New Wheel Bearings Bad?
 

Last week, I replaced my inner CV joints, inner/outer boots and wheel bearings. The parts came from Pelican. Now, with the new parts installed it seems like both new bearings are bad. It sounds like a 4x4 truck with mud tires going down the road and I have a nasty vibration which is worst between 70-80mph.

I know I did everything right, the only questionable thing could be the hub bolt torque (this is supposed to be about 350 lb.-ft, I had to guess by standing on a breaker bar), if anything I could have over-torqued these.

Has anyoe else had bad out-of-box bearings? And two, for that matter?

Have you had the alignment checked since having the work done?

BC.

Yes. I thought about that too, I had it realigned and re-balanced the rear tires for good measure as well. Its definitely a bearing sound, although if I jack up the car and grab the wheels there isnt any movement like you would usually see in cars with bad bearings.

You say "you know you did it right". I don't know that. Did you use the SIR bearing installer tool from Pelican? You pulled the bearing into the hub by the outer race, right? You pulled the flange into the bearing by the inner race, right? The axle threads were clean and the nut spun freely, right? You tightened the axle nut atleast somewhat before setting the car on the ground, and definitely before rolling, right? I hope the cv's were packed w/grease and the cv bolts properly torqued. Bonus points for schnorr washers or threadlocker - those bolts can back out, leaving you stranded.

I've installed rear bearings on 911, 914, and boxster, and even one out-of-the-box bad FAG bearing is, to me, incredible - despite the name.

I didn't use the tool from Pelican (to be honest, I didn't know it even existed until I did some searching about my issue). I used a generic bearing puller/installer, and a "slide-hammer" style puller to remove the hub. The bearing puller was used to reinstall the hub. The bearing was pulled in by the outer race, but hub may have also been pulled in against the outer bearing race, but it didnt seem to take too much force to press it. The axle splines were clean, nut went on freely and was torqued while the car was still on jackstands (got it as tight as possible, then set the parking brake to finish torquing). I did use loctite on the inner axle bolts, and these were brand new.

The Bentley manual says to tighten the drive axle nut with the car on the ground.
Is that not correct?

Are you sure you correctly reassembled the CV joints?

wheel bearings
 

what was the reason for changing the original ones?

i had a wheel that sounded like the bearing was on its way out, and with the car in the air and no load on the wheel it was determined that the noise was coming from the tires, put a new bearing in anyway and the noise was still there

350 lb-ft? i thought the boxster rear axle nuts went to 250?

Probability of a bad bearing out of the box - extremely low.

Probability of Two bad bearings out of the box - infinitesimally low.

Sorry, I'm gonna go with Operator Error on this one.

:cheers:

Where Are Bearings Made
 

They replacement bearing may have been an inferior product made in China or South America. I would have went with Porsche or German made one. Sorry, but when it comes to major parts I will go with Porsche, even if it costs more. :dance:

PS: Since you spun the wheel and heard no noise, why did you do it. A bad bearing does not go quite with a spinning wheel in the air. If ain't broke...don't fix it!!!

"but hub may have also been pulled in against the outer bearing race"

That will ruin the bearing, and unfortunately I'm speaking from experience having done the same thing. There is a plastic-like piece inside the bearing that holds the balls in position that won't tolerate much loading.

The bearings were bad to begin with, which is why I did this along with the inner CV joints and boots (inner boots were torn).

The replacement bearings are FAG brand, which is the OEM manufacturer for Porsche, and they are in fact German made. I think my problem is more than likely that I didnt pull the hub in using the inner races as mentioned. Not a very expensive lesson learned, but a time consuming one. Hopefully this thread helps out some fellow bearing changers! Cheers and thanks everyone for the replies. :)

Quick question...

I bought another set of bearings and the SIR tool, and I'll be changing the rears again tomorrow. To be absolutely sure I do it right this time, I wanted to check on two things.

First, these bearings aren't directional are they? The outer rim of one side is a larger groove.

Second, since they are sealed bearings, I don't need to pack any additional grease do i?

Thanks in advance,

page 42-14 bentley says install bearings with numbers facing toward the wheel hub.

The bearings come ready to install.

Here is a thread on the Pelican board. It's actually for older 911's, but the concepts are similar. The post explains how to build a bearing puller similar to sir tools for less than $20 at Home Depot or Lowes. I did mine (911) using the procedure. It was very simple. Hope this helps.

http://forums.pelicanparts.com/porsche-911-technical-forum/179300-rear-wheel-bearing-removal.html

I feel like a dumbass. Bought another set of bearings and the SIR tool, put in the new ones and it still made the same noise/vibration. I knew that I did it right this time (thought I did last time too, but...).

After all of that, it turned out to be my cheap wheel spacers causing the issue. I tried out a larger set to see if it was the problem, and voi-la, no more vibration. Time to spend some more cash for the right size ones.

glad you found the issue.