Mark7022 Posted August 1, 2016 Share Posted August 1, 2016 Hi all,I am currently, and slowly, rebuilding my 1500 spitfire.I have cleaned out the differential but forgot to take down, accurately, the number of turns the castellated nut came off....LOL...upon tightening, I think i may have over tightened it.......I have a replacement collapsible washer to hand.Questions.To what torque measurement should I tighten the castellated nut?Upon loosening, how can I buy, borrow, make a tool for measuring the pre-load?Can these measurements be taken with the inner axles in place?All help and advice would be most appreciated, once the head shaking and rolling of eyes has subsided.On a separate issue, how can I access the universal joint on the pro shaft? One end is encased and I am not too sure which way the thing pulls apart.Many thanksMark Quote Link to comment Share on other sites More sharing options...
Nick Jones Posted August 1, 2016 Share Posted August 1, 2016 Diffs with collapsible spacer should be fitted with a nyloc nut and would originally had a pressed metal "anti-tamper" cover over it. The nut itself does not have a specified torque as it is done up to the degree necessary to give the correct pre-load.If it's a castellated nut with a split pin and did not have a metal cover over the nut before you dismantled it then probably you have a solid spacer and shims fitted (perhaps because the diff has be rebuilt before) and the nut can just be torqued up and the split pin refitted. However, if the diff does "go tight" when you tighten this nut this would indicate that it does have a collapsible spacer and that it has been over compressed.When re-tensioning a previously used collapsible assembly, you need to consider that you are not dealing with new bearings. Part of the preload in the original spec is to allow for a settling and wearing-in period and if you re-tension to new levels. My previous "bush" approach has been to nip the nut up until any free-play in the bearing is just eliminated. IIRC the original preload measurement involves measuring the torque needed to turn the pinion shaft (not that hard to arrange) BUT that is with the pinion only in the casing and not in mesh with crown-wheel or with sideshafts fitted.You could just ship it off to Marcus for fettling.....Nick Quote Link to comment Share on other sites More sharing options...
RedRooster Posted August 1, 2016 Share Posted August 1, 2016 Cheapest 0-13 lbft torque wrench ever Quote Link to comment Share on other sites More sharing options...
Mark7022 Posted August 28, 2016 Author Share Posted August 28, 2016 Hi all,Finally managed to find time to take a closer look at the nut.It does not seem to be the 'nylock' type, but it is covered by the metal anti tamper cover, with no split pin.So next question is how, easily, do I test for the pre load without specialists tools.Many thanksMark Quote Link to comment Share on other sites More sharing options...
Pete Lewis Posted August 30, 2016 Share Posted August 30, 2016 the book pre load is set and checked with the crown wheel out.its not an as assembled pre load, yours is a collapsible spacer so mark the nut postion and refit to the same place, you could measure the pre load to turn the whole diff assy, and check to see if its the same on refitting the nut depends how far you want to stripdown. Quote Link to comment Share on other sites More sharing options...
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