W123 rear wheel bearing - can't get it tight enough!

[blue70beetle]

Replacing a trashed wheel bearing on my '82 and I can't get the new bearing any tighter than about 0.025" end play. I can't apply enough torque to turn the nut any tighter. Has anyone run across this?

This is my first wheel bearing on one of these, so I don't know how much torque it should take to crush the ring and set the end play. Is it a ridiculous amount, or do I have a bad component in my bearing kit that's not allowing it to crush?

The car isn't at my house and I'm using a borrowed vehicle until I get it fixed. I'm returning my loaner tomorrow so I'm kind of under the gun. Contemplating just putting it together to make the 11-mile trip to my house.

[Diesel911]

Originally Posted by blue70beetle

Replacing a trashed wheel bearing on my '82 and I can't get the new bearing any tighter than about 0.025" end play. I can't apply enough torque to turn the nut any tighter. Has anyone run across this?

This is my first wheel bearing on one of these, so I don't know how much torque it should take to crush the ring and set the end play. Is it a ridiculous amount, or do I have a bad component in my bearing kit that's not allowing it to crush?

The car isn't at my house and I'm using a borrowed vehicle until I get it fixed. I'm returning my loaner tomorrow so I'm kind of under the gun. Contemplating just putting it together to make the 11-mile trip to my house.

I think it is a problem most People have had doing the Job. See the Links for details.
Long Cheater Bar on your Breaker Bar for more leverage. It is also one of those jobs that if you had a 3/4" Drive Breaker Bar I think would be slighly easier and a stronger less flexiable item to put a Pipe on to act as a Cheater Bar.
This is one of those jobs that could damage a cheap 1/2" Drive Breaker Bar.
It also needs excellent support to keep the Hub from moving.
Please note I have not done the Wheel Rear Wheel Bearings before but I have read many of the Threads.
I believe a few People have even used a Floor Jack under the Breaker Bar to tighten it and some have allowed the weight of the Vehicle to come down on the Breaker Bar to tighten it but read up on that for the Details.

There is also a device that is called a Torque Multiplyer that Might be rented at a Tool Rental Place but I have not read of anyone using that. Shops that work on Big Rig Diesel Trucks or Construction Equipment often have them.

DIY Repair Links
http://www.peachparts.com/shopforum/forumdisplay.php?f=82
http://www.peachparts.com/Wikka/DoItYourSelf

[Stretch]

The crush spacer / washer thing is a pain in the arse. These things exist not only on the rear wheel bearings but in differentials as well. To start a crush spacer /washer thing in my differential I needed to apply about 7 metric tons to get the bloody thing moving => I did that on a hydraulic press just by compressing - no turning of flimsy looking nuts

Once you get them to start deforming the nuts are easier to tighten - it is just climbing that first mountain - getting it to move. It sounds like your crush spacer / washer thing is still in its stubborn virgin state. This next suggestion is very risky - so use with caution - you might want to try to crush the bloody thing in a vice or something like that first and then install it. If you "pre" crush it too much however it might not even slide on the hub shaft again - and you need to make sure that you still have enough give in the crush thing so that there is enough tightness in the assembly so that the nut does not come loose.

[Zulfiqar]

Another technique is to use the slotted tool and hammer it in, use the breaker bar and rest it on the ground. Get two lug bolts that you will sacrifice and install on the hub then turn the hub with a strong rod with brute force.

[rscurtis]

If you can't make any progress, and the old spacer is OK, install it in place of the new one. Roller bearings are made to a standard dimension. If the end play was OK with the old bearings before they failed, it should be OK with the new bearings.

[SD Blue]

I just did the rear wheel bearings on the RH rear axle, earlier this week and had the same problem. The only thing that works is a longer bar to get the leverage. I tried a 48" breaker bar and could only get it to ~.25. Finally, I pulled the handle off of my Arcan floor jack and was able to get it within tolerances. The other tricky part is keeping the bar from slipping every time you applied torque.

When I decide to take on the LH side, I may find some real heavy flat stock that I can drill holes in and make a holding fixture that will permit slipping a floor jack handle over the end, or even clamping with heavy u-bolts. Something very similar to what is used in this video:

Setting pinion bearing preload on the Ford 8.8" axle - YouTube

[Skippy]

I used a 24" pry bar until I bent it. Then I used a 4 foot length of 2x4.

[winmutt]

I still wake up in the night sweating and panting having nightmares of this job. I dont even remember what I did but I do remember I went to far and despite the manual I did not start over. I want to say I used the floor jack trick. What a pain in the ass...

[blue70beetle]

Update: had another go at it last night and I got it! As others said, it just takes a ridiculous amount of effort to make it move. I wedged the pin socket / breaker bar in on the back side, against the trailing arm, and then I used a 3' wrecking bar across two lug bolts to get it started.

Getting it to yield initially was the hardest part, which is consistent with how I would expect steel to behave in a failure situation - it took an insane amount of torque to get it started, and only a ridiculous amount of torque to keep going once it had yielded. I went through an iterative process - turn the hub a few degrees, check end play - until I was down to about 0.002", maybe just a little under.

Thanks for the suggestions and advice...not a fun job, but I've done worse!

[Skippy]

Originally Posted by winmutt

I still wake up in the night sweating and panting having nightmares of this job. I dont even remember what I did but I do remember I went to far and despite the manual I did not start over. I want to say I used the floor jack trick. What a pain in the ass...

I too went too far and didn't start over. I didn't have another crush washer, and it took a month to get one. I had been driving the car the entire time with nothing going wrong, so I decided to let it be and see what happens. That was something like eight months ago and so far, so good.

