 | Home > Maintenance & Modifications > TDCi hub bearing end float - purple spacers ??? |
 
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| tuesdayfox Member Since: 23 Jun 2013 Location: Sydney,OZ Posts: 129  
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hahaha
yup I bought extra just in case I screw up. the gasket is made of paper and very east to be torn.... as for the oil seal, they are actually the GREASE seals in the hub and dirt cheap too! |
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17th Jun 2016 1:42am |
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| Merlin Member Since: 30 Oct 2010 Location: Newmarket Posts: 981 
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Quote "it's as simple as torqueing up the stake nut to 210Nm"
I'm a bit confused about this 210 Nm. Is this correct? The rest of the post says to tighten to eliminate end float. Perhaps someone could explain. Thanks, Merlin |
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17th Jun 2016 9:23am |
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| nickhodgson Member Since: 08 Dec 2009 Location: Zambia Posts: 174 
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Would this procedure below from the WSM (LRL0410ENG 3rd Edition from 2001) not imply that there is a preload on the bearings as the inner nut is being tightened to a torque. For there to be no preload or indeed some end float would the nut not have to be loose?
 Click image to enlarge 1995 300tdi Defender 90 P/UP 2011 Puma Defender 130 D/C 2000 300tdi Defender 110 P/UP 2015 Discovery 4 SDV6 HSE |
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17th Jun 2016 12:38pm |
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| blackwolf Member Since: 03 Nov 2009 Location: South West England Posts: 17327 
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Yup, I haven't seen that version of the WSM and that would indeed apply some static load on the bearings. It seems to me that this is trying to remove the need for any kind of experience and judgement from the assembly process, which is also quite likely why the change was made to fit spacers.
In fact, although it is pure supposition on my part, it is not outside the bounds of possibility that the unsatisfactoryness of the procedure you've quoted is the reason why LR started to fit spacers instead. I have long believed that the reason for the change to spacers was to de-skill the assembly process (and hence reduce the time and cost) and not for any sound engineering reason. We will, of course, never know. |
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17th Jun 2016 2:41pm |
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| Rickydodah Member Since: 14 Jul 2014 Location: East Sussex Posts: 1091 |
I've followed this procedure for Land Rover bearings and have never had a problem (yet) but have to say that it's the only time that I've introduced any preload to tapered bearings and seems counter intuitive to established engineering practices. I know some taper bearings are happy to run with a preload as some gearboxes on our machines had helical cut gears which would try and unmesh themselves and the slack was taken up by the bearings, mind you the EP oil they ran in was like pitch when cold so this may haved help.......still doesn't seem right though  I started with nothing and still have most of it left! |
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17th Jun 2016 6:15pm |
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| agentmulder Member Since: 16 Apr 2016 Location: Outer Space Posts: 1324 
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I get the impression those instructions omit a page load of description. Perhaps going along with the idea that you can't explain something simply, don't.
In my opinion step 13.5 (10Nm), has an implied 'and use your experience here'. Also at step 15 when you maybe should revisit the 'feel'. Yeah? Yet to do this, so what do I know... but parts are on order  Solved the bowel problem, working on the consonants... |
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18th Jun 2016 1:45am |
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| nickhodgson Member Since: 08 Dec 2009 Location: Zambia Posts: 174
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I agree comments about de-skilling the workforce. Old fashioned mechanics are out and cheaper fitters are in.......
But about preload on taper bearings....on transfer box intermediate bearings (opposing taper bearings) there used to be a crushable spacer and is now a fixed spacer. I actually fit the crushable spacer as I don't keep a range of fixed size spacers to select from. And then I do put a bit of preload onto the bearings as in this application my experience is that any clearance allowed will cause wear in the casing with the bearing whose inner race butts up against the aluminium casing hammering the casing when you take up drive and you get another clunk in the transfer box. Maybe I am doing it wrong but have not had any issues so far. Another application of taper bearings is in the diffs and even there I understood there should be a preload on the pinion and crown wheel bearings. 1995 300tdi Defender 90 P/UP 2011 Puma Defender 130 D/C 2000 300tdi Defender 110 P/UP 2015 Discovery 4 SDV6 HSE |
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20th Jun 2016 5:50am |
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| blackwolf Member Since: 03 Nov 2009 Location: South West England Posts: 17327
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There are situations where it is appropriate to pre-load taper roller bearings, but they are situations where the bearings carry significant axial (as opposed to radial) loads.
