the suspension gets a work out, but i don't push the limits by any means.

 

There's actually a service bulletin that I read on Endwrench about this problem. If you overtorque the lateral link bolt (the one that goes through the two links that go parallell to the axle) it deforms the housing and the bearings will burn up. Since that bolt travels out in the open between the two ears of the knuckle it will squeeze the ears together if you crank it down too tight.

well blow me down, i hope i did overtighten it.....twice? hard to imagine i deformed two different hubs, but worth the torque wrench yet again.

 

The legacy bearings aren't junk, they're the tapered roller type.

junk is probably too strong. i've replaced more EJ bearings in my short EJ experience compared to the much longer older generation experience where i've never had to replace a bearing. no matter, they're really not that big of a deal, they don't leave you stranded.

Is this using the 4WD rear knuckle assembly

yeah, just with a disassembled rear CV cup in place as a holder.

Nice tip on the lateral link bolt. I will remember that. Just might be your issue eh Gary?

 

You monkey-fisted it didn't you?

 

GD

Not using a torque wrench is fine, as for most things I do not either. But If you are having repeated failures, it is time to make sure everything is correct and use a torque wrench.

You monkey-fisted it didn't you?

well, i don't recall but i bet you're right. probably something like "man i'm making sure this thing is GOOD AND TIGHT to make sure i don't loose this one....grrrrr...errrrrrrr."

Torque values for 1996 Legacy FSM:

Axle nut: 137 ft-lbs (AWD and FWD)

Lateral Link bolt: 101 ft-lbs

Trailing link bolt: 72-94 ft-lbs

 

Pretty sure I did this, but it does says to torque the axle nut with the wheel removed:

Always tighten axle nut before installing wheel on

vehicle. If wheel is installed and comes in contact with

ground when axle nut is loose, wheel bearings may be

damaged.

Edited October 30, 201015 yr by grossgary

are you running stock rims and tires? i hear about bearing failure when people use different size rims and tires, apparently it stresses the bearing in a different way than factory tires and rims, i.e. the off set rims to make it set "bow legged" i personally haven't had issues, but just something to think about.

quit calling my arm out of calibration!

 

When I'm working on my BMW, I sometimes use my German torque wrench- "gutentight."

 

Prior to having a torque wrench which read up to 200Ft-lbs, I used to use my body weight, a breaker bar and calculate the weight to length ratio. i.e. if I weight 150Lbs and stand 1ft from the end of the bar, presto, 150Ft-lbs. It always seemed to work pretty well. If you weight less than the required torque and are bad at math, you can always borrow a pet, a kid or a sack of cement for some additional weight.

When I'm working on my BMW, I sometimes use my German torque wrench- "gutentight."

 

Prior to having a torque wrench which read up to 200Ft-lbs, I used to use my body weight, a breaker bar and calculate the weight to length ratio. i.e. if I weight 150Lbs and stand 1ft from the end of the bar, presto, 150Ft-lbs. It always seemed to work pretty well. If you weight less than the required torque and are bad at math, you can always borrow a pet, a kid or a sack of cement for some additional weight.

 

You use a calibrated mamal?

If you need that extra 5 lbs you send out for pizza

I'm beginning to think something is wrong. The newly installed hub sounds lnoisey already, particularly on bumps, humps, turns, etc. It's light, but time will tell...but it seems like the other replacements all did the same thing, started making noise almost immediately after replacement - I forgot about that detail.

 

Got vehicle at 120 - replaced first one at 125k.

Next one at 142k - so it made it 17,000 miles.

Next one at 160k - so it made it 18,000 miles.

 

I'm thinking there's a pattern here. Noise comes back right away and lasts the same mileage twice in a row?

 

So the next question will be what is causing this?

 

One vehicle owner (prior to me), garage kept, no rust. Stock wheels/tire size. No accident that I'm aware of.

 

Knuckle is attached to the strut, lateral link and transverse link, seems like it should be one of those right?

 

I had it aligned a year or two ago and while I don't have the numbers or anything they said it aligned just fine.

In the words of Click and Clack, when was the accident.

You use a calibrated mamal?

 

I will try this with one of the neighborhood cats. Tell me - does it go: wrench, cat, human, or wrench, human, cat...... I am trying to envision how this works and unfortunately it either ends badly for the cat or badly for me......

 

GD

How about you get not only the knuckle/hub from a donor but also the two links and the strut at the same time from the same car and see if there's any difference?

 

This is pretty bizzare..... you sure it's not something to do with the environment in your shop or your transporting/removal technique of the used part?!?

 

Did I mention this is really weird?

 

GD

I will try this with one of the neighborhood cats. Tell me - does it go: wrench, cat, human, or wrench, human, cat...... I am trying to envision how this works and unfortunately it either ends badly for the cat or badly for me......

 

GD

 

Well it goes Wrench uman cat, then the tough part, one or two squirrels.

How about you get not only the knuckle/hub from a donor but also the two links and the strut at the same time from the same car and see if there's any difference?

 

This is pretty bizzare..... you sure it's not something to do with the environment in your shop or your transporting/removal technique of the used part?!?

 

i agree, bizarre. i've done enough hub swaps and bearing jobs that i'm fairly certain it's not anything like that.

 

as for an entire set up that's a great idea. problem is we don't really have any decent pull it yourself yards close enough and most stuff is rusted to 1*!&!@*@* so getting it off with carry in tools is a gamble. i'll call some yards and see if any can grab me the entire thing.

 

maybe someone parting one out here that can grab me the entire thing.

 

i wonder what the newest rear set up is that i could use? that might reduce the rust issues.

Where have you been getting these bearings from? Has there been problems with the axle shaft splines being rusted to the hub splines? Hammering on the axle shaft to free it from the hub splines would easily be enough to comprimise the bearing durring removal..... are *you* removing these or are they comming from a yard where some *non-english-speaking* "dissasembler" is pulling them for you?

 

Do you still have any of the failed bearings around? Cut one open and inspect the damage - what kind of failure is occuring? Brinelling could indicate a failure from "hammering" on them durring removal or installation.... etc.

 

Probably time to get real technical about this problem. Failure analysis is called for....

 

GD

Alos are you driving them in too far?