Vehicles after change point in 1982
REPLACING BEARINGS FOR
DRIVE PINION
- Final Drive Removed -
See 33 10 010 in microfilmed repair manual
for cars beginning with 1985 models for
information on removing final drive.
Mount final drive on Special Tool 33 1 010.
Drain oil.
Unscrew case cover.
Installation:
Replace gasket.
Tightening torque*.
Pour in oil - oil volume*.
See Group 33 in Operating Material Binder
for approved oil grade.


33 10 010
* See Specifications

Pry off drive flanges with a tire iron.

Installation:
Place round wire snap ring (1) in groove of
differential case prior to installation of drive
flange in such a manner, that both ends of
snap ring are recessed in groove.
This prevents lateral bending of snap ring.
Press in drive flange by hand and turn
slightly, until snap ring is heard to engage.
Replace stretched snap rings.

Punch mark both bearing caps.
Unscrew bolts of both bearing caps and take
off bearing caps (turn if necessary, since seals
suck tight).
Important!
Don´t mix up bearing caps and shims.
If necessary, fasten shims on bearing caps with
pieces of wire.
Installation:
Tightening torque*.


* See Specifications

Axial preload force (4000 N = 882 lbs.) of
differential bearings and backlash of ring gear/
pinion are adjusted with shims (1).

Remove complete differential case.
Important!
Don´t bend the pulse spider.

Lift out lockplate.

Hold input flange with Special Tool 23 0 020
and unscrew the collar nut.

Pull off input flange with Special Tool
33 1 150.
The specified friction torque* is given for
new bearings and friction torque of old
bearings does not have to be measured.


* See Specifications

Press out drive pinion.
Caution!
Be careful not to damage threads.

Pull out front bearing outer race with Special
Tool 33 1 350.
1 Spreader
2 Front bearing outer race
3 Puller bell housing
4 Pressure bolt

Pull out rear bearing outer race with Special
Tool 33 1 360.
Puller consists of:
Puller head.................. 33 1 361
Threaded spindle.........33 1 362
Bearing bridge............. 33 1 356
Pressure nut................ 33 1 363
Important!
Shim (X) is located underneath the rear bearing
outer race.
It will be needed again for the block distance
adjustment.

Install old shim (X) in front of the rear bearing
outer race.
Pull in bearing outer races with Special Tool
33 1 360.
Puller consists of:
Puller disc for front outer race..... 33 1 373
Puller disc for rear outer race...... 33 1 365
Threaded spindle........................ 33 1 362
Pressure nut................................ 33 1 363
Nut.............................................. 33 1 354

Pull tapered roller bearing off of drive pinion
with Special Tool 33 1 300.
Caution!
Be careful not to damage the pinion - use soft
aluminum jaws or pieces of wood.

Press new tapered roller bearing on to drive
pinion with Special Tool 33 1 020.
Important!
Always only use both bearings of same make.

The drive pinion is installed with new tapered
roller bearings, but without clamping sleeve,
to determine correct thickness of shim (X).

Install drive pinion in rear bearing outer race.
Pull front tapered roller bearing on to drive
pinion with Special Tool 23 1 300 in conjunction
with a spacing sleeve.

Mount input flange.
Adjust the friction torque of the drive pinion
bearings to 250 Ncm (22 in.lbs.) by tightening
the collar nut carefully.

Important!
Measure friction torque at intervals during the
tightening procedures with Special Tool
00 2 000.

Block Distance of Drive Pinion:
Mount dial gage in Special Tool 33 1 461.
Place Special Tool 33 1 461 with dial gage on
Special Tool 33 1 462 and set dial gage to 0
(zero) with preload.

Place Special Tool 33 1 462 on drive pinion.
Place Special Tool 33 1 461 in case.
Determine value Y:
Basic distance......... C = 11.50 mm (0.453´´)
Gage thickness....... B = 9.50 mm (0.374´´)

Examples for Determination of Correct Shim Thickness (X)
Example I
C........................................ 11.50 mm (0.453´´)
e+........................................ 0.10 mm (0.004´´)
_____________________________________
C nominal.............................11.60 mm (0.457´´)
Y measured on dial gage....... 1.90 mm (0.075´´)
+ gage thickness................... 9.50 mm (0.374´´)
_____________________________________
C actual................................11.40 mm (0.449´´)
C nominal..............................11.60 mm (0,457´´)
C actual..............................- 11.40 mm (0.449´´)
_____________________________________
a.............................................0.20 mm (0.008´´)
Gage thickness A...................4.10 mm (0.161´´)
- a...........................................0.20 mm (0.008´´)
_____________________________________
Shim thickness (X)..................3.90 mm (0.153´´)
If C nominal is larger than C actual, "a" is
subtracted (-) from shim thickness X.
Example II
C...........................................11.50 mm (0.453´´)
e-............................................0.10 mm (0.004´´)
_____________________________________
C nominal..............................11.40 mm (0.449´´)
Y measured on dial gage........2.20 mm (0.087´´)
+ gage thickness....................9.50 mm (0.374´´)
_____________________________________
C actual.................................11.70 mm (0.461´´)
C actaul.................................11.70 mm (0.461´´)
C nominal.............................- 11.50 mm (0.453´´)
_____________________________________
a.............................................0.20 mm (0.008´´)
Gage thickness A...................3.90 mm (0.153´´)
+a...........................................0.20 mm (0.008´´)
_____________________________________
Shim thickness (X)..................4.10 mm (0.161´´)
If C nominal is smaller than C actual, "a" is
added to shim thickness X (+).
The permissible tolerances for distance (X) result from the tolerances for shim thicknesses which
are available in steps from 0.01 to 0.03 mm (0.0004 to 0.0012´´).

Remove drive pinion after determining the
thickness of shim (X).
Important!
Note make of bearings - this is required for
determination of friction torque.

Remove rear bearing outer race and install
again with shim (X) of determined thickness.

Install drive pinion with new clamping sleeve
(2).

Dip shaft seal in final drive gear lube and
drive in flush with Special Tools 33 1 270
and 00 5 500.

Press (don´t pull) input flange on to the input
shaft with Special Tool 23 1 300.
Axial preload force (5000 N = 1102 lbs.) of
drive pinion bearings can be determined with
help of the friction torque.

Tighten input flange with the collar nut in
steps, measuring the friction torque after each
step (see below).

Measure friction torque* with Special Tool
00 2 000 and a suitable wrench socket.
Important!
The relation between friction torque and
preload force differs depending on the make
of bearings.
Take the specified friction torque from the
pinion bearing table* and add 20 Ncm (2 in.lbs.)
for the new shaft seal.


* See Specifications

Install differential.
Install side covers as marked with corresponding
washers (1) and new O-rings (2).
Tighten bolts uniformly.
Tightening torque*.


* See Specifications

- Backlash/Tooth Contact Pattern Adjustment -
Mount Special Tool 00 2 500 and measure
backlash* with dial gage.
Important!
The tooth contact pattern is always most
important for a perfectly adjusted pinion/ring
gear set.


* See Specifications

To check the tooth contact pattern, coat the
ring gear teeth with printer´s ink, turn in both
directions several times and stop ring gear suddenly
with a piece of hard wood.

Correct backlash* and tooth contact pattern
by changing the thickness of both shims (1).
If backlash is excessive, use a thinner shim on
the ring gear end.
If backlash is too small, use a thicker shim on
the ring gear end.
An axial displacement of the ring gear by 0.01 mm
(0.0004´´) will cause a change in backlash
of 0.076 mm (0.0003´´).
Important!
The total thickness of both shims must not be
changed.


* See Specifications

If a thinner or thicker shim is required to correct
the tooth contact pattern, the total thickness
must be corrected with the second shim,
since otherwise the friction torque of bearings
would be changed again.
See "Replacing Differential Bearings" in
33 11 731 for information on determining
friction torque of differential bearings.


33 11 731

See "Replacing Drive Pinion and Ring Gear" in
33 12 551 for general information on tooth
contact pattern adjustments.


33 12 551

Pull out old shaft seals with Special Tool
00 5 000 or 00 5 010 in conjunction with a
thrust piece.

Installation:
Dip new shaft seals in final drive gear lube.
Drive in shaft seals against the stop with
Special Tools 33 1 230 and 00 5 500.
Replace a drive flange with seriously scored
bearing surfaces.

Drive in new lockplate with Special Tools
33 4 050 and 00 5 500.