Torque values and anti-corrosion compounds...

[Gerard]

Hi again,

The book indicated most torque values are for dry, plated bolts. A
plated bolt has less friction than a unplated bolt and therefore less
torque needs to be applied to produce the same clamping force, or so it
says going by the work needed to overcome friction when turning the bolt
in. The warning is to not grease the hole the bolt goes into, but the
thread of the bolt. Otherwise you're most likely going to be fastening
the thing against all the grease in the hole instead of the thread and
the thing will come out in service.

Now according to this it means greasing compounds and anti-seize stuff
allows you to put less tightening torque on the bolt as you're putting
it in, but the thing will still hold as well (same clamping force). Also
says it prevents thread damage from repeat removal and refitting of dry
nuts.

I've not seen a lubed bolt on my Audi, but I've seen some rusted ones
and don't want this again. Hence concern about using anti-seize and
using the original dry, plated bolt torque. I'm using mostly galvanised
nuts, stainless steel nuts or high tensile steel bolts (the black
looking ones) to replace the old ones. Was just concerned about this 40%
reduction in applied tightening torque which seems an awful lot. :)

G.