(continued from previous page)
With all that done, we pop the crownwheel and cups back off again,
and start fitting up the pinion. First up drop in the outer pinion
bearing.....
followed by the seal.....
and then the inner pinion bearing is pressed on to the pinion shaft
and then the colapsable spacer(arrowed) is dropped on as well.....
this lot is then pressed into the casing and up through the outer
bearing. The pinion flange is popped back on and special tool
reattached.....
and the pinion nut is retightened.....
Theres no torque for this nut as again your using it to "preload" or
squeeze the two bearings below it just the right amount.
When retightening it you can feel the nut first tighten a little bit as
the outer bearing gets squashed up against the collapseable spacer,
but the pinion still is able to slap up and down in the direction below....
What has happened here is the both bearings have not been squeezed
close enough together yet and they can lift up and down off their races
because that collapsible spacer is keeping them apart.
So, the nut is tightened down more, slowley, crushing the collapsible
spacer till theres no up and down play and the bearings are sitting snugly
in their seats and then ever so slightly tightened again in little steps till the
right preload is got on the bearings. This extra bit of squash (preload)
on the bearings is done because when you nail the accelerator pedal
if the bearings were just fitted loosely they'd start to lift out of their
races and the pinion would start it's break for glory out through the
diff casing. Instead of leaving two nice big black tyre marks you end
up leaving one nice big trail of diff oil and gears.
Again there is a special tool for measuring the correct preload and
the figures for it are in the manual.
With everything tightened up correctly and a quick splash of holy water,
the lock washer is bent in to place....
casing is flipped over and crownwheel unit and cups refitted....
and halfshaft flanges refitted....
And then finally on to the most important check of the lot,
tooth contact. Some engineers blue....
spread evenly on 3 crownwheel teeth.....
and then rotate the diff gears by turning the front pinion flange while
putting a bit of loading on it by holding one of the output flanges loosely....
and what your left with should be a marking on the crownwheel teeth
of where the pinion teeth are contacting it. What your looking for is a
nice fat contact patch in the middle of the tooth, something like below....
If the contact patch is too high up towards the tip off the tooth you'll need
to move the pinion gear closer to the crownwheel by putting a fatter
shim under the inner pinion bearing.
And if it's too low to the base of the tooth you'll need to fit a thinner shim
to move the pinion gear back away from the crownwheel.
If the contact patch is too far towards the inside of the crownwheel tooth
then you've got to change the crownwheel bearing cup shims to move
the crownwheel away from the pinion gear.
And likewise if the contact patch is towards the outside of the tooth
change the cup shims to move the crownwheel towards the pinion
gear.
Again if none of the main components have changed during the overhaul
then the contact patch should be pretty close to right, but you still
gotta check. If you get the tooth contact patch badly wrong, then don't
worry to much about it, you'll be getting a chance to rebuild it all again
after a few miles, when it sh*ts itself.
After all that mind numbing crap is done, a bit of gasket sealer....
under the gasket and a little smear above....
bolt the rear cover back on....
pop the speedo sender back in with a fresh o ring....
bungs back in and fill with oil and thats it....
and all that waffle was for a case with 2 gears and 4 bearings,
I'm buying a new keyboard for whats coming next.....
till next time....
With all that done, we pop the crownwheel and cups back off again,
and start fitting up the pinion. First up drop in the outer pinion
bearing.....
followed by the seal.....
and then the inner pinion bearing is pressed on to the pinion shaft
and then the colapsable spacer(arrowed) is dropped on as well.....
this lot is then pressed into the casing and up through the outer
bearing. The pinion flange is popped back on and special tool
reattached.....
and the pinion nut is retightened.....
Theres no torque for this nut as again your using it to "preload" or
squeeze the two bearings below it just the right amount.
When retightening it you can feel the nut first tighten a little bit as
the outer bearing gets squashed up against the collapseable spacer,
but the pinion still is able to slap up and down in the direction below....
What has happened here is the both bearings have not been squeezed
close enough together yet and they can lift up and down off their races
because that collapsible spacer is keeping them apart.
So, the nut is tightened down more, slowley, crushing the collapsible
spacer till theres no up and down play and the bearings are sitting snugly
in their seats and then ever so slightly tightened again in little steps till the
right preload is got on the bearings. This extra bit of squash (preload)
on the bearings is done because when you nail the accelerator pedal
if the bearings were just fitted loosely they'd start to lift out of their
races and the pinion would start it's break for glory out through the
diff casing. Instead of leaving two nice big black tyre marks you end
up leaving one nice big trail of diff oil and gears.
Again there is a special tool for measuring the correct preload and
the figures for it are in the manual.
With everything tightened up correctly and a quick splash of holy water,
the lock washer is bent in to place....
casing is flipped over and crownwheel unit and cups refitted....
and halfshaft flanges refitted....
And then finally on to the most important check of the lot,
tooth contact. Some engineers blue....
spread evenly on 3 crownwheel teeth.....
and then rotate the diff gears by turning the front pinion flange while
putting a bit of loading on it by holding one of the output flanges loosely....
and what your left with should be a marking on the crownwheel teeth
of where the pinion teeth are contacting it. What your looking for is a
nice fat contact patch in the middle of the tooth, something like below....
If the contact patch is too high up towards the tip off the tooth you'll need
to move the pinion gear closer to the crownwheel by putting a fatter
shim under the inner pinion bearing.
And if it's too low to the base of the tooth you'll need to fit a thinner shim
to move the pinion gear back away from the crownwheel.
If the contact patch is too far towards the inside of the crownwheel tooth
then you've got to change the crownwheel bearing cup shims to move
the crownwheel away from the pinion gear.
And likewise if the contact patch is towards the outside of the tooth
change the cup shims to move the crownwheel towards the pinion
gear.
Again if none of the main components have changed during the overhaul
then the contact patch should be pretty close to right, but you still
gotta check. If you get the tooth contact patch badly wrong, then don't
worry to much about it, you'll be getting a chance to rebuild it all again
after a few miles, when it sh*ts itself.
After all that mind numbing crap is done, a bit of gasket sealer....
under the gasket and a little smear above....
bolt the rear cover back on....
pop the speedo sender back in with a fresh o ring....
bungs back in and fill with oil and thats it....
and all that waffle was for a case with 2 gears and 4 bearings,
I'm buying a new keyboard for whats coming next.....
till next time....
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