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I’m changing my hub bearing in 2 days, I don’t have a torque wrench that specified weight, can I just hand tighten it then back it off 1/4 turn? I just don’t want any problems now or in the near future. Thank you
You talking front or rear hub? I think your referring to the bearing preload nut on the front spindle which has a pinch bolt to lock it in place? That arrangement is only on RWD W212s as 4matics have similar front and rear hub bearings (large double-row bearings with large axle nut).
Bearing play is set with a dial indicator... can be done by "feel" with experience, but often frowned upon.
4matic? Cause its totally different than non-4matic. Still not sure what exactly your trying to tighten and then back off in place of using a torque wrench...
Ya the locking nut , I’m replacing the front hub bearing and a few videos they showing it has to be a certain weight, not to tight not to loose…. Then I’m thinking to myself , the locking nut kinda the shape of a horseshoe, a socket won’t even go over a round area so ya it’s don’t make sense what Mercedes is saying when it comes to the locking nut
With all the cash you're saving by doing it yourself, don't you think that treating yourself to the proper tool (torque wrench) to do the job correctly the first time is a wise investment?
Buy the frikkin wrench already. Or do the job twice, buying the wrench after the first time fails.
Too loose and you wreck the bearing due to play.
Too tight and you wreck the bearing due to excessive preload.
The torque wrench has no place to put a socket around the lock nut, you know the shape, it’s mostly like a circular horseshoe, no place to put a socket … my brother has the torque wrench but what would you put for the attachment ? That’s what I’m saying
The torque wrench has no place to put a socket around the lock nut, you know the shape, it’s mostly like a circular horseshoe, no place to put a socket … my brother has the torque wrench but what would you put for the attachment ? That’s what I’m saying
Please post a photo. The W212 is a modern Mercedes and should use a standard hub nut.
That locking nut is SO easy to over-tightened, no need torque wrench. Dial gauge 0.01 mm resolution is what you need. The bearing play/clearance requested is 0.01 to 0.02mm .
See attached WIS
I have a better way to do it, better in the way of the force you can apply on the "bearing - play" , as such you can get 0.01 mm clearance with confidence and repeatability.
=====================================I hope this may help others when they want to do the same.
My car was only 24,000KM when I did the bearing play adjustment inspection, so its kinda “virgin” in terms of its bearing tightness.
I did the bearing adjustment because upon inspection it was 0.04mm, for right front wheel and a bit less for left front wheel. MB calls for 0.01 to 0.02mm play allowed.
The WIS for my car model is : AR33.20-P-0300SX Adjust wheel bearing play
The challenge I face is when doing the bering play adjustment is :
#9
Adjust wheel bearing play by turning (arrow) the clamping nut (9d) in stages while pushing and pulling the brake disk (6) firmly back and forth
Do not twist or tilt front wheel hub (5) during the measurement. Correct measurement is only possible by pulling and pushing parallel to the wheel axle.
While it is do-able to grab the rotor and do a parallel pull and push on it, on a virgin bearing like mine, it hurts my fingers big time .. LOL.
The dust cover to rotor clearance is tight and I don’t have much room for my fingers. The pull and push force I need to perform to get the play, its totally unpleasant on my fingers + nails
I understand why MB reccomended “Correct measurement is only possible by pulling and pushing PARALLEL to the wheel axle.”
If we look at the WIS and perform the push-pull, we know that at either 3 or 9 o’clock there will be the brake caliper, so one can’t use 3 and 9 o’clock as holding points and thus 12 and 6 o’clock it shall be then.
The WIS showed a a dial gauge base installed at 6 o’clock position.
And the dial gauge reading needle at the center shaft ( spindle ).
Since the play we are reading is based on the rotor movement vs static position of the center shaft,
it makes sense the WIS insisted that : “Correct measurement is only possible by pulling and pushing PARALLEL to the wheel axle.”
If one does not pull parallel and let say did a tilted pull at 6 o’clock and push down at 12 o’clock,
and because the dial gauge base is at 6 o’clock……… the distance of center shaft mid point to that dial gauge base mid point , will create amplified reading due to distance and angle of tilt. I think its called angular size.
Make power assist, by using extension. Distance is our friend. We need to create a true equal push-pull and not a tilted 1 sided pull and 1 sided push.
Place the dial gauge where it will be at 90 degrees, where your push-pull position on rotor is at 0 and 180 degrees ( 12 and 6 o’clock ).
Fine tune dial gauge magnetic base position and how the arms angles are and how true straight the dial needle touch the mid center of the spindle/center-shaft….
To a point where when you spin the rotor 15-20 degrees left and 15-20 degrees right from 12 o’clock, the dial gauge does not deflect or read any changes.
You will ask why total of 30 to 40 degrees spin movement of the rotor disc required ?
Well, when you exert a push-pull force on the rotor disc and the bearing being smooth, I guarantee that you will also produce some spin left/right…maybe 5 degrees to 10 degrees
So we do not want readings from the spin movement, we want to read only the bearing play.
If you think you can install the dial gauge so true zero and can spin the rotor disc 90 degrees left and 90 degrees right and NOT cause the dial gauge needle to even move 0.005 mm, beer to you.
This is my push-pull position
Pay attention to why I place the magnetic base at 90 degrees at that particular spot.
That 90 degrees spot is the spot with least effect from angular size or dial gauge reading amplified by the free play.