Since the transfer box uses helical-cut gears, there is always a significant axial load (if the gears were free to slide on their shafts they'd seperate the moment you put load on them - this is the reason why in very high power applications double-helical gears (V shaped teeth a bit like the tread of a tractor tyre) are used). Similarly in the diff, there is a significant axial component to the load on the pinion shaft (it will tend to screw itself in or out of engagement) and the crownwheel will be driven away from the pinion, again putting an axial load on the diff carrier bearings. So it does happen, but in all these cases the preloads are actually quite small, and the axial loads predictable and sginificant. Wheelbearings will undoubtedly be loaded axially (when cornering, for example) but it is certainly unusual to preload wheelbearings and not something I would normally expect to do. Remember also that the transfer boxes, diffs, etc., are also far better lubricated and can dissipate heat generated by friction much better than wheelbearings. Preload => friction => heat. |
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20th Jun 2016 8:52am |
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| nickhodgson Member Since: 08 Dec 2009 Location: Zambia Posts: 174
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Blackwolf - Understood. Thanks for that. 1995 300tdi Defender 90 P/UP
2011 Puma Defender 130 D/C 2000 300tdi Defender 110 P/UP 2015 Discovery 4 SDV6 HSE |
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20th Jun 2016 9:05am |
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| pannawonica Member Since: 21 Nov 2010 Location: Clackline Western Australia Posts: 568 
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Would I be right too assume that a small air cut off tool would be best to remove the stake nut? With the two nut system I would be able to go in and out to adjust clean and relube as required with only a new lock washer?
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20th Jun 2016 9:09am |
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| blackwolf Member Since: 03 Nov 2009 Location: South West England Posts: 17327
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I wouldn't use a cut-off tool myself because all the abrasive dust and metal fragments are going to end up in a place where you really don't want them. Generally I use a small cold chisel or a sacrificial screwdriver and some gently tapping thereof to 'lift' the staked part of the nut off the flat on the stub axle. Once it is roughly back to shape you can unscrew it and although it will be a bit stiff it will unscrew without damaging the stub axle.
With the two nut system you are correct - you can remove the nuts as often and as many times as you wish replacing only the tab washer. In fact, although perhaps not ideal, you can reuse the tab washer at least a couple of times since you only need to bend one 'flat' over when securing it, so you can simply use a different 'flat' next time. The two-nut system is really much more practical for the competent DIY maintainer. |
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20th Jun 2016 11:15am |
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| blackwolf Member Since: 03 Nov 2009 Location: South West England Posts: 17327
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Just reviewing this thread, and I see that this question was never answered. There are really two questions here, firstly what is the difference between two notionally identical bearings, and secondly why are the "newer" ones substantially more expensive. The only explanation I can suggest is that the later and more expensive bearings, STC4382, which are specified when the later stake-nut-and-spacer arrangement is used, are manufactured to different dimensional tolerances than the earlier and cheaper, RTC3429, bearings specified for the twin-nut system. With the two-nut system, the dimesions are relatively un-critical, since any variation in any dimension can be taken up with the adjustment. With the single nut system, every dimension is critical since it will affect the distance between the two bearing, and hence the thickness of spacer needed. Since there is not an infinite range of spacers, the bearings must be manufactured to extremely fine tolerances to ensure proper fit. The finer the manufacturing tolerance, the greater the cost of manufacture. It is of course the case that all taper roller bearings (in fact all bearings) are made to very fine tolerances, but this is the only explanation I can think of. |
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19th Jun 2017 2:47pm |
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