Front Axle Wheel Bearing Nut....

So I'm 2 years out from replacing my front wheel bearings.
Went in for an alignment today after all of my (unrelated) front end work.

Tech told me drivers wheel bearing was shot.
Got er home, jacked up, there was play.
Checked the torque... Definitely was not where it should be.
Got it torqued back down as much as I could with a breaker bar. The play went away, wheel bearing is all good. Passenger side was ok.

So my question. I know the proper torque technique is something like 142 ftlb, back it off half turn, roll the car, 37 ftlb, then tighten 60 more degrees. It's an absurd amount of torque at that 60* mark, my guess is somewhere around 225 ftlb or so. That's when you do it initially.

Well these couple years of driving have either properly seated the bearing or the nut slightly backed off. Does anyone have a torque value there's been used in this situation? I've read the threads that it's "over 200" or "hit it with my 250 ft lb impact" but I'm wondering if anyone knows what that 60* translates to in torque value. I ask because I'd like to properly seat both of them again and I'll have access to a torque multiplier.

I suppose I could do the torque procedure from scratch again, but if I could just torque from where they are at that would be nice since I've already done the "rolling" phase. If not, will doing the procedure over again yield the same clamping force or do I need to go 65-70* after the 37 ftlb?

If you're performing that procedure that's in the Bentley manual again, then you need to get a new axle nut. It's a torque to yield (TTY) bolt, and once you take it off, you have to replace it. TTY means that you're tightening it to the point where you're at the yield strength of the bolt, and if you reuse it, the bolt itself is not as strong as it once was. I'd do this ASAP as you're running with an axle nut that might come off.

I used to just crank them down with my air impact and never had an issue. Now that I use a cordless Milwaukee - I have to be careful not to over torque it. It's a beast.

FYI - from what I remember, there was a mistake in the early procedures that left it under torqued. Also - 2 different specs depending on whether you have the 6pt or 12pt.

It is really difficult to over torque that nut. The axle stub is quite stout, and the bearing MUST be clamped together. If yours was loose, then if not now then in the near future you will be replacing it. The noise will be an increasing growling or howling that might change in loudness and tone with varying speeds and turning conditions, but it won't go away and will only increase in annoyance. Having the bearing even a little tiny bit loose will warp or peen the races in an incorrect position and set up the bearing for impending disaster, even if the tightened bearing appears to be back together in a workable state.

For myself, I torque it as prescribed, drive it for about 100 meters, then stand on the end of a 4 foot 3/4" breaker bar. I weigh well over 200# (as much as I'll admit to in a public forum) and they don't come loose again.

If you have any question, then get a new axle nut. They aren't horribly expensive and give peace of mind.

Cheers,

PH

Powder Hound said:

It is really difficult to over torque that nut.

Click to expand...

The Milwaukee I use does 700 ft-lbs tightening, 1100 loosening. I bet I could strip the threads off.

I will say this i never had a growling or grinding. I know mine go bad when I start to get a clunking noise on deceleration.

So it really sounds like no one knows what they've torqued them to beyond just the Bentley procedure and 60* after. No worries though.
I think I'm just going to bump it up to around 225-250 ft-lb and call it a day and keep an eye on them. When I get new tires installed I'll check the bearing to see if it's still solid and if it is, I'll get a new set of nuts and do the procedure over again.

jlav0330 said:

If you're performing that procedure that's in the Bentley manual again, then you need to get a new axle nut. It's a torque to yield (TTY) bolt, and once you take it off, you have to replace it. TTY means that you're tightening it to the point where you're at the yield strength of the bolt, and if you reuse it, the bolt itself is not as strong as it once was. I'd do this ASAP as you're running with an axle nut that might come off.

Click to expand...

I know what a TTY bolt/nut is thank you...I did not lose all clamping force. I will not be removing these nuts, unless I decide to do the torquing procedure over again.

Powder Hound said:

It is really difficult to over torque that nut. The axle stub is quite stout, and the bearing MUST be clamped together. If yours was loose, then if not now then in the near future you will be replacing it. The noise will be an increasing growling or howling that might change in loudness and tone with varying speeds and turning conditions, but it won't go away and will only increase in annoyance. Having the bearing even a little tiny bit loose will warp or peen the races in an incorrect position and set up the bearing for impending disaster, even if the tightened bearing appears to be back together in a workable state.

