Defender (1993+). Manual — part 69

FRONT

AXLE AND

FINAL DRIVE

3. Fit a suitable socket to the torque pre-load

meter M.S. 103 or a suitable alternative, and
check the pre-load figure by turning the
pinion, with the meter, in a clockwise
direction. Continue to tighten the nut until the
gauge reads 2 to 4 Nm.

4. Note that i f the original, bedded-in, bearings

are being refitted the pre-load figure should be

1.2 to 1.7 Nm.

The object of the following instructions is

to

establish

the correct height of the pinion, in the pinion
housing,

so that it

will

mesh correctly with the crown

wheel. This may entail raising or lowering the pinion
by adjusting the value of the shims behind the pinion
head bearing track. In order to achieve this, the
pinion bearings must be temporarily pre-loaded

to

the same figure as they will be when the differential
is finally assembled.

2. Insert the pinion into the housing and

fit

the

tail bearing without any pre-load shims. Fit the
spacer and drive flange, omit the oil seal, and
secure the assembly with the washer and nut.
Restrain the flange with service

tool

18G

1205

or the reverse end

of

RO

530105,

and slowly

tighten the nut

a little at a time and remove

the flange restrainer.

5. Secure the pinion housing vertically in the vice

so that the pinion is uppermost. It will be
noted that in addition to the serial number
etched on the pinion end face there may be a
figure with a minus (-) or a plus (+) sign
before it. This figure indicates, in thousandths
of an inch, whether the depth of the pinion
head, (dimension A), is under or oversize from
the designed dimension. A pinion without
these figures must be set in the pinion

housing at the nominal height dimension. The
nominal height dimension is represented by

the pinion height setting block 18G191-4. The
dimension

I

S

taken from the pinion end face to

the lowest point i n the differential carrier

bearing saddle in the pinion housing.

FRONT

AXLE AND FINAL DRIVE

7 .

Ensure that the pinion head is clean and

smooth. Transfer the gauge

to

the pinion

housing

so that the magnetic base sits

centrally on the pinion end face and the stylus
rests on the lowest point

in

one

of the carrier

bearing saddles.

Make

a note

of the dial

gauge reading

from the zeroed setting and

whether the gauge needle moved up

or down.

Now move the dial gauge across

to

the other

saddle and again note the reading from the
zeroed setting. Now add the two readings
together and divide by

two

to

obtain a mean

reading.

6. Remove the keep disc from the magnetic

base of the pinion height setting dial gauge

18G 191 and position the setting block 18G
191-4 and gauge on a surface plate as

illustrated. It will be noted that the setting
block has three setting heights. It is essential

that the correct setting is used for the
differential concerned. Rest the stylus on the
setting and load the gauge to read
approximately 0,40 mm and zero the gauge.

8. I f the dial indicator needle did not reach the

zeroed setting, the difference between this

NOTE: The setting block dimensions are as

setting and the position of the needle is the

follows: 39,50 mm Rationalised axle - Latest

thickness of shims that must be removed

from

current axle metric threaded bearing

cap bolts.

behind the pinion head bearing track to lower

38,10

mm Pre-Rationalised axle recognized by

the pinion to the nominal dimension.

the

A/F

threaded bearing

cap bolts.

30,93

mm

9. I f the indicator needle moved beyond the

Salisbury axle only.

zeroed setting, the difference between this
setting and the position of the needle is the
thickness of shims that must be added to
those behind the pinion head bearing track to

raise the pinion to the nominal dimension.

I

I

FRONT AXLE

AND

FINAL

DRIVE

face figure of + 3 the dial gauge reading

should indicate that the pinion head depth is
indeed 0.003 in (0.0762 mm) oversize.

Pinion bearing pre-load adjustment

1.

Position the pinion housing horizontally in the

vice. From the pinion housing remove the
drive flange, spacer, tail bearing and pinion.

2. Fit a new shim or shims

of

the same

thickness as the originals to the pinion.

If

these are lost and the thickness is unknown

fit

shims

to

the value

of at least 4,06 mm.

3.

Fit the pinion,

with

the shims,

to

the housing,

then the tail bearing followed by the spacer

and driving flange. Omit the oil seal at this
stage and secure the assembly with the
washer and castellated nut.

10.

Before actually adjusting the shim thickness,

the plus

or minus figure,

if

any, on the pinion

face must be taken into consideration when
calculating the final thickness of shims that

must

be removed or added.

4. Tighten the flange nut

to the specified torque

If the pinion has a plus

(+)

figure etched

on

whilst holding the flange with service

tool

18G

the pinion face, subtract this figure, in

1205, as before. The torque now required to

thousandths of an inch, from the figure

turn the pinion,

if

new bearings have been

obtained

in instruction

8

or

9.

If the pinion has

fitted, should be between

2

to 40 Nm once the

a minus

(-)

figure on the pinion face add this

initial inertia has been overcome.

If

the

to that obtained

in instructions

-

or

9.

A pinion

original, bedded-in, bearings have been

without a plus or minus figure must

be

refitted, the figure should be between 1.2

to

adjusted

to the nominal dimension and shims

1.7

Nm.

To check the torque

or pre-load, use

to

the value indicated by the dial test indicator

the Torque meter

M.S.

103

and a socket and

in instruction -

or

9 should be added

or

turn the pinion whilst noting the meter reading.

removed.

If necessary, dismantle the pinion assembly

11.

Remove the pinion from the housing and

and change the bearing pre-load shims

in

withdraw the pinion head bearing track as

order

to achieve the correct torque figure. As

previously described.

Adjust

the

shim

a guide, thicker shims will reduce the torque

thickness

as

required by

the

above

or pre-load and thinner shims will increase the

calculations. Refit the bearing track and shims

torque. Reassemble the pinion again and

and ensure that once again the track is

recheck the torque.

pressed

fully home,

12.

Having made the necessary adjustments the

pinion height setting must be checked again to

1

Having established the correct thickness of

ensure that the calculations and adjustments

shims the pinion drive flange

must be

removed to fit the oil seal. Examine the seal

are correct. Refit the pinion

to

the housing

and pre-load the bearings, as before,

before fitting

to ensure that

it

is clean and

repeating instructions 2 and

3

above. Now set

undamaged, since even a small scratch

on

up the dial gauge and carry out the pinion

the seal lips could impair its ability

to

prevent

height check again exactly as described in

oil leaking. Also check that the garter spring is

instructions

6

and

7.

If

the pinion height

properly located. Whilst the distance piece can

setting

is

correct, the mean reading obtained

be inserted after the seal has been fitted, the

will

agree with the figure etched on the pinion

tail bearing will not pass through the seal,

so

Fitting pinion

oil seal

it is important to check that the bearing is in

FRONT AXLE AND FINAL DRIVE

5.

After evenly tightening the bearing cap bolts
to

the correct torque, check the backlash

again to ensure that it has not altered the

setting. Fit the locking finger and secure with
the roll pin.

6. Locate a new joint washer over the axle

casing studs, liberally lubricate the bearings
and gears and refit the differential assembly to
the axle.

Fit

and tighten the retaining nuts

evenly

to

the correct torque.

7. Check that the drain plug is tight and remove

the

axle

oil

filler

level

plug.

Inject

approximately 1,70 litres of a recommended
axle

oil

until it begins

to

run

from

the level

hole. Fit and tighten the plug and wipe away
any surplus oil.