W123 rear hub bearings servicing/longevity - PeachParts Mercedes-Benz Forum

Marcan82 · #1 10-17-2023, 10:31 AM

Hi all! Hope all is well wherever you are.

There is very little information in our forum regarding servicing of these bearings. Is that because it's a dreaded job to do? Does anyone have experience in doing this job and how often should it be done?

For some reason it's kinda plaguing me as I have no history of this ever being done. Car has 137K miles and no noise or other symptoms that would cause me concern.

Thanks!

Sugar Bear · #2 10-17-2023, 11:24 AM

I've never seen a service interval for them and yes they are difficult to replace. Fortunately they have a low failure rate. Unless you carry heavy loads frequently or travel long distances I'd leave them alone. Failing bearings usually give ample warning by making noise.

If the car is a long term keeper I would look for parts (4 bearings, crush collars, seals) to do the job now and keep them on hand as they're not super expensive and will get scarcer as time passes. If you do get parts in advance, store them well since bearings rust easily.

Also get ebrake shoes and hardware.

5cylinder · #3 10-17-2023, 07:34 PM

Quote:

Originally Posted by Sugar Bear

If the car is a long term keeper I would look for parts (4 bearings, crush collars, seals)...

What is arrowed?

Diesel911 · #4 10-17-2023, 11:56 AM

Quote:

Originally Posted by Marcan82

Hi all! Hope all is well wherever you are.

There is very little information in our forum regarding servicing of these bearings. Is that because it's a dreaded job to do? Does anyone have experience in doing this job and how often should it be done?

For some reason it's kinda plaguing me as I have no history of this ever being done. Car has 137K miles and no noise or other symptoms that would cause me concern.

Thanks!

The typical methods of someone doing it themselves ruins at least one of the bearings and the threads on the end of the spindle/hub are in an area with thin metal making them prone to damage if someone is not carful.

So you essentially do nothing till a bearing is no good.

If you want to know if an issue is pending, get a dial indicator and take the end play on the spindle/hub.

Replacing the rear wheel bearings on a W123, W126

The above thread is by dmorrison, he has a wiki on removing the rear hub/spindle. Do not follow his instructions on beating it out from the inside as that is what damages the threads or swells and distorts that end.

You don't want to damage the spindle/hub. Over 5 years ago they were $350 each new and that is when new ones were available.
Another issue is when you get the spindle/hub out the old inner bearing is pressed onto it. Some find getting it off without challenging.

For those who had bad rear bearings when they were available some recommended just to change out the whole rear control arm.
I had to do that on mine as a had an accident and cracked my rear trailing arm. So, I replaced it with a used one and have never had any bearing issues from it.

My experience with removing the spindle/hub from a rear control arm comes from stripping the parts off of the old control arm.

Alec300SD · #5 10-17-2023, 03:07 PM

For your reading pleasure, see the detailed writeup thread on 'Stormcloud' (a W116 300SD).
Essentially the same procedure as the rear wheel bearing replacement on a W123 or a W126.

W116 Rear suspension remediation - including rear wheel bearing replacement – Part 1

That rear suspension was harvested and transplanted to 'Desert Rose' after 'Stormclould' was struck by an uninsured hit-and-run driver.

vstech · #6 10-19-2023, 08:27 AM

Find a scrap car... recover the trailing arms and axles and store them somewhere...

Far easier than dealing with the bearings...

vstech · #7 10-19-2023, 08:27 AM

126 and 123 use same trailing arms.

Sugar Bear · #8 10-19-2023, 10:20 AM

Yes and #35, the crush collar. If possible and reasonable $$$ get at least 1 extra crush collar/sleeve. They are one way only and if crushed too much during assembly they must be replaced.

The previous posts suggesting to get used hubs and arms are good advice.

Alec300SD · #9 10-19-2023, 10:41 AM

Don't forget #44, the collar nut that has to be staked.
They are not always reusable after they are unstaked to remove them.

If available, get #53 which is the whole repair kit.
It was NLA when I did my rear wheel bearings.
NOS does show up from time to time, check online dealership parts departments, MB Classic Center, Ebay in US and other countries.

sandova · #10 11-05-2024, 01:21 AM

Rear hub bearings on the W123 are known to last a long time, often well over 100,000 miles if properly greased and not subjected to excessive stress. Since your car has 137K miles with no noise or other symptoms, you’re likely in the clear for now. Unlike front wheel hub bearings, which are generally easier to access and service, rear bearings are more robust and are often left until they show signs of wear (noise, play, or vibration).
Typically, rear hub bearings in these vehicles don’t have a recommended maintenance interval; they’re more of a “replace when needed” part. Many W123 owners report getting 200K+ miles out of the original rear bearings.

Diesel911 · #11 11-05-2024, 01:01 PM

My W123 has at least 250K on. The left side is the original and on the right side I cracked a trailing arm and replaced it with a used one. Both have been fine.

If you want to watch over your rear axle bearings get a dial indicator and when you do a brake job check the end play. If you see your end play progressively getting larger or it is out of speck it is time to change the bearings.

Generally removing the bearings with non-factory service tools damages the bearings. Also, you need to have something to press off the large outer bearing or get a small cutoff tool and cut through it. Additionally, you cannot put any pressure/force on the inner threaded end that the locking collar goes on as it is thin.