Thrumming noise: Drive shaft center bearing, or rear wheel bearing?

[J. M. van Swaay]

1994 E500 130K miles:

I have what can best be described as a thrumming sound coming from the back of the car. Sound frequency varies directly with speed and is present at all speeds. Sound is not affected by loading/unloading the drivetrain, and is also not affected by cornering. From this, I conclude that it is not a wheel bearing noise and it is also not a differential pinion bearing or axle shaft bearing noise. That leads me to believe I have a bad drive shaft center bearing. Anybody have any more diagnostic tips before I commit to replacing the center support drive shaft bearing?

Thanks,

J. M. van Swaay

 

[J. M. van Swaay]

Forgot to mention that I verified proper gear oil level in the differential. Gear oil has been changed during my ownership…

 

[gsxr]

J.M.,

If the driveshaft support has never been replaced, it would probably be a good idea to replace that (OE only!) along with the bearing (OE, or name brand aftermarket ok). Not a fun job, typically the entire exhaust has to be removed, and separating the resonator from the catalyst pipe without damaging either NLA component, can be a nightmare. VERY difficult without a lift. If the resonator/cat have been apart in the past 10 years or so this might not be a problem, but if untouched from 1994, plan on a fight. If you pay a shop to do the work, make sure they know to NOT damage either component because they can't be replaced. On a lift, you could remove the catalyst+resonator together. If you have factory catalysts, it's critical to not damage them... most aftermarket solutions are inferior, and/or cost a fortune.

I'd consider having the driveshaft assembly balanced before re-installing... if the flex discs are old or worn, consider replacing them as well (OEM SGF only). Driveshaft angles out of spec may also cause issues but this is difficult to measure and difficult to remedy.

Another long shot for the cause of the thrumming could be a worn axle/CV joint but I don't know how to conclusively diagnose this. @jhodg5ck ?? @Klink ?

 

[J. M. van Swaay]

Thanks for the reply! I removed the exhaust over 10 years ago when I did the B3 (reverse) clutch discs. I did have a lift in my garage then. When I reinstalled, I used plenty of anti seize, maybe that will now be rewarded??? I’ll have to check but I think I replaced the front flex disc as well. Question, Does the entire drive shaft have to be removed or can you replace the center bearing by just removing the back (or front) half? I do remember removing the center bearing support but I can’t remember if I had both halves of the drive shaft laying on the garage floor….

 

[gsxr]

Yes, you'll need to remove the entire driveshaft... the bearing is pressed on to the shaft, and the bearing is pressed into the carrier. It would be more difficult to attempt this with half the driveshaft still in the car. The hard part is removing the exhaust. Since you applied anti-seize to the exhaust fittings last time, they MIGHT come apart easily - smart move 10 years ago!

 

[J. M. van Swaay]

OK, it’s starting to come back to me now... I’m planning on replacing the whole bearing and support assembly assuming it’s still available. Is there a special tool required to pull the old assembly off of the shaft? (I have assorted gear pullers) Is the the bearing to shaft an “interference” fit or should it slide off without to much difficulty?

 

[195910]

Replace the centering bushings on both ends of the driveshaft, check the U-joint aswell.

 

[gsxr]

OK, it’s starting to come back to me now... I’m planning on replacing the whole bearing and support assembly assuming it’s still available. Is there a special tool required to pull the old assembly off of the shaft? (I have assorted gear pullers) Is the the bearing to shaft an “interference” fit or should it slide off without to much difficulty?

There is a special tool but it's just a long-jaw puller (photos below). The bearing isn't super tight on the shaft and is a pretty easy press fit into the rubber-lined carrier.

 

[J. M. van Swaay]

Thanks for all the tips! I’ll get some parts ordered then report back after I get this done. Probably won’t be till January or Februray.

J.

 

[r44raven]

Am I right in thinking that, despite there being alignment arrows on some of the shaft components to aid correct reconstruction, it's wise to make your own marks on each part before deconstruction, so there are no errors (which can lead to vibration) when rebuilding?

 

[gerryvz]

Yes, you should make your own markings before separating the pieces.