It share the same east-west axis with the dial gauge reading needle. Since I need to leverage push-pull at 0*/north and pull-push at 180*/south on those extensions/wrenches to
get easy freeplay value swinging on the dial gauge, that spot is kinda neutral, un-effected.
So push-pull and then PULL will get me the freeplay value. Push-pull and then PUSH gets me the baseline before freeplay.
What I did is equal to what MB WIS required as : “Correct measurement is only possible by pulling and pushing PARALLEL to the wheel axle.”
Without hurting my fingers and I can apply strong enough force to produce the true freeplay value.
My W212 front bearing is taper type and the grease is still thick, getting 0.01 mm movement need a decent strong force.
I need to use camera zoom for this work as my eyes is not so good anymore … LOL
Also parallax error can occur if we use torch and reading the dial needle not close up enough.
PREPARATION
01. Make sure the brake caliper is rested back into its piston and the pads are pushed away from rotor disc.
You don’t need special tools ( in my case ) like a caliper pusher, use big jaw pliers and a 1-2mm thick cable tie or equivalent plastic thickness.
Pinch the brake pads so that it moves away from the rotor. MB WIS does not mention this, but this one will hamper your push-pull action on the rotor if the brake pad is
not lifted up or float enough above the rotor.
Doing above still does not move the pad 100% away or float above the rotor, yet.
You need to push the pad itself using non damaging plasti, push-a-tool, this is where the cable tie comes handy.
On my front brake pads there are two areas I need to push to make a gap.
GREASE CAP / HUB COVER REMOVAL.
Please don’t use hammer on it.
Use a big slotted/minus screwdriver and a plier. Do a twist action with the plier help while pushing down on the screwdriver decently hard so that it won’t slip,
slowly at 12, 3, 6 and 9 o’clock. Don’t leave any tool mark if you can, let alone make it look abused I take pride in avoiding tool marks whenever I can.
Above plier is also what I use to pinch the brake pads away from the rotor.
Wanna hear what 0.04 mm of freeplay sounds like ?
Because I have the "power-assist" of the wheel size itself, I can "hear" what a 0.04mm bearing play sounds like, because not parallel push-pull I did,
but one but one side lift up and one side push down to generate simulation on how the bearing will experience real road force during cornering and bad roads yada yada.
This is one noise you probably can't hear while on the road due to other noises.
Now, on the choice of dial gauge arms.
If I may suggest, use the 2 simple arms version like what I use. It is the stiffest I can find and it will do you good when trying to read 0.01mm while you are actually “shaking” the magnetic base of the dial gauge.
The choosen one not having the fine adjustment mechanism is actually a good thing for this work scenario.
How to test dial gauge arm stifness ?
Easy, when you already set its position to where you want to measure, spin the reading ring to zero.
The stiffer the arms are, the easier for us to set to zero without the needle deflecting a lot.
The two other magnetic base arms of mine ( left and middle ones ), is more suitable for work at odd angles and when the magnetic base itself is stationed at a static position.
Good luck Donny.
Last edited by S-Prihadi; 01-05-2022 at 03:36 AM.
Reason: add info
when most other manufacturers I have seen use a bolt in hub that is piloted around to back of spindle and held in with 3-4 bolts and outboard side is hub for wheel and rotor to fit.
Although Surya is absolutely correct, I have adjusted these three times on my '92 190E, my '93 S500 and my '03 S500, all 2wd. after changing bearings,hand tighten nut with loosened lock nut until it creates drag on spindle which you will feel by rotating brake rotor.
Then back off until the drag goes away, usually 1/4 turn or less, then tighten. The spec is .01 mm to .02 mm. which is 3 thousandths of an inch.
Last edited by pierrejoliat; 01-05-2022 at 09:21 AM.
when most other manufacturers I have seen use a bolt in hub that is piloted around to back of spindle and held in with 3-4 bolts and outboard side is hub for wheel and rotor to fit.
As stated, that preload nut is not set by torque... its tightened or loosened while measuring play with a dial indicator or by "feel". The allen pinch bolt, I'm sure has a torque value... less important.
Update. What a total **** show that was… I went to take off the locking nut and as it turning the pixel was turning with it, after 2 hours of fighting with it I come to find the pixel was broke off inside the bearing, part of old bearing fused to the pixel, now I need passanger steering knuckle with pixel. Found knuckle with pixel and hub bearing all in 1 piece on eBay used of course for 215$. Then I’m selling the car, it’s been nothing but problems past 2 months. It’s got 91k miles I bought it for 9500$ I can probably get 15k for it. I’m done shelling money at this car
I literally happen out of nowhere, car was driving fine, no noise no nothing. Abs lights went one I pulled over, smelt very slight burning smell, got car towed, went to put on hub bearing yesterday and spindle was spinning with locking nut, it was moving very slightly in and out. Then locking nut and piece of spindle fell off, all the little oval ***** from bearing fell out, bearing still wouldn’t pull off, piece of the inside of the bearing somehow fused to spindle, I never seen anything like it. So now need passanger steering knuckle with spindle. Past month this car been money pit. Only 91k miles and I take car of it so idk, I bought it for 9500$ I’m fixing and selling. I can probably get 14k so it is what it is I guess I really don’t want to sell it, body mint, I changed all the belts and few others but it’s just one thing after another now unfortunately
01-04-2022, 02:26 AM
I take pride in avoiding tool marks whenever I can.
