Torque # for front axle nut?

[RSTX]

How much should I torque the front axle nut?

I finally got my new 12.3" rotors and 1.8T calipers on.

 

[Occams_Razor]

Bently has the spec.

I am at work so I don't have the number handy but you have to first torque the nut to some ridiculous number, (I guess to seat the axle/bearing), and then back off and retorque to a much lower number.

Whatever you do don't move the car, (Bentley says to not even put any weight on it

), without torquing down the nut!

 

[RSTX]

Thanks for the reply. I'll await the final torque specs.

 

[oldpoopie]

from the bently cd.
Tightening torque:

 

[RSTX]

Hmmm, so I can tighten it down to 148 ft/lbs, back it off 180*, then tighten 60* from there. I'll give it a try.

Thanks.

 

[swfwater@gmail.com]

tighten bearing axle nut

Hmmm, so I can tighten it down to 148 ft/lbs, back it off 180*, then tighten 60* from there. I'll give it a try.

Thanks.

Dont forget to tighten down 37ft lbs before turning 60 degrees. I found that 37 ft pounds takes you back 180 degrees. Then try to get that 60 degrees is more than 148 ft lbs. I think they use degrees because most torque wrenches max out at 148 ft lbs or 200 newton meters

 

[Lug_Nut]

Theres an important step missing from that e-bentley, and that's to rotate the wheel (and bearing) after the nut has been loosened 180 and before re-setting to 37 lb*ft.
THEN mark the nut to tighten 1/6 turn more beyond 37.

 

[HogWrangler]

I use a 1/2 impact gun set on about 120psi of air. Hammer down until it stops turning seems to work just fine

 

[jimquatmann]

Using an air hammer will ruin the wheel bearing.

 

[scurvy]

Using an air hammer will ruin the wheel bearing.

An air hammer might, but a pneumatic impact gun will not.

This nut is one of the tightest on the car and you would have a difficult time getting it too tight. Too loose and you will have problems!

 

[elroy]

Do it according to bently spec and itll be loose in a couple days. Just reef on it, cant damage the bearing.

 

[derek5120]

If you want to go through the trouble of doing your bearing again then crank that old nut down and distort the bearing races. If you want it done properly then torque a New hub nut to spec. The nyloc in the new nut will make sure you get the correct torque without backing off.

 

[Riflesmith]

Using an air hammer will ruin the wheel bearing.

No, it will not ruin the wheel bearing. The axle nut pins the inner race between the outer CV joint and the axle nut. Squeezing the inner race will not damage anything. If this method ruins wheel bearings, my cars and all others I have worked on remain unaware of it.

Rattle gun is the only method I have ever used. Never a problem with a bearing afterward.

 

[[486]]

Mine are (left) the bolt style, tightened until it was at about 100 ft/lb, then another 180 deg or so
(right) the 12pt nut, cranked it down tight same as the other 100ft/lb ish, +90 deg ish

All they do is push the inner races together on a set-preload angular contact ball bearing.
You'll strip the threads off the stub before you will be able to deform those bearing races. In the case of the bolt style, the bolts elongate loooooong before then.
Had to beat the bajeezus out of mine to get the old axles out of the hubs, so if anything that will be what wrecked the bearings if they do fail.

As an aside, I remember reading here that you need different hubs to use the bolt style outer CV joints. Mine seemed to fit just fine, but they were takeouts from a '13 jetta and a '10 tiguan.

 

[gatz]

Follow the torque spec people. Our dealer stripped & necked my axle and I only found it two years later when I was doing suspension work. The nut wasn't completely loose but it just kept spinning while trying to remove. In this situation it could have been a life threatening disaster and we got lucky. No wonder other brands use a cotter pin. We opted to replace the whole axle, but could have replaced just the CV joint.

 

[Blacktree]

from the bently cd.
Tightening torque:

Hmm... that's interesting. Apparently, the manual on CD differs from the printed manual. I have the printed manual, and it says this:

Tightening Torques

12-point nut for drive axle to wheel hub
-- 200 Nm (148 ft-lb)
-- loosen 1/2 turn (180*)
-- turn wheel 1/2 turn (180*)
-- then tighten to 50 Nm (37 ft-lb) plus 1/6 turn (60*)

Hex bolt for drive axle to wheel hub
-- 250 Nm (184 ft-lb) plus 1/4 turn (90*)
-- loosen 1/2 turn (180*)
-- turn wheel 1/2 turn (180*)
-- then tighten to 250 Nm (184 ft-lb) plus 1/4 turn (90*)

Note that when you turn the wheel, it's with the wheel installed on the car, and the car on the ground. So you're rolling the car forward or back, to make the wheel rotate 180 degrees.

Also note that the manual says to lubricate the 12-point nut, and the threads on the axle with oil, but the hex bolt should be installed dry. (this would explain the difference in torque specs) It also says to lube the splines on the axle with oil prior to assembly.

And obviously, you should pull the axle fully into the hub, and snug up the nut (or bolt) before starting the torque sequence.

 

[[486]]

could have been a life threatening disaster and we got lucky.

I say that every time I go to bed.

caliper bracket holds the hub in pretty well, it'll let you know that something's wrong and to pull over. Ignore the astoundingly horrible noises and well, darwin had a point.

(this would explain the difference in torque specs).

bolt is m16x1.5 nut is m20x1.5
bolt is stretched every use, nut is not

 

[Mykl8]

So I was upgrading my axles today and when it came to the torque for the 30mm 12 point nuts I got a little confused... The manual says this:
• Weight of vehicle must be on its wheels.
• Tighten new 12-point nut to 200 Nm (148 ft-Ib) and immediately
loosen Y2 turn (180°)
• Turn wheel Y2 turn (180°) (roll vehicle)
• Make a mark on nut point with line (arrow A).
• Make a second mark on the wheel hub (arrow B) two
nut points away from the first. (The distance between
each nut point on a 12-point nut is 30°)
• Tighten the axle nut until both marks line up.

After you loosen the nut 180 and rotate the wheel by driving forward there isn't a second torque spec... I had only printed the second page as below and this is the alternate torque procedure. Once I got inside and looked into it more I found the "proper" torque spec as follows:
• Weight of vehicle must be on its wheels.
• Tighten new 12-point nut to 200 Nm (148 ft-lb) and immediately
loosen 112 turn (180°)
• Turn wheel 112 turn (180°) (roll vehicle), then tighten to
50 Nm (37 ft-Ib) plus 1/6 turn (60°)

The main spec has a second torque value and I will be using this method tomorrow

The page I missed V

The page I printed V

PS: sorry for bringing back and old thread, just wanted to point out that some Bently versions might have errors. Pretty sure the second alternate method is missing a second torque value as using this method leaves the nut VERY loose.

 

[Blacktree]

bolt is m16x1.5 nut is m20x1.5
bolt is stretched every use, nut is not

The main purpose of the axle torque spec is to get the required amount of clamping force on the wheel bearing. Regardless of what type of fastener is used, the bearing still needs that clamping force to hold it together. The nut with lubricant has a lower torque spec, because less torque is needed to achieve the required clamping force on the wheel bearing. The bolt needs higher torque, because it's installed dry.

The fact that one is a big ole nut and the other is a stretch bolt doesn't matter much, as far as the wheel bearing is concerned. They're just two different ways to achieve the same goal. And that goal is X amount of clamping force on the wheel bearing.

 

[[486]]

The main purpose of the axle torque spec is to get the required amount of clamping force on the wheel bearing. Regardless of what type of fastener is used, the bearing still needs that clamping force to hold it together. The nut with lubricant has a lower torque spec, because less torque is needed to achieve the required clamping force on the wheel bearing. The bolt needs higher torque, because it's installed dry.

The fact that one is a big ole nut and the other is a stretch bolt doesn't matter much, as far as the wheel bearing is concerned. They're just two different ways to achieve the same goal. And that goal is X amount of clamping force on the wheel bearing.

16x1.5 bolt stretches at say, 26klbs of clamp load
20x1.5 stud on end of CV bell doesn't stretch until something like 45k lbs clamp load
meaning, they can do a TTY tightening procedure on the bolt, but not on the nut style

wouldn't want to anyways, as by the book you'd be replacing the CV bell every torquing

They tighten the bolt to something like 60% yield then 90 deg (which actually likely isn't enough to yield the bolt at only .75mm)
where the nut style is snugged up, then cranked down 1/6 turn, or .25mm axial stretch
point on that bit is that lubed or not doesn't matter, as it is going by angle rather than final torque

 

[baminem]

First, I tried to tighten the axle nut to 200nm, loosen 180 degrees, mark points A/B and tighten 60 degrees.) It didn't work for me, far too loose. Without torquing the nut to 37 ft/lb I couldn't get it tight using the alternative procedure in the Bently manual cd shown below.





This method worked for me.

1. I tightened the axle nut snugly while jacked up.
2. Lowered the vehicle to ground and torqued 12 point nut to 200nm (148ft/lb)
3. Immediately loosened nut 180 degrees.
4. roll wheel half a turn (180 degrees)-roll the vehicle.
5. Torque the nut to 50nm (37 ft/lb)
6. Mark point on nut and another point 2-points over on hub (60 degrees).
7. Tighten nut 60 degrees until marks align.

At this point it was really tight, unless I started jumping on my breaker bar I wouldn't be able to tighten it anymore. I recommend you mark the nut to make sure you make it the extra 60 degrees and then you can double check the marks in the future to make sure nothing has moved.

 

[joep1234]

I tried the Bentley method and had to replace both bearings 3 weeks later because there was so much play. Both tires were slapping like they were going to fall off. I used an impact wrench to tighten both nuts and 40k miles later, everything is still OK. I used NAPA nuts with the nylon insert. Just my experience. May fail tomorrow but lasted longer than before.

 

[Powder Hound]

Cotter pins and the attendant castle nuts are what are used where the wheel hub runs on tapered roller bearings.

In this setup, we have sealed bearings containing 2 races filled with balls and grease. This is a very different setup. In order to assemble the sealed bearing package, the inner races come in two halves. The tension delivered by the axle nut on the CV joint stub is what holds those inner bearing halves together.

Next time you replace a bearing, pull it all apart and take a good look at the inner race halves, then come back here and explain how much torque applied to the axle nut it will take to distort them. I really want to hear the story.

Cheers,

PH

 

[~TDIguy~]

I tried the Bentley method and had to replace both bearings 3 weeks later because there was so much play. Both tires were slapping like they were going to fall off. I used an impact wrench to tighten both nuts and 40k miles later, everything is still OK. I used NAPA nuts with the nylon insert. Just my experience. May fail tomorrow but lasted longer than before.

I had alot the same experience, i torqued the nut to spec and a week or two later i noticed something wasnt right so i checked the nut and sure enough it was loose and the wheel wobbled back and forth like the bearing was out. I tightened it down good and hard heedless of the torque specs and shes still going strong today 7k miles later! Idk maybe i got lucky or unlucky but that was my experience.

On a slightly different note i had a bad experience with a autozone wheel bearing on that thing. Put it in, torqued to spec, and two months later it went out. I was kicking myself cause it was one of those deals of needing a bearing right now and not having a source for a OEM or reputable part so i got it from Autozone. Anyway i didnt do that again. My wheel was moving i would guess a half inch at the outer edge two months later. It went from being quiet to a serious wobble in the space of a 30 mile evening shopping spree. Im now running a Napa bearing with much better success but if i was to do it again id try to plan ahead a bit and get one from ID parts, they have a real good discount the last time i checked!

 

[wonneber]

I had alot the same experience, i torqued the nut to spec and a week or two later i noticed something wasnt right so i checked the nut and sure enough it was loose and the wheel wobbled back and forth like the bearing was out.

Did you put a new nut on or reuse the old one?

 

[jokila]

I tried the Bentley method and had to replace both bearings 3 weeks later because there was so much play. Both tires were slapping like they were going to fall off. I used an impact wrench to tighten both nuts and 40k miles later, everything is still OK. I used NAPA nuts with the nylon insert. Just my experience. May fail tomorrow but lasted longer than before.

I've followed it to the tee on many vehicles and never had a problem. You must have missed something or your torque wrench is way off.