 

[J. M. van Swaay]

Finally getting back to addressing this after not driving the car for the last 6 months. After some additional diagnosis, I now believe my thrumming sound is coming from the left rear wheel bearing. After a lot of cornering and listening, there is a very slight correlation between the sound when loading/unloading during cornering. I have removed the half shaft, brake, and brake rotor so I can spin and feel the bearing. There is no play but it does feel dry whiny when spun by hand. I’m this far in so I plan to take a chance and replace the bearing. My local parts store has a 5 lb slide hammer (rental tool) which I plan to try first. Here’s a picture of where I am, just want to confirm there are no retainers or snap rings holding the bearing somewhere where I can’t see. I’m assuming I attach the slide hammer to the hub and give it a go. Is there anything I’m missing in my approach? Thanks.

 

[gsxr]

Finally getting back to addressing this after not driving the car for the last 6 months. After some additional diagnosis, I now believe my thrumming sound is coming from the left rear wheel bearing. After a lot of cornering and listening, there is a very slight correlation between the sound when loading/unloading during cornering. I have removed the half shaft, brake, and brake rotor so I can spin and feel the bearing. There is no play but it does feel dry whiny when spun by hand.

Yup - that's the typical failure mode, IME. Zero or near zero play, but it feels "rough". Should be perfectly smooth & silent. The annoying part is that you must remove the halfshaft to test this, which as I'm sure you learned, isn't fun.

I’m this far in so I plan to take a chance and replace the bearing. My local parts store has a 5 lb slide hammer (rental tool) which I plan to try first. Here’s a picture of where I am, just want to confirm there are no retainers or snap rings holding the bearing somewhere where I can’t see. I’m assuming I attach the slide hammer to the hub and give it a go. Is there anything I’m missing in my approach? Thanks.

You are correct, no retainers or snap rings. The hub is a press fit into the bearing, which has a split center race. The outer race will remain attached onto the hub and must be removed separately with a bearing splitter and hydraulic press (or equivalent means).

The hub may or may not pull out with a slide hammer. It takes a LOT of hammering. If it absolutely will not budge, you will be forced to use the proper rear wheel bearing removal kit like this one. Sadly it appears this is not on the list of AutoZone freebie loaner / rentals.

Once you have the hub pulled out, you still need the bearing R&R tool (available on eBay, made by Miller tools). Search the forum for details on this specific job, it's been covered pretty well in the past.

 

[J. M. van Swaay]

Thanks! I’ll give the slide hammer a try. If it doesn’t work I’ll buy the removal tool. (I already have the bearing R&R tool)

 

[J. M. van Swaay]

Here’s a link to a video with audio of the bearing being spun by hand. I don’t have much experience with this but that doesn’t sound good. Comments? Bearing video · Friday, Jul 4

 

[gsxr]

Here’s a link to a video with audio of the bearing being spun by hand. I don’t have much experience with this but that doesn’t sound good. Comments? Bearing video · Friday, Jul 4

Yep - sounds bad to me. Should be silent.

 

[J. M. van Swaay]

I win. About 25 minutes, 20 of which were removing the snap ring.

 

[J. M. van Swaay]

Now I have to figure out how to get the race off the hub…

 

[dreaming.haze]

@J. M. van Swaay - A bearing splitter will be your friend here: https://www.amazon.com/CTA-Tools-8065-Bearing-Separator/dp/B005OH0KTA - Another option is a dremel cut off tool to slowly dig into the race until it is weak enough to be removed with a screwdriver or similar.

Good job getting it out quickly though! They can put up a fight like Dave mentioned

 

[J. M. van Swaay]

The bearing kit I bought 7 years ago for the other side was a FAG number 129-980-04-16. This part shows no longer available. Is the SKF bearing kit acceptable? Just don’t want a cheap Chinese bearing….

 

[J. M. van Swaay]

Ordered the “optimal” kit (cheap) includes bolts for halfshaft. Ordered SKF also in case “optimal” is junk…..

 

[gsxr]

Some of the bearing "kits" include hardware that may or may not be the correct size (halfshaft bolts, 30mm outer nut, etc). SKF is usually good stuff.

 

[J. M. van Swaay]

Scored the race with a dremel cut off wheel as suggested. Gave it a good sledge hammer smack with a chisel and it snapped open and came right off. I’m 2 for 2 today, maybe I should go to Vegas…

 

[J. M. van Swaay]

Bearings arrived yesterday, not sure what I should use. The vendor substituted a Timkin for the SKF, the Timkin has “Korea” stamped on the side. The Optimal does not have a stamp that would indicate country of origin, but I did find on their website that Optimal bearings are made in Germany. the Optimal kit was about $50 and the Timkin was $100. Because the Optimal was cheap I have my doubts….. any suggestions?

 

[gsxr]

Timken makes good stuff. I would use the Timken bearing.

If Optimal is afraid to list COO, I'd avoid using it...

 

[Seangbadee]

J.M.,

If the driveshaft support has never been replaced, it would probably be a good idea to replace that (OE only!) along with the bearing (OE, or name brand aftermarket ok). Not a fun job, typically the entire exhaust has to be removed, and separating the resonator from the catalyst pipe without damaging either NLA component, can be a nightmare. VERY difficult without a lift. If the resonator/cat have been apart in the past 10 years or so this might not be a problem, but if untouched from 1994, plan on a fight. If you pay a shop to do the work, make sure they know to NOT damage either component because they can't be replaced. On a lift, you could remove the catalyst+resonator together. If you have factory catalysts, it's critical to not damage them... most aftermarket solutions are inferior, and/or cost a fortune.

I'd consider having the driveshaft assembly balanced before re-installing... if the flex discs are old or worn, consider replacing them as well (OEM SGF only). Driveshaft angles out of spec may also cause issues but this is difficult to measure and difficult to remedy.

Another long shot for the cause of the thrumming could be a worn axle/CV joint but I don't know how to conclusively diagnose this. @jhodg5ck ?? @Klink ?

I couldn’t agree more with @gsxr—when it comes to critical parts, sticking with OEM is the way to go. A couple of years ago, I replaced the part on my E320 using the SGF brand, and I’ve had zero issues since.

 

[disrupted]

 

[J. M. van Swaay]

Slipped the Timken bearing in this afternoon, reassembled everything and went for a drive. Thrumming noise is gone! This confirms problem was rear wheel bearing not drive shaft center bearing. Note to site administrators, maybe the title of this thread can be changed to reflect that. Maybe thread title should be “thrumming noise, drive shaft center bearing or rear wheel bearing?”

 

[doolar]

Some of the bearing "kits" include hardware that may or may not be the correct size (halfshaft bolts, 30mm outer nut, etc). SKF is usually good stuff.

SKF should be good. It’s a Swedish company founded in 1907 with a very high reputation.

The name SKF is an abbreviation of ”Svensk Kullager Fabrik”, which translates to ”Swedish Ballbearing Factory”. There were no need for fancy company names back then.

 

[lowman]

SKF should be good. It’s a Swedish company founded in 1907 with a very high reputation.

The name SKF is an abbreviation of ”Svensk Kullager Fabrik”, which translates to ”Swedish Ballbearing Factory”. There were no need for fancy company names back then.

It should be and usually was good ,but unfortunately SKF is far from what it was before. Most stuff of the reproduction is outsourced to chinese makers. Ive had personally poor experiences the last years with SKF products.Mostly timing belt kits,where the idler pulleys and such are NOT made by SKF.
I avoid SKF almost at all cost.

 

[doolar]

It should be and usually was good ,but unfortunately SKF is far from what it was before. Most stuff of the reproduction is outsourced to chinese makers. Ive had personally poor experiences the last years with SKF products.Mostly timing belt kits,where the idler pulleys and such are NOT made by SKF.
I avoid SKF almost at all cost.

Oh I was not aware of that, thank you for clarifying that! Although I only buy ball bearings from SKF. They’re often produced abroad like in France for example, but the quality has been good so far.

 

[lowman]

Oh I was not aware of that, thank you for clarifying that! Although I only buy ball bearings from SKF. They’re often produced abroad like in France for example, but the quality has been good so far.

I do think that if the ballbearing itself...says SKF on it,,,i would reckon it would be ok. But as far as many of the parts supplied by SKF as a timing belt kit,,,serepentine belt, waterpumps,,,etc...i would never get any of those at this point..unfortunatly..Cause i do have a softspot for SKF.Like you said..they have been a quality procuct for years and years...and its a shame that the name is getting tarnished by these days poor quality controll/manufacturing processes..