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Hot Drive Shaft at Center Bearing

moustacio

New member
Joined
Mar 10, 2012
Location
Colorado
Hello everyone,

1988 745 turbo, m46 trans, and Type 3 two piece driveshaft.

While trying to get rid of vibrations by shimming the center bearing and carrier up and down I noticed that the driveshaft is very hot right at the center bearing. Also, just started to hear a scratchy whine from under the car. Bearing seemed to spin freely right before I started to hear the whine.

Is it normal for the Drive shaft to be hot right where the center bearing is pressed on?

Towards the trans it's not hot, and the u joint and second piece of the driveshaft is not hot. Also, new FAG center bearing and FEBI carrier were replaced around two years ago.

Thanks for any help
 
Not sure if it's normal for it to be hot TBH, but how does the bearing look/feel?

In a perfect world, I would blindly assume that it being hot is indicative of a cooked bearing and would look to replace it honestly.
 
Hi and thank you for the help,

I'm about to go out and check the center bearing before work. I'll let y'all know what I find.

Dl242gt: I used Lucas xtra heavy duty grease on the splines. I couldn't find any info on if it's a moly grease or not. Would using an incorrect grease cause the higher temperature?

Thanks agian
 
Any fresh grease on the splines is good. It's supposed to be a high temp moly grease like what is used for front disc brake wheel bearings or cv joints. You'll be ok if it isn't. I'm just saying what is optimal.
 
Thank you, I appreciate the help.

I just dropped the driveshaft after spinning the crunchy sounding center bearing. I believe the bearing is shot as there is some play as well. But maybe just the rubber mount got cocked.

Does anyone know of a way to remove the rubber carrier from the bearing without destroying it?

I'll do some searching on the web but thought I would ask as I don't remember seeing a procedure while researching.
 
Hi and thank you,

Looks like the car will be out of commission for a while. I may go for the genuine bearing this time. That is unless FAG bearings are of good quality and I installed it incorrectly causing a short life.

Thanks again
 
A question about installation if y'all don't mind:

I thought I've read to preload the carrier and center bearing. There are elongated holes on the mounting plate. Does anyone know which way and how far to install the carrier bearing mount to the crossmember it attaches to.

Upon removing the carrier and bearing it seems as though the bearing got cocked at an angle inside of the carrier. The bearing also has in and out play from the inside to outside races. Don't know if this is normal, the result of pulling on the outside race to remove from the driveshaft, or failure of the bearing.

Thank you for any additional help
 
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That bearing is toast. These are sealed cage bearings. Any play like you describe is bad and should be replaced. That said you do ruin the bearing when you pull it off unless you have a puller with thin enough jaws to get to the inner bearing race. That would be ideal but the bearing isn't usually that tough to get off by just pulling on the outer part.

No preload that I remember. Maybe someone here can clarify that has done one more recently. The slots are there so you have some adjustment when attaching to the body of the car. When you assemble the carrier you are going to put the bearing on the front driveshaft section. Then install the rubber carrier. Then you put the plate onto the bottom of the rubber carrier leave the bolts a bit loose. Now you have adjustment when putting the plate on the body to tighten those bolts under the carrier. Don't forget to grease the splines with some high temp grease. Hope that helps.
 
Very helpful yes, thank you.

I'm waiting on a stalled order to get my car back on the road. Went with the genuine bearing and I'll get some moly grease as well. Thanks for the heads up on that, I try to go by the book when possible.

I'll let y'all know how it goes when my parts find there way

Maybe I read your post incorrectly but on the 740 (940 too?) I don't believe you can install the bearing onto the driveshaft without first installing the bearing into the rubber carrier.

Thanks again
 
You're welcome. It's been awhile since I've done one on a 700/900. I never see them on the road around here. 89740turbos car is the first one I've seen in years. On the 240 you press the bearing on and then push the rubber carrier over the bearing.
 
I'm not trying to derail this thread, but it covers a topic I've been reading up on, and since it's a newer thread, I'm not bringing up the dead.

I had similar symptoms driving from Minnesota to Chicago yesterday. The water bottle I had sitting in the cubby in the center console was oddly warm, and I had a few instances of smelling burned rubber while going down the road.

I figure I may preemptively replace the ujoints while I have the drive shaft out, I have a fairly noticeable clunk when shifting from drive to reverse. Is there a brand of ujoints that's better than the others? I was thinking about going with GKN replacements.
 
Should be fine with GKN. Just be sure to get the correct size. Usually the rear one is the most worn ujoint but check all of them and the rubber quibo if your car has one.
 
Should be fine with GKN. Just be sure to get the correct size. Usually the rear one is the most worn ujoint but check all of them and the rubber quibo if your car has one.

Perfect, thank you for the quick response.

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Is that the rubber quibo?
 
Ah, thank you. Were those a manual or automatic specific application, or only certain years kind of thing?
 
Manual M47 in 240 and both M46 and M47 in 700 series. I think the M46 in the 700 series used it from 1988 and newer.

I always spell that wrong. lol. giubo
 
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