Diff pinion bearing preload torque spec?

[alpinewhite318i]

I installed a new outer pinion bearing and seal on my small case 3.91 LSD diff and tightened the nut to the previous marks that I had made. Right now the friction torque is maybe 5-7 inches when I measure it with the beam style torque wrench. Is there a default range I should be using for the torque rating? I see the metric mechanic site is using 14 to 16 inch pounds?

[TobyB]

There are 2 specs- one for new bearings, and one for used.

I forget both. But the mm number seems right for a smallcase new bearings.
The used bearing number was less- maybe 7-10? I forget. I found it
in the E21 service manual. Which is... err... I forget where that is...

If it was mine, I would tighten it to 10 inch-lbs of drag, run it for a while, and recheck.
What I found, seat- of- the- pants, is that for whatever reason, sometimes with new
bearings they could loosen more than I'd expect. Usually not a lot (10 degrees of
the nut, or not enough to lose all preload) but I did have one get loose enough to where
it clicked if you wiggled it. Caused all sorts of driveshaft vibes, too.
I was using them semi- disposibly in a 2002 race car where they went in and out
depending on tracks, so it was easy to check, and snug just a bit if needed.

hth, just a story.

t

[alpinewhite318i]

I was at 10 inch pounds and it seemed about right, then decided to go to 14 inches and it felt like the bearing was grinding. So I will start over again with a new crush sleeve. Do you recommend oiling up the bearing as well or using some kind of assembly lube? Thanks

[TobyB]

I just used gear oil-
and yeah, there's a point where it feels
'too tight'- I dunno if it IS,
but I redid them when they felt
that way, too. Maybe that's why mine sometimes
got loose...
t