For myself, I torque it as prescribed, drive it for about 100 meters, then stand on the end of a 4 foot 3/4" breaker bar. I weigh well over 200# (as much as I'll admit to in a public forum) and they don't come loose again.

If you have any question, then get a new axle nut. They aren't horribly expensive and give peace of mind.

Cheers,

PH

Click to expand...

Dang you probably have easily 600 ft-lb of force on those nuts lol (including losses with flex and unknown factors). I guess I'm not too worried if I bump it up to 225-250.



The bearing was not completely clamped. The play that I was feeling was not wear play in the bearing. FWIW, it was not loose, it just wasn't torqued down like the passenger was, it was obvious that the bearing seated itself beyond the standard procedure in the Bentley.


I think I may have even replaced these bearings 3 years ago...I will have to go back and check my work log. It's hard to tell how long it's been like this. There have been no "worn bearing" symptoms at all since I replaced them. I understand the howl/groan/clicking when a bearing is failing is that's how I diagnosed and replaced the original ones a few years back.


I'll keep an eye and ear to the ground though and replace again if I start to feel these symptoms are coming back.

gforce1108 said:

The Milwaukee I use does 700 ft-lbs tightening, 1100 loosening. I bet I could strip the threads off.

Click to expand...

I have the same electric Milwaukee impact as you. It is a beast. You won't strip the threads off the axle shaft as it's hardened steel (very high Rockwell) but I bet you could strip the threads of the nut with it if you're not careful, or at least deform them beyond useability.


You mentioned that the torquing procedure was revised? Is there a link anywhere to this? I have the 12 pt and I followed my manual originally.


If I go the new nut route, I'll look at the revised procedure

KrashDH said:

So it really sounds like no one knows what they've torqued them to beyond just the Bentley procedure and 60* after. No worries though.
I think I'm just going to bump it up to around 225-250 ft-lb and call it a day and keep an eye on them. When I get new tires installed I'll check the bearing to see if it's still solid and if it is, I'll get a new set of nuts and do the procedure over again.
I know what a TTY bolt/nut is thank you...I did not lose all clamping force. I will not be removing these nuts, unless I decide to do the torquing procedure over again.
Dang you probably have easily 600 ft-lb of force on those nuts lol (including losses with flex and unknown factors). I guess I'm not too worried if I bump it up to 225-250.
The bearing was not completely clamped. The play that I was feeling was not wear play in the bearing. FWIW, it was not loose, it just wasn't torqued down like the passenger was, it was obvious that the bearing seated itself beyond the standard procedure in the Bentley.
I think I may have even replaced these bearings 3 years ago...I will have to go back and check my work log. It's hard to tell how long it's been like this. There have been no "worn bearing" symptoms at all since I replaced them. I understand the howl/groan/clicking when a bearing is failing is that's how I diagnosed and replaced the original ones a few years back.
I'll keep an eye and ear to the ground though and replace again if I start to feel these symptoms are coming back.
I have the same electric Milwaukee impact as you. It is a beast. You won't strip the threads off the axle shaft as it's hardened steel (very high Rockwell) but I bet you could strip the threads of the nut with it if you're not careful, or at least deform them beyond useability.
You mentioned that the torquing procedure was revised? Is there a link anywhere to this? I have the 12 pt and I followed my manual originally.
If I go the new nut route, I'll look at the revised procedure

Click to expand...

Yeah - I'd be worried about the nut more as well... I did a mini cooper recently and gave it a quick hit with the gun and found it way over spec. Now I just use it to loosen stuff and only snug stuff back up.
Looks like the procedure mentioned is correct. The original was missing the need to rotate the wheel between backing off 1/2 and retorquing to 37.
I did look into the 2 different spec I had in my head - looks likes that is for the 12 pt nut vs the 6 pt bolt style axles used on different models.

gforce1108 said:

Yeah - I'd be worried about the nut more as well... I did a mini cooper recently and gave it a quick hit with the gun and found it way over spec. Now I just use it to loosen stuff and only snug stuff back up.
Looks like the procedure mentioned is correct. The original was missing the need to rotate the wheel between backing off 1/2 and retorquing to 37.
I did look into the 2 different spec I had in my head - looks likes that is for the 12 pt nut vs the 6 pt bolt style axles used on different models.

