I am replacing the front brake rotors on my Group S Alfetta (116) and I am looking for the torque settings for the centre hub nut. Google provides a range of answers but I understand that I should tighten the nut to about 25ft/lb and then back it off 90 degrees before locking the castle washer in place with a split pin.
Could someone please let me know if I am right?
G'day Nigel, On the 105 tarmac rally cars we used to just tighten them up fairly firmly, tap the back of the upright to help settle the bearings then back off the nut until the washer could be easily moved with a screwdriver. Then feel for play at the wheel rim, which should be very slight to imperceptible. Much more important that there be NO preload on these bearings, unlike diff pinion bearings. Preload here shortens bearing life greatly, particularly that of the small outer bearing. (not sure if 116 has same bearings as 105).
However we have now moved to putting a spacer between the bearings and then tightening up to 100 ftlb or so. This has the double benefit of allowing hub removal and refit without adjustment, and strengthening and stiffening the whole assembly thus reducing pad knock back and reducing the possibility of stub axle failure. Of course spacer length has to be accurate so we make them about .008" short and add a shim washer or two to get zero preload when tight. Shims of the right diameters are available cheaply on ebay.
Thank you all. All done now, new brake rotors and pads (Ferodo DS3000). These seem quite hard to source in Australia, does anyone know of a good supplier?
Perhaps Competition Friction?