Page 91
Measuring
1. Check that the pointers of the instru
ment are zeroed when the measuring
. point touches Lhe gauge block (see il-
lustration).
2, Place the instrument in the differential
housing with the point applied to the
flat end of the pinion gear and lake a
reading (see illustration).
%, When the pinion gear is correctly posi-
tioned, the dial should show the same
reading (in hundredths of a millimeter
(, or -) as that stamped on the pinion
(with a permitted tolerance of + 0.05
mm).
Shimming
If the measured reading is outside the
permitted tolerance, the pinion shaft must
be adjusted. This is done with shims placed
between the pinion shaft bearing housing
and the transmission case (see illustration).
473-2
Page 92
Shim table
Shims
Location Thickness Spare part
; mam Na,
Pinion shaft 0.10 83 41 752
between bearing | 0.15 83 41 760
housing and tran-| 0.30 83 41 778
smission case 0.50 83 44 723
Procedure for shirnmming is as follaws:
1. Undo the four bolts from the pinion
shaft bearing housing and tap Lhe pinion
shaft gently out of the transmissian
ease.
» Change the shimming according to the
following rules:
a) If the dial readiny is higher Lhan the
correct value, increase the shim
combinatian.
b) Tf the dial reading is lower than the
correct value, reduce the shim com-
bination.
ns
Note! « reads caunter-clackwise and -
reads clackwise on the dial.
Reduce or increase the shim combina-
tion by the difference between the
measured and correct values.
If the pinion is starmped -7, the pointers
should indicate -0.07 mm. A deviation of
+ 0.05 mm from this reading is permitted.
%. Waving selected the correct combina-
tion of shims, place them in the trans-
mission case with aid of the lacating
pins. Mount the pinion shaft to the
Lransmission case using sileave
83 90 148 and arbor 83.90 114. Remove
the locating pins, apply Loctite to Lhe
bolts and then tighten them to the
prescribed torque.
“Pl
hae i
KA
) WS
We Silt,
<r
1 5 1845
Adjusting the pinion gear
1. Shim
2. Roller bearing
3. Bearing housing
4, Pinion
S487
473-3
Page 93
Rechecking
After shimming, replace the measuring jig
in the differential housing and check that
the dial now gives the correct reading to
within + 0.05 mm. If it does not, the
shimming procedure must be gone through
again.
If the pinion is stamped +3, the dial should
indicale +0.03 mm. A deviation of + 0.05
mm from this reading is permitted.
Checking the measuring jig
The measuring jig is a precision-made tool.
It should be handled with eare to avoid
knocks and deformation. If there is reason
to suspect that the jig may have been
damaged in such a way that it gives wrong
readings, it can be checked. The dimension
indicaled in the illustration on the right
should be measured for this purpase.
Adjusting crown wheel backlash
Certain data for adjustment of crown
wheel backlash are stamped on the crown
wheel as illustrated.
Note
With new details the backlash should
be adjusted to 0.1 | 0.05 mm.
Details with less mileage than 6.000 miles
(10.000 km) should be adjusted to 0.17 4
0.05 mm.
473—4
“S$ 4198
870488 9:33 8401 O2 -17 1330
S 4568
Crown wheel markings
870488 = Item number (not part number)
9:33 = Ratio
84-01 = Date of manufacture and iden-
tifacation code
02 = Material eode
-17 - Backlash of 0.17 mm. Unless
otherwise stated, this has a Lo-
lerance of 0.05 mm.
Mating number, which is also
stamped on the pinion
1330
Page 94
ae
The backlash should be checked at Table of shims
four points round the circumference of
the crown wheel and must not deviate —
by more than + 0.05 mm from the , Shims
stated measurement. Crown wheel | ocatian Thickness io part
backlash is adjusted with shims. Up to ; mm r
four shims in suitable combinations aint diffe- aad ri re a
may be eed, rential bearing 5x5
4 seal. and tran- 0.30 83 41 620
smission case 0.50 83 44 638
Measuring and shimming
Adjustment of differential bearings
eee
Adjustment must be carried out before
the pinion shaft is mounted. (If only
the final drive has been dismantled for
the replacement of the differential
bearings, the crown wheel must also
be dismantled before the bearings can
be adjusted.)
l. Place the differential assembly com-
plete with crown wheel in the trans-
mission case.
