Front wheel rocking from 3 to 9 oclock

[The Mirror Man]

I changed both front wheel bearings yesterday with genuine MB parts. I tightened then up as per the videos on YT but the NS wheel has a very slight rock when worked with the hands at 3 and 9 o'clock. It's fine at 6 and 12. I've already popped the dust cap off and retentioned the bearing by tightening it hand tight and backing it off a touch but it's still the same.

Is this normal or is the cause in one of the ball joints?

 

[KennyN]

Sounds like one of the balljoints , possibly the track rod end one.

Get someone else to move the wheel whilst you have a feel for any play

Kenny

 

[Jonesy161]

I would also add ...steering rack play.

 

[saff]

Would agree also, 12-6 usually indicates wheel bearing and 3-9 steering related.

 

[GordonTarling]

Procedures vary, but doing it up hand tight and then slackening it off is not the right way to do it. It may require tightening to a specific torque and then backing off slightly, or tightening until some drag is felt and then backing off a certain amount. Find the correct procedure for your car, carry it out and then check again.

 

[st13phil]

^ This.

It's incredibly easy to create excessive preload on taper roller bearings or to set them with excessive clearance, both of which will result in premature failure.


Sent from my iPhone using Tapatalk

 

[Lyserman]

Some specs for the 211 front wheel bearing:

Bearing end float: .01 - .02 mm

Grease capacity: Hub cover 15g. Hub total 80g

Screw for clamp nut: 11Nm

 

[190]

While they are not hyper critical, taper roller bearings function better with a slight amount of pre-load but the problem is that pre-load is extremely difficult to measure accurately and probably impossible to measure where other sources of drag exists from for example the brake pads. I believe that is the reason the automotive industry generally specifies a very small amount of end float as at least it can be measured with a dial gauge.

MB provides a means of infinite adjustment compared to the more usual castellated nut approach only adjustable in steps. While I like the MB adjuster, the fact that step adjustment has worked for so long should tell you adjustment is perhaps not as critical as you might think.

 

[Stratman]

I always thought you adjusted taper bearings with a little slack so when they heat up and expand on the road they don't become over tight.

 

[190]

It's true that thermal expansion may account for some or all of the end place. It would have been more accurate for me to say that the optimum setting is slight pre-load at the operating temperature.

There are still some wheel bearing applications where cold pre-load is factory applied. I have personal experience where they got it wrong and applied quite excessive pre-load and it still didn't destroy the bearing although it would have shortened the bearing life. Fortunately it was caught very early at 6000 miles before any real harm was done. If that seems surprising consider the graph below provided by a bearing manufacturer and note that the band of optimum setting is approx. 0.002" wide either side of zero end play. That's 5 times more than the MB spec.

All of which is to say, in my limited experience the end play setting isn't critical to the 0.0004" that MB makes it out to be.

 

[The Mirror Man]

Well I tightened mine "hand tight" and backed off about "4 minutes on a clock dial": I don't know any other way of putting it.

Have I don't it in an acceptable way???

 

[Stratman]

Can you ask them what software update was applied, in case my car needs it too



For the humorously challenged, I know.

 

[190]

Well I tightened mine "hand tight" and backed off about "4 minutes on a clock dial": I don't know any other way of putting it.

Have I don't it in an acceptable way???

The book method will be to use a dial gauge to measure the end float.

In the absence of a gauge I would usually torque to a few ftbs to make sure the bearing is properly seated than back off and hand tighten to zero end float. To determine the correct end float setting you could measure the thread pitch and calculate what degree of rotation is equivalent to the .01mm to .02mm spec. It's a fine thread, from memory I would say 1mm pitch or less. If we assume worst case 1mm then the nut should be backed off between 3.6 and 7.2 degrees.

Again assuming worse case 1mm thread pitch, at 4 clock minutes you have backed off 24 Degrees which will produce .067 mm end float which might explain the excessive play.

Even if the thread pitch is less than 1mm you have still set the end play to at least double the maximum spec.

 

[The Mirror Man]

The book method will be to use a dial gauge to measure the end float.

In the absence of a gauge I would usually torque to a few ftbs to make sure the bearing is properly seated than back off and hand tighten to zero end float. To determine the correct end float setting you could measure the thread pitch and calculate what degree of rotation is equivalent to the .01mm to .02mm spec. It's a fine thread, from memory I would say 1mm pitch or less. If we assume worst case 1mm then the nut should be backed off between 3.6 and 7.2 degrees.

Again assuming worse case 1mm thread pitch, at 4 clock minutes you have backed off 24 Degrees which will produce .067 mm end float which might explain the excessive play.

Even if the thread pitch is less than 1mm you have still set the end play to at least double the maximum spec.

I think I understand whet you are driving at: 360 divided by 60 minutes on a clock face X 4 =24.
Therefore, I should retighten and back off only 1 or 2 minutes??????

 

[mmfkf]

Hi,
just another point of view, but if you are trying to eliminate the wheel bearing as the cause of the play tighten it to just give some preload, then check for movement at 3 & 9 if its still there you should have ruled out the bearing and be looking for the other cause
Re-adjust your wheel bearing as above then.

I have just had same movement and it was the lower outer ball joint, a Neilsen C clamp ball joint press used in situ to replace it and all good

Happy hunting for the cuase.