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| JustFX Member Since: 10 Nov 2016 Location: Mendip Hills Posts: 190   
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Well I have taken my rear hub off to solve a leaky seal. Had some fun as I seem to have a hub that isn't covered in the HBoL and its Restoration Book as well. Ended up ordering more parts and they have now arrived but as it is currently rather chilled outside I have a question for the Torqueisti of the forum.
I have tube like spacer and a staked nut for the hub. Manual says do this up to 210Nm do I need to adjust the torque settings for the cold? I quick guess would be that the temp for assembly would be 20C +/-2C so as I am working at 8C would the temperature co-efficient mean that I need less torque otherwise when it warms up the hub will be over tightened.  |
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2nd Dec 2017 9:26am |
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| JustFX Member Since: 10 Nov 2016 Location: Mendip Hills Posts: 190
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True a good Torque wrench is +/-4% but I suspect mine is bordering on the BS standard of 6%.
I did a quick calculation and I think it adjusts by about 3um for the amount of steel involved. So its close. Btw its a y2k 110. I have a stub axle seal (not on drawings, and not in the sub axle section of websites), plus I had only 1 seal on the hub itself (at the rear) no front seal. Also had to search for a better gasket as the first batch were rather thin. |
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2nd Dec 2017 9:56am |
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| miker Member Since: 13 Sep 2015 Location: Surrey Posts: 1763 
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I think you're over thinking it! Standard torque will be fine.
When I replaced one side of my rear bearings, the replacement nut was damaged, so ended up reusing the original. Torqued up it was at exactly the same point as the original bearing |
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2nd Dec 2017 12:36pm |
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| zsd-puma Member Since: 09 Aug 2016 Location: Kent Posts: 2720 
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Agreed just do it to the normal torque. Do you think the factory is a strictly temperature controlled environment? Or the local dealer's workshop?
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2nd Dec 2017 2:26pm |
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| rallysteve Member Since: 10 Feb 2014 Location: Cumbria Posts: 2227 
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I would be more worried about the friction coefficient of the threads!
Just use the torque wrench setting as per the book. Torque wrenches are just best guess anyway. 02' 110 TD5 Double Cab Rebuild Thread |
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2nd Dec 2017 8:36pm |
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| agentmulder Member Since: 16 Apr 2016 Location: Outer Space Posts: 1324 
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Not sure the argument of comparing the thermal contraction to the average tolerance of a torque wrench is the best way to think about this.
The way I see it the 210Nm is to ensure that you get the outer bearing races nice and snug against the spacer and then some more 'friction' to ensure any movement in the stake wont undo that. (Interested to hear if that's reasonable thinking?) Next, the actual spacer is what determines the bearing load, and if it is cold when you install it, it will be smaller as you've calculated and the bearing will be under more load than it should be - but, that's assuming non of the other components haven't also themselves shrunk, so let's assume they have and it's fine (?) But now consider that in summer the race, spacer, stub axle and nut will be under great axial compression, and the outer races, rollers and inner races will be under greater radial compression (this assumes the stub axle/nut threads haven't deformed). Heat begets heat. Not great. However - I suspect it's been designed to make these issues a non-concern (3um aint much right?) - I guess if you really want you could warm the spacer and perhaps the grease first?  Solved the bowel problem, working on the consonants... |
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2nd Dec 2017 11:04pm |
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| Devon-Rover Member Since: 22 Jan 2015 Location: South Devon Posts: 916 
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This is getting all too technical for me..
 I mean 3 um could be life or death right 
I'll admit to being a luddite and in this situation going back to the twin nut for ease of setting and future adjustability. Whilst doing 60mph the defender might feel like the space shuttle trying to leave the atmosphere I don't think the build tolerances are the same. |
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3rd Dec 2017 7:48am |
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| JustFX Member Since: 10 Nov 2016 Location: Mendip Hills Posts: 190
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I went on a quick calculation for the torque but consider how much of a turn you put on a nut to change the torque by 20Nm. I knew I was over thinking it but considering it is the bit that holds the wheels on I feel its important to get it right.
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4th Dec 2017 7:44pm |
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| agentmulder Member Since: 16 Apr 2016 Location: Outer Space Posts: 1324
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Keep in mind also that the desired end result actually isn't the correct torque, it's the correct bolt tension (or resultant compression if the fastened assembly). You get this via torque, with depends a lot on the friction coefficient along the thread surfaces, which are as random as the parts are greasy...
It's an interesting mental exercise, but I'm not so sure it's worth trusting the results as the final word on the matter. Solved the bowel problem, working on the consonants... |
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4th Dec 2017 8:37pm |
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