Click to expand...

Yeah I'm even skeptical to break stuff free in certain situations. I use it the same way though, rapidly break stuff free and snug stuff, but never to final spec.



I just did my entire front end components and that front control arm nut that's tack welded in the subframe always scares me. I would never use a gun on that thing. Should never have to worry about it again though, I use a liberal amount of marine grease. The old bolt came out with ease.


Gutentight it is then for this one!

I don't weigh enough to get a nut that big that tight. 150 lbs roll back and forth back it off torque it and go for a ride. Check it again once you get back and its gotten hot.
The 12 point nuts are tight and self locking with a teflon lock ring on the end..
If you never reach yield strength there should be no worry other than it maintaining torque and that can be reset multiple times through the years.

Others might disagree, however, experience is what it is with this and other manufacturers makes and models.

Torque specifications are in foot pounds or length times force. So if you use a 6 foot lever you only need to exert 25 pounds of force. (measured at the end of the lever)

BobnOH said:

Torque specifications are in foot pounds or length times force. So if you use a 6 foot lever you only need to exert 25 pounds of force. (measured at the end of the lever)

Click to expand...

Per the Bentley manual though your initial torque would be that, then you would go drive it around, back it off 1/2 turn (?) then 37 ft-lb + 60*. That final step GREATLY exceeds 150 ft-lb of straight torque.


Basically what I ended up doing was using the passenger side nut as a gauge since it was still at the correct torque. With the torque multiplier I started at 50 ft-lb on the torque wrench (note that this was a 4x multiplier, so 200 ft-lb applied) and bumped it in 2 ft-lb increments until I was able to budge the nut a small amount when the wrench clicked. It ended up budging at 60 ft-lb (240 ft-lb applied). So that's what I torqued the driver side nut back to.


All seems well for the time being.


Unfortunately, the car is down again and I had to have it towed home this morning.

I just air impact them and never have problems.

The new Milwaukee's are good for 1400 ft-lb on loosen direction...did not bother to look at the tighten. Going to get one, and the drill and the small hex impact this weekend I hope.
cheers,
Douglas

PakProtector said:

The new Milwaukee's are good for 1400 ft-lb on loosen direction...did not bother to look at the tighten. Going to get one, and the drill and the small hex impact this weekend I hope.
cheers,
Douglas

Click to expand...

Enjoy, the thing is a tank!

Question- Did you simply tighten the axle nut on the loose bearing?

BobnOH said:

Question- Did you simply tighten the axle nut on the loose bearing?

Click to expand...

Yes I did. It was only 1


Going to keep an eye on it and whenever I have that wheel up in the air I'll check for play.


But even after 2-3 years of driving on the unit (likely with some of that after it settled MORE) the unit bearing is still tight with no play in the actual bearing interface.

I've never replaced those nuts. Never liked the look of the replacements compared to the originals.

Never heard of a torque to yield nut. It's bolts that are torque to yield...as in the length, not the threads.

I've wondered why they want those buggers so tight. Once the inner races touch, they touch. More tension on the spindle keeps it from flexing???

KLXD said:

I've never replaced those nuts. Never liked the look of the replacements compared to the originals.

Never heard of a torque to yield nut. It's bolts that are torque to yield...as in the length, not the threads.

I've wondered why they want those buggers so tight. Once the inner races touch, they touch. More tension on the spindle keeps it from flexing???

Click to expand...

You need more clamping force than just to seat the bearing and "hold" it in place.

I'm sure it has to do with clamping force needed based on shock loading and vibration profiles. Plus the moments on that spindle-bearing interface opposes the clamping force to basically "unload" the preload, like a gigantic spring.
All these factors plus a baked in safety factor, doesn't surprise me it's that high