Drive Shaft Center Bearing Replacement

[Phillip]

I'm getting some bearing noise from the rear of my '99 Outback Wagon that is not a wheel bearing. I suspect the center bearing/support on the driveshaft needs replacing. My service manual is pretty weak; anyone changed one who could give me a few tips? Thanks

[porcupine73]

I think often the suggestion is to remove the driveshaft and take it to a driveshaft/driveline builder/shop for servicing.

[idosubaru]

are you sure it's not the rear differential or the ujoints in the shaft? the center carrier bearings fail so rarely that i would install a used driveshaft, even in my wifes car. and they never "fail" anyway, they always give plenty of warning so in the very unlikely event that your replacement one failed (which won't happen anyway), it wouldn't strand you or cause any problems. another low-mileage used unit can be had for under $100 rather easily and they are super easy to replace.

[Phillip]

No, I'm not sure it's the center bearing, but I just replaced both rear wheel bearings and that didn't change the noise. It's definately a bearing noise that gets louder as the speed increases. I planned to drop the shield and listen to the center bearing housing tonight. I listened for noise on the rear differential housing a few weeks ago, but couldn't hear any roughness or vibration. My service manual says the center bearing is serviced with a new driveshaft. Sure hope it's not the differential as I'm sure it will be expensive.

 

are you sure it's not the rear differential or the ujoints in the shaft? the center carrier bearings fail so rarely that i would install a used driveshaft, even in my wifes car. and they never "fail" anyway, they always give plenty of warning so in the very unlikely event that your replacement one failed (which won't happen anyway), it wouldn't strand you or cause any problems. another low-mileage used unit can be had for under $100 rather easily and they are super easy to replace.

[idosubaru]

rear differentials aren't that expensive. same idea as the center bearings, they don't fail enough to warrant buying new either, which is why used ones are everywhere and can be found cheap, there's no demand. should be able to get one of those for $100 or less as well, probably like $50. be a good excuse to upgrade to a limited slip style, but that's just me!

 

let's get more specific, are you just hearing things or do you feel any vibrations? if you feel anything i would suspect it's a ujoint, they fail more often than the carrier bearings, and there are three of them, not just one....so three times the chance of failure...or however the statisticians calculate that.

 

okay, if you're interested in checking yourself you can crawl under and look at the driveshaft...that will probably fix it. juts kidding, if you get under there you can grab and yank on the driveshaft. sometimes a bad ujoint is detectable under the car. you'll see the metal shearing at the ujoint - it'll look like shiney metal or wearing in an area or you can feel play in the shaft that shouldn't be there. unfortunately you can't really rule out the driveshaft without removing it. the joints can also seize which makes them feel fine, no play, but they do cause noise and vibration. removing the driveshaft isn't all that difficult if you'd like to entertain doing that to see. you can probably just unbolt the carrier bearing (2 17mm bolts i believe) and drop it down. this may give you enough access to see if the bearings are noisey or rough. just spin the bearing around. on some soobs the carrier bearing and axle will drop down and just squeeze through without needing to remove the exhaust, that is nice since then it's only a 2 bolt job. not sure about yours though. the front half of the driveshaft (in front of the carrier bearing) isn't held in by anything, it just slides into the transmission, so with the carrier bearing out it has movement to slide in and out, but i don't believe it will come out all the way if it's still bolted to the rear diff. i wouldn't put a ton of pressure or leave it that way very long though as it slides through a seal where it slides into the trans. although the seal is very easy to replace, just be mindful and you won't need to.

[Reveeen]

Noises "in the back" are real tough to figure out.

I am not discounting you making a center bearing call, but the drive shaft has such limited movement, that need for center bearing replacement is rare.

 

The entire rear end assembly is rubber mounted, inproper jacking/hoisting in the area behind the rear doors can cause noise, as the sheet metal mounts around the rubbers gets crushed.

 

Rear strut mounts (uppers) going bad can be a source of weird noises.