[The Gears]

New Slot Nut Tool

With the tool bolted into the wheel nut real pressure can be applied and this is just one thing to forget about. It won't slip out and ruin the tool or nut.
I used a 2"x"x8' in two wheel bolts and the jack handle on a 3/4" ratchet.
All went well with a gauge mounted on the brake backing plate.

[Stretch]

Originally Posted by The Gears

New Slot Nut Tool

With the tool bolted into the wheel nut real pressure can be applied and this is just one thing to forget about. It won't slip out and ruin the tool or nut.
I used a 2"x"x8' in two wheel bolts and the jack handle on a 3/4" ratchet.
All went well with a gauge mounted on the brake backing plate.

With that tool were you able to apply a crushing force at the same time? In other words with a bit of twist of the slotted nut could you whoomph the crush washer spacer thing in a bit more?

If so I am surprised you managed to make any effect with such a thin bit of rod and such a thin washer



It is really neat idea though.

[Diesel911]

Originally Posted by Stretch

With that tool were you able to apply a crushing force at the same time? In other words with a bit of twist of the slotted nut could you whoomph the crush washer spacer thing in a bit more?

If so I am surprised you managed to make any effect with such a thin bit of rod and such a thin washer



It is really neat idea though.

No, I think the idea was to simply aid in holding the Pin Wrench/Socket in Place; keeping the Tabs in their grooves while you tighten it.

I would be possible to make a Tool that compresses the Crush Sleeve with the Slotted Nut removed.
The Toole would be similar to the Pin Wrench but would have as you said a longer threaded Rod in place of the fat central Pin with a thick Washer to go on the Hub Side and a suitable Nut.

I am not sure if that would make the Job easier but it would certainly take the strain off of the Stock Nut and outside Threads on the Hub.

The question would be if a 29mm (about 1.14 inches) threaded Rod could take the stress of squashing the Crush Sleeve without stripping.
I have some 1 inch fine threaded Rod and it has 14 or 16 threads per inch. It could be that the finer threads might make it easier to crush the Crush Sleeve.

If you decided to modify the existing Pin Wrench the Tabs would have to come off and there is a bugger in that the central alignment shaft is only pressed into the Pin Wrench. If it is so difficult to crush the Crush Sleeve Welding the shaft inside the Tool might not work and there is not a lot of meat to thread it as the 3/4" Drive Hole takes up space.

[Stretch]

Originally Posted by Diesel911

No, I think the idea was to simply aid in holding the Pin Wrench/Socket in Place; keeping the Tabs in their grooves while you tighten it.
...

Oh yes - I've often read that the copy versions of this tool need adjustment to fit and so I guess they could also pop out of position. I trumped up the 120 euros or so for the tool at the dealer (which if I remember correctly actually worked out to be about the same price as the knock off tool and postage at that time) and had no trouble with the fit or it popping out of place.

Originally Posted by Diesel911

...

I am not sure if that would make the Job easier but it would certainly take the strain off of the Stock Nut and outside Threads on the Hub.

The question would be if a 29mm (about 1.14 inches) threaded Rod could take the stress of squashing the Crush Sleeve without stripping.
I have some 1 inch fine threaded Rod and it has 14 or 16 threads per inch. It could be that the finer threads might make it easier to crush the Crush Sleeve.

...

I still haven't done the sums but I think a pretty thick rod would be needed to get any where near the 7 metric tons of needed force I recently measured to crush a crush washer spacer thing in a W201 differential.

If I were to replace another wheel bearing in a W123 / 115 / 116 / 126 trailing arm again I think I'd do it off of the car and use my hydraulic press to get that bugger distorted!

[Rocket99]

I just did one and found that with my hand only on the pin wrench to tighten the slotted nut, as soon as it wanted to snug, hand only ... the end play was zero.

So I backed it off a tad to the point of the right end play. Zero crush.

Period.

Last time I had to use my body weight on a 3/4 in. breaker bar 2 ft. long, don't recall if there was a cheater on it to get end play down to spec.

When I pulled the flange last time it took zero torque, truly bare handed easy. I thought whoever assembled it made a mistake. I do not think that any more. In previous times it took heaven and earth there was so much torque, to get it off.

The FSM says nothing about big torque, only end play.

That crush ring is 12mm in width. So that, plus bearing race width dimensions and distance between landings where bearing races are "home" .... thats the math as to whether you need to crush the ring.

Get a crush washer more than 12 mm, or variations in bearing outer race width dimensions then maybe need lots of force to crush that spacer.

This time, first go round I did crush that washer a bit, .3 mm or so , so I had to get a new one. The flange was so tight it didn't want to rotate at all .

Another thing I've never seen: the bearing kit from FAG contained a slotted nut that did not fit the fancy assenmacher pin wrench, too much distance between opposing flat spots. So I got one from Mercedes dealer and it too had the same problem though not as severely bad . I had to modify that pin socket just a bit to get it to fit. A message to FAG about that went unanswered. I'll have to modify the slotted nuts , I plan to grind those flat spots with an angle grinder using the edge of a metal cutting, ie very thin, wheel. Very slowly and gently.

The 12mm width crush ring I got to replace the one I crushed a bit was also from the mercedes dealer.

these mercedes dealerships now ship parts for 25% to 30% off list price. Those spring struts on wagons that replace the rear shock as part of the self leveling suspension are now $99 (used to be $340 list) due to both lost price reduction and the discount at the dealers below and others I've found. If you have time and patience it is significant savings.

https://mercedespartscenter.com/parts/?action=oePartSearch&siteid=215720&make=MERCEDES-BENZ&model=

https://www.benzpartsforless.com/partlocator/index.cfm?siteid=216423

https://www.getmercedesparts.com/oem-Mercedes-parts.html