2. Mount the left bearing seat (with the
speedometer drive) without shims and
tighten the bolts to the prescribed
torque.
Tightening torque,
left-hand bearing seat
20-25 Nm (2.0-2.5 kgfr, 14-18 Ibft, )
——EEe
3. Oil the differential bearings and mount
the right bearing seat. If the inner drive
is mounted in the bearing seat, remove
the spring and plunger before mounting
the seat. Tigthen the bolts, in two or
three stages, to the prescribed torque.
Rotate the differential while tightening
the bolts.
Tightening torque,
right-hand bearing seat.
2.2 Nm (22 kgfern; 19 Ibin)
473-5
Page 95
4. Measure the gap between the trans
mission case and bearing seat with a
| feeler gauge at two points opposite
each other and take an average of the
two measurements. Then select shims
corresponding ta this result plus an in-
crement. of 0.20 mm Lo obtain the cor-
rect bearing Compression.
The method described above applies to
| both new and old bearings.
. The torque obtained in this way ean be
: measured by means of a torque wrench and
| driver 87 90 818.
Ensure that you adjust Lo the correct. va-
lues. The following values apply for the
i rolling torque.
. ——
tl New, ligthly oiled bearings: ff
4! 1.8-2.8 Nm (16-24 Ibin, 18-28 kgfem)
:
Bearings having run more than 1 200
miles (2 000 km) 0.8-1.3 Nm (7-11 Ibin,
8-13 kgfem)
SS
H! Shims of four different thicknesses can be
suitably combined. The available
thicknesses are shown in the table below.
Note al
The resulting set of shims should then
be distributed between the right and
left sides Lo give the correct backlash.
Shims
Location Thickness Spare part
mm No. _
Between diffe- 0.10 83 41 604
rential bearing 0.15 83 41 612
seat and tran- 0.30 83 41 620
smission case 0.50 83 44 638
Page 96
ey
°
Adjusting crown wheel gear backlash
1. Place the differential assembly corm-
plete with crown wheel in the trans-
mission case.
2. Mount the left bearing seat (with the
speedometer drive) without shims and
the right bearing seat with the se-
lected set of shims, tightening the
bolts Lo the prescribed torque.
Tightening torque,
LH and RH bearing seat:
20-25 Nm (2.0-2.5 kof: 18 Ibft. )
3. Mount the dial indicator, see illustra-
tion, and measure the backlash.
4. Calculate the difference between the
measure backlash and the desired back-
lash, and then move shims of suitable
thickness aver to the left bearing seat.
Check the measurement once again.
The preselected set of shims must be
used for adjusting the backlash. The
total thickness of the set must not be
altered.
Differential
Removing (Earlier versions)
To replace parts inside the differential,
remove one of the circlips on the diffe-
rential drive shaft. The shaft, drive and
wear washers can be removed without the
crown wheel having to be dismantled.
1. Remove the differential housing cover.
2. Remove the two differential bearing
seats together with inner drivers. Save
any shims and remove the differential.
3. If necessary, press the outer bearing
rings out of the bearing seats (see Dis.
mantling of the inner driver with diffe-
rential bearing cap), Remove the spee-
dometer drive and Press both journal
bearings off the differential housing us-
ing tools 8996084, 87 90 768 and
89 95 177.
4. Remove the crown wheel bolts and take
off the crown wheel.
>. Push out the differential gear shaft.
The hole marked by a white dot is
slightly smaller-the shaft should
therefore be pressed out fram this side.
6. Remove the gears and the wear washers
from the differential Casing.
= ;
473-7
Page 97
Assembling
| Ass
Important
If the crown wheel is exchanged, the
pinion gear must be exchanged with it,
as these two parts constitue a mat.
ehing pair.
Exchange any worn or damaged parts.
Locate the gears and wear washers in
the differential casing and slide in the
differential drive shaft. The shaft
should be inserted from the side marked
with a white dot.
ne
* *
3. Mount the crown wheel, apply locking
fluid to the bolts and then tighten them
to a torque of 50 Nm (5.0 kgfm; 36 Ib
ft). Tightening torque as from 1982
models, with a final drive ratio 9.33,
the modified bolts (10 x 1.25) should be
tightened to a torque of 90 + 10 Nm (9
+ 1 kgfm, 63 + 7 Ib ft).
4. Press on the journal bearings and the
speedometer drive, if these have been
removed, using Loo] 87 90 487.
5. Locate the differential assembly in the
transmission case. If any part affecting
the overall width of the differential
assembly - e.g. the bearings - has been
exchanged, the crown wheel backlash
must be adjusted. This is done by alte-
ration of Lhe combination of shims. See
seclion "Adjusting crawn wheel back-
lash".
WN 6. For fitting of the outer bearing rings in
) the bearing seats, see under "Inner dri
i! ver with differential bearing seals -
assembly". Fit the differential bearing
seats and the inner driver. Coat the
1) threads of the 12 bolts with sealing
compound.
Tightening Lorque,
differential bearing seat:
20-25 Nm (15-19 Ibft, 2.0-2.5 kgfm)
7. Fit the rear cover of the differential
housing.
473-8
Page 98
Differential
(New version)
To
dismantle the differential
1.
2.
-
4.
Tightening torque:
90 » 10 Nm (9 + 1 kfgq m)
Remove the final drive cover.
Remove the two differential bearing
seats together with the inner drivers.
Save the shims and remove the differ-
ential.
Remove the speedometer drive and
press off the journal bearing using tools
89 96 084, 87 90 768 and 89 95 177. To
change the outer bearing races, refer to
the section on dismantling of the inner
driver.
- Remove the locking pin from the dif-
ferential shaft and carefully tap out the
shaft. Save the gears and the wear
washers.
Undo the crown wheel bolts and remove
the crown wheel.
assemble
Exehange any worn or damaged parts.
Refit the journal bearings and the
speedometer drive, using tool
87 90 487.
Mount the differential and differential
bearing seats inside the transmission
ease. Check the bearing preload and
adjust the shims as necessary (refer to
"Inner driver with differential bearing
seats"),
Remove the differential and bearing
seats fram the transmission case.
. Fit the crown wheel, tighten the bolts
to the specified torque and apply lock-
ing fluid to them.
e
»
ae &
oO w
oe
v o
Fi § S899
473-9
Page 99
6. Fit the gears and wear washers and
insert the differential shaft. Fit the
locking pin.
7. Mount the differential and differential
bearing seats in the transmission case.
8. Check the crown wheel backlash and
adjust as necessary (see the section on
the inner driver with differential bear-
ing seats.)
9. When finally fitting the differential
bearing seats, apply sealing compound
to the 12 bolts.
Tightening torque: |
20 - 25 Nm (2 - 2.5 kfg m)
10. Refit the final drive cover.
Inner driver with differential bearing seats
Removal
Remove the differential bearing cap re-
taining bolts and remove the cap and inner
driver using tool 8790776 and tool
83 90 270. Save the shims.
Dismantling
1. Remove the circlip from the driver.
473-10
237
Page 100
2. Press out the driver from the differen-
tial bearing seat.
3. Using a screwdriver, remove the seal
ring taking care not to damage the
bearing seat.
4. Remove the speedometer drive from
the left bearing seat.
5. Press out the ball bearing using tool
78 41 067.
6. Remove the bearing lracks for Lhe dif-
F ferential bearings by means of a suit-
able drift. A washer is located inside
the bearing track for the right-hand
differential bearing seat (seat without
speedometer drive) and the purpose of
i this is Lo improve the bearing lubrica-
i tion.
7. Remove the O-ring from the groove in
the bearing seat.
Inner driver and bearings
: 1. Inner driver
2. Spring with plunger
3, Sealing ring
4. Seat
5. Ball bearing
« in) 6. Circlip
7. Oil level washer
8. Bearing track
9. O-ring
. Assembly
1. Press the ball bearing into the bearing
| seat using tool 78 41 141.