Hub nut - why is it so tight?

[twr7cx]

Having just undone one of the hub nuts on my D2a to replace a ripped boot on the Ashcroft CV's. I was wondering why it is to tight.

The wheel is secured to the hub via five wheel nuts, and the hub is secured to the steering knuckle by four bolts, and the steering knuckle is secured to the differential by the upper and lower ball joint.

The driveshaft is secured to the hub by the hub nut, but the other end of the driveshaft is a loose slide fit into the diff centre. So why then is the hub nut so tight?

The driveshaft doesn't seem to be able to move anywhere at the diff centre end seems to only fit so far into the diff centre before stopping and the CV bell side can't fit through the hub. So what could happen if the vehicle was driven with a loose hub nut or even no hub nut fitted?

[PhilipA]

Probably the splines would wear out. See Defender axle caps posts.
Regards Philip A

[discorevy]

What would eventually happen is the flange on the axle would burn out the axle seal , also allowing torque reaction forces to eventually introduce chatter on the splines , resulting in , as Philip A has mentioned, splines wearing out

[bob10]

Each wheel hub consists of a hub flange pressed into a hub bearing. The hub flange is splined to accept the outboard end of the drive shaft, which is secured to the hub flange with a stake nut / hub nut,[ 490 Nm] The outer race of the hub bearing is bolted to the end of the axle casing. An ' O ' ring seals the joint between the outer race and the axle casing to prevent leakage of diff oil.


Now, my experience of replacing the 'O ' ring seal on my left rear axle. Got to the stage of tensioning the hub nut, my good friend the truckie next door had a torque multiplier which would have enabled me to get 490 Nm on my tension wrench, but he wasn't home, and I was too impatient to wait. Tightened the hell out of the nut, using a spanner & persuader, took the D2 for a drive, slowly, got to the nearest roundabout, crapped myself when the left rear wheel wobbled. Drove slowly home, waited for mate, grabbed the multiplier, tensioned to 490 Nm [ had a way to go. ] All good since.


So, at best, the oil seal will leak diff oil, at worst, the wheel will feel like it is falling off. I broke my rule of not taking short cuts. The hub nut holds it all together, it's also a sobering thought that, besides the 490 Nm , only a 'stake ' keeps the nut in position. I make a point of raising each wheel at service time, & before big trips, to check for movement [ wheel bearing or hub nut] Bob

[justinc]

Mostly it is just to prevent axle spline wear. You will notice a click when on and off the throttle if they come loose. There is no interaction at all with the wheel bearing .

Jc

[bob10]

Thanks for that. As I understand it, the outer face of the hub bearing is bolted to the end of the axle casing. The hub flange & hub bearing are pressed together, and together are known as the axle hub. The hub nut tensions the hub flange onto the axle spline, and is an essential part of the system. Am I correct in thinking this, if not, could you put me straight, Bob

[Geoff86RRC]

Having just undone one of the hub nuts on my D2a to replace a ripped boot on the Ashcroft CV's. I was wondering why it is to tight.

The wheel is secured to the hub via five wheel nuts, and the hub is secured to the steering knuckle by four bolts, and the steering knuckle is secured to the differential by the upper and lower ball joint.

The driveshaft is secured to the hub by the hub nut, but the other end of the driveshaft is a loose slide fit into the diff centre. So why then is the hub nut so tight?

The driveshaft doesn't seem to be able to move anywhere at the diff centre end seems to only fit so far into the diff centre before stopping and the CV bell side can't fit through the hub. So what could happen if the vehicle was driven with a loose hub nut or even no hub nut fitted?

490nm torque D2 rear hub nut no torque wrench


I don’t have a 490nm torque wrench and so did the following. I weigh 82kg which multiplied by 2.2 is 180pounds. At two feet this is 360foot pounds. At a factor of 1.35 this is 490nm. Simply adjust the distance for your weight. Mark the bar at the distance and gently step and bring full weight onto marked position. Do not shock load. I note the torque altered from 490nm to 340nm when loctite spec changed From 680 to 640. I used a different loctite but opted for the higher torque to be on the safe side. The pamphlet that came with the Timpken brand hub said 490nm. My mechanic questioned it and we googled it and decided to follow the pamphlet.
Comments or thoughts?

[Kaaaiju]

I used my Milwaukee gun and gave it some ugga dugga, done about 6 hubs and 100,000km and no be issues

[twr7cx]

I note the torque altered from 490nm to 340nm when loctite spec changed From 680 to 640.

Do you have any further details on this please?


I don't use Loctite on them. Too many stories of being unable to seperate the shafts from the hubs with it. I've also stopped staking the hubs nuts - I just put some bright nail polish lines to be able to monitor if there is any shift. So far, over many many years and kms the hub nuts torqued up to 490Nm without Loctite and without being staked have not moved at all.

[Geoff86RRC]

Do you have any further details on this please?


I don't use Loctite on them. Too many stories of being unable to seperate the shafts from the hubs with it. I've also stopped staking the hubs nuts - I just put some bright nail polish lines to be able to monitor if there is any shift. So far, over many many years and kms the hub nuts torqued up to 490Nm without Loctite and without being staked have not moved at all.

When I researched it I read it on a forum. Thought it was AULRO but was the uk one. Sorry it was Discovery 2 2004 TD5 Landmark rear hub nut torque | LandyZone - Land Rover Forum (https://www.landyzone.co.uk/land-rover/discovery-2-2004-td5-landmark-rear-hub-nut-torque.348751/)
anyway I went for 490 AND staked the nut but my loctite is another brand so I just hope for the best
cheers

[twr7cx]

When I researched it I read it on a forum. Thought it was AULRO but was the uk one. Sorry it was Discovery 2 2004 TD5 Landmark rear hub nut torque | LandyZone - Land Rover Forum (https://www.landyzone.co.uk/land-rover/discovery-2-2004-td5-landmark-rear-hub-nut-torque.348751/)
anyway I went for 490 AND staked the nut but my loctite is another brand so I just hope for the best
cheers

If you read that thread in it's entirety, or particularly, the last few posts, you'll find that the discussion around the 340Nm and the LR Tech Bulletin posted up is for the Range Rover vehicles. There's a number of part overlaps between them and the D2. The Tech Bulletin specifically says:


NOTE: The torque value given in the next step is increased over the value in the Workshop Manual.

10. Torque stake-nut to 340 Nm (250 lbf. ft.) and stake the nut.

Given that the Disco2 spec is 490 Nm, the new 340 Nm is clearly not an increase in torque value, but a decrease. The Range Rovers however had a lower torque spec, so this was increased up to 340 Nm. This doesn't apply to D2 vehicles.

[PhilipA]

Still 340Nm is still Grunt Grunt bloody tight. I have a torque multiplier but still the earth/car moved before it was at 420NM.

I have never seen a properly staked nut work loose. It is a mechanical stop. all I can think of is that someone tightened the nut onto grease, rust or dirt.
I do mine up with a Ryobi rattle gun which is 260Nm, rattle it for a while then use the torque multiplier.
Regards PhilipA

[twr7cx]

Still 340Nm is still Grunt Grunt bloody tight. I have a torque multiplier but still the earth/car moved before it was at 420NM.

I use a 3/4" torque wrench (think it goes up to 700Nm maximum) and haven't had any issue with achieving the torque setting. I do have a second person sit in the car with their foot on the brake pedal and I leave the handbrake on but put the automatic transmission into Neutral as I don't want the loading going onto the park pin.

[Geoff86RRC]

The
If you read that thread in it's entirety, or particularly, the last few posts, you'll find that the discussion around the 340Nm and the LR Tech Bulletin posted up is for the Range Rover vehicles. There's a number of part overlaps between them and the D2. The Tech Bulletin specifically says:



Given that the Disco2 spec is 490 Nm, the new 340 Nm is clearly not an increase in torque value, but a decrease. The Range Rovers however had a lower torque spec, so this was increased up to 340 Nm. This doesn't apply to D2 vehicles.

Yes thanks i will read the book better...thanks that’s cleared up nicely, I must confess I was googling on the iPhone at the workshop re all this so missed the nuances of the RR increase. So the hub brochure at 490nm was right. Re the staked nut, may I submit that a poorly torqued nut will allow slap and chatter even if the nut staking prevents movement, also, we were tightening at ambient 16c and a hot hub axle bearing etc at max temp say with heavy braking on a long descent or slow sand work using lots of TC may cause heat expansion and lead to chatter. Not sure but very happy it’s at 490 and staked vs the rattle gun torque suggested by workshop.

The point of my reply was to help others without the $2,000 3/4 torque wrench get to 490nm or thereabouts easily. Even the best YouTube I saw ( an Aussie) just guesstimated. Yes I have read the post below re no loctite no staking and tight enough is good enough but must admit to a tad of perfectionism.

Finally, I sleep soundly knowing all the amigos are back where they belong and my new continental contact tyres 235x70 16 now have the best chance of gripping in an emergency stop. I went for these mainly road tyres because I’m sick and tired of the more knobbly a/t tyres scalloping and howling etc. we don’t do enough mud work to need them. Most of our off road is on sand.

i tried an 80kph full emergency stop and the brake Wabco slabs tyres road combination resulted in a very short stop with a slight pull to the left.

Finally, the hub change was indicated by the amigos and a rear wheel sensor fault and oil leaking onto the brakes. Further investigation revealed oil between the two parts of the hub meaning inner bearing, not an o ring. At 338k I reasoned that’s enough. Emboldened by this I may renew the other hubs over time but at the very least will have a good look for oil leaks, and check for play etc. at about $400 per corner I will do it over time.

cheers and thanks for the aulro collegiality as always.

[twr7cx]

The point of my reply was to help others without the $2,000 3/4 torque wrench get to 490nm or thereabouts easily.

Incase your interested, the Teng Tools 3492AG-E1 3/4" torque wrench can often be found for around a quarter of that price...