 

"U" joints do go out of these cars.

 

*The dreaded transmission (automatic) torque bind can cause drive line noise.*

[uniberp]

I'm getting some bearing noise from the rear of my '99 Outback Wagon that is not a wheel bearing. I suspect the center bearing/support on the driveshaft needs replacing. My service manual is pretty weak; anyone changed one who could give me a few tips? Thanks

 

 

Have you done a tire rotation recently? Is there any noticeable difference in treadwear front and rear?

 

It may be my imagination, but normal drivetrain noise seems to increase wen fronts wear slightly more than rears. When I bought the Legato, theh fronts were a little more worn, and it kind of lurched at constant speed 45mph and up. I rotated fron to back and rear side to side and it felt much better.

 

Further confirmed this this past weekend, with my GF's Forester, who neglected a rotation for 12-15k miles.

 

It's like it prefers to drag the rear along. Tires are just at .25 circumference difference.

[Phillip]

My service manual says the center bearing is not replaceable and the entire driveshaft must be replaced. Have you had a bearing replaced at a driveshaft shop?

I think often the suggestion is to remove the driveshaft and take it to a driveshaft/driveline builder/shop for servicing.

[Phillip]

That was the first thing I tried. I then replaced both rear wheel bearings (one was definately bad), but still have the noise. I'm guessing either a center support bearing or rear diff. Thanks for the reply.

 

Have you done a tire rotation recently? Is there any noticeable difference in treadwear front and rear?

 

It may be my imagination, but normal drivetrain noise seems to increase wen fronts wear slightly more than rears. When I bought the Legato, theh fronts were a little more worn, and it kind of lurched at constant speed 45mph and up. I rotated fron to back and rear side to side and it felt much better.

 

Further confirmed this this past weekend, with my GF's Forester, who neglected a rotation for 12-15k miles.

 

It's like it prefers to drag the rear along. Tires are just at .25 circumference difference.

[Phillip]

This sounds like a rotating noise - a roaring or rumbling heard pretty loud in the car. I replaced both rear wheel bearings (one was definately bad), but the noise didnt change. My next guess is either the center bearing or rear diff. Thanks for the reply.

 

Noises "in the back" are real tough to figure out.

I am not discounting you making a center bearing call, but the drive shaft has such limited movement, that need for center bearing replacement is rare.

 

The entire rear end assembly is rubber mounted, inproper jacking/hoisting in the area behind the rear doors can cause noise, as the sheet metal mounts around the rubbers gets crushed.

 

Rear strut mounts (uppers) going bad can be a source of weird noises.

 

"U" joints do go out of these cars.

 

*The dreaded transmission (automatic) torque bind can cause drive line noise.*

[porcupine73]

My service manual says the center bearing is not replaceable and the entire driveshaft must be replaced. Have you had a bearing replaced at a driveshaft shop?

I have not had a bearing replaced at a driveshaft shop; I recall seeing it in some threads previously....perhaps with nipper?

[idosubaru]

there's no vibrations at all?

 

if someone else did it, then so can you (or a machine shop). the FSM also states the Ujoints aren't servicable...along with many other items on the car which I and others have done. it can be done, it's a matter of finding a shop that's either done it before or willing to try.

 

for some it's easier to order another shaft and be done with no down time. rather than calling around, asking, finding a place that wants you to bring it in first, sourcing bearings and on and on, which requires removal and down time...etc and depending on prices in your area and the shop won't end up being any cheaper than a used one. all shops i know of charge a minimum of $45/hour with a 1 hour minimum shop charge. i would bet you're looking at 1 hour plus the cost of new bearings - so probably $100 or more. you can get a used one cheaper than that shipped to your door. no down time, calling, asking around, dropping it off, etc.

 

the funny thing is that whether you install a new one or a used one i promise your next issue (if there is one) is with a ujoint, not the used (or new) carrier bearing.

[Phillip]

Maybe a very slight vibration, but not sure. I manage a large municipal fleet shop and have access to a press, etc. Even though the service manual said the shaft wasn't servicable, I planned to give it a try. Nipper thinks it may be the rear diff. I didn't hear any noise when I listened with a stethascope, but it's pretty hard to tell. My center bearing is shielded with a tin cover that I'll need to remove before checkin it out. Whatever it is, the noise inside the car is getting louder. Sooner or later something will break. Hope I figure it out before then. Thanks for the tips. I'll let everyone know what I found (when I figure it out!). Thanks again.

 

Phillip

there's no vibrations at all?

 

if someone else did it, then so can you (or a machine shop). the FSM also states the Ujoints aren't servicable...along with many other items on the car which I and others have done. it can be done, it's a matter of finding a shop that's either done it before or willing to try.

 

for some it's easier to order another shaft and be done with no down time. rather than calling around, asking, finding a place that wants you to bring it in first, sourcing bearings and on and on, which requires removal and down time...etc and depending on prices in your area and the shop won't end up being any cheaper than a used one. all shops i know of charge a minimum of $45/hour with a 1 hour minimum shop charge. i would bet you're looking at 1 hour plus the cost of new bearings - so probably $100 or more. you can get a used one cheaper than that shipped to your door. no down time, calling, asking around, dropping it off, etc.

 

the funny thing is that whether you install a new one or a used one i promise your next issue (if there is one) is with a ujoint, not the used (or new) carrier bearing.

[svxpert]

<<I manage a large municipal fleet shop and have access to a press, etc. Even though the service manual said the shaft wasn't servicable, I planned to give it a try.>>

 

 

how many miles on the car? since the driveshaft never (rarely) goes bad, my diagnosis over the internet is a bad wheel bearing replacement.

 

what kind of shop did you take it to? any idea how they did the wheel bearings? i have heard and seen horror stories with people replacing bearings at a shop that has no clue. they might have damaged the hub, in this case, every set of bearing that go in, go bad only after a short time.

 

also, check the gear lube in the rear and make sure its:

 

1. gear lube

2. clean, no water

3. filled to the top hole

[uniberp]

Maybe a very slight vibration, but not sure. I manage a large municipal fleet shop and have access to a press, etc. Even though the service manual said the shaft wasn't servicable, I planned to give it a try. Nipper thinks it may be the rear diff. I didn't hear any noise when I listened with a stethascope, but it's pretty hard to tell. My center bearing is shielded with a tin cover that I'll need to remove before checkin it out. Whatever it is, the noise inside the car is getting louder. Sooner or later something will break. Hope I figure it out before then. Thanks for the tips. I'll let everyone know what I found (when I figure it out!). Thanks again.

 

Phillip

 

The U-joints are staked in, and it appears the spline in the middle is swaged closed, although I didn't remove the rubber boot. I live in the midst of the Midwests largest collection of machine shops (west suburban Chicago) and I could NOT find a drive shaft shop to take the job on. I felt like very small change in the land of big diesel driveshafts.

[nipper]

Any shops that specialize in 4wd pickups or off road vehicals? They make custom driveshafts too.

 

nipper

[subyrally]

the problem is that subaru claims its not servicable, even though you can take out the castle nut holding it on and ter it down. the real problem comes when you try to get a replacement carrier for it. i took mine to a drive shaft shop not too long ago (gary should remember that) we went through multiple suppliers' catalogs and called a few, no one in the aftermarket produces a carrier in the right size, htere were a couple that were very close, maybe a little grinding and drilling here and there, but we couldnt find anythig that would just bolt in. and from what i remember from the dealership, any drive shafts they can get are $500, even for the old school cars since i believe they are interchangable. i think they just rounde3d em up into one part number, whn you look uip the old part, it comes up the same as the new one, at least at my local dealer.

 

 

good luck, and if you can find someone that can get the proper carrier bearing in the aftermarket, please let me know, ive been looking for a while now.