Ford Falcon. Manual — part 51

205-02A-28

Rear Drive Axle / Differential — Beam Axle

205-02A-28

DISASSEMBLY AND ASSEMBLY (Continued)

3. To establish the thickness of the spacers

12. Remove the assembly from the carrier using the

required:- Total the thickness of the two spacers -

spreader. If the preload is correct, tie the selected

Add the gap measured with the feeler gauges.

spacers to the bearing cups to have them

Add 0.15 mm when using new bearings or 0.1

available for use in determining gear backlash. If

mm when using used bearings to preload the

correct preload is not obtained, a variation of

bearings.

0.025 mm on spacers will alter preload 8 N for

new bearings and approx. 4 N for used bearings.

4. Select two spacers, each half the thickness of the

Repeat steps 5-12.

value determined in Step 3.

5. Fit the carrier spreader adaptors and the spreader

Drive Pinion Position — Shim

to the carrier, together with a dial indicator

Selection

positioned over the carrier differential opening, as

close as possible to the centre line of the axle

NOTE: The drive pinion and ring gear set

shafts. This may be done by using a pilot stud

identification marking (number 5K-25) is the matching

screwed into the side bearing lower stud hole,

number that appears on both the drive pinion and the

with the dial indicator plunger in contact with the

ring gear. When a new gear set is being installed in

opposite side of the carrier opening.

an axle, be sure that the same matching number

6. Use the spreader to expand the case until the

appears on both the drive pinion and the ring gear.

differential assembly with bearings and selected

spacers will fit into the carrier. A spread of 0.25 to

0.3 mm is usually sufficient. Under no

circumstances should the carrier be spread

more than 0.50 mm.

7. The differential assembly, with bearing cups and

selected spacers held against the bearing cones,

may now be fitted to the carrier, after removing

the dial indicator.

8. Release and remove the spreader tool leaving

adaptors in position.

9. Fit the bearing cups in their original positions,

tightening the bolts to 55 Nm torque.

10. Rotate the differential assembly at least six full

turns to seat the bearing rollers in the bearing

Pinion/Ring Gear Identification

cups.

11. Check the preload using a spring balance.

Measure the tension required to revolve the

assembly when a string is wrapped around the

differential case on the larger diameter, just

behind the drive gear. Balance readings must be

within the following limits: New bearings 25

± 10

N. Used bearings 13

± 5 N. These balance

readings are equivalent to the preload torques in

the Specifications.

NOTE: The ring gear and pinion are manufactured

within a tolerance of a specified distance. On the end

of each pinion, there is marked a plus (+) number, a

minus (-) number, or a zero (0) number which

indicates the best running position for each particular

gear set. This dimension is controlled by the

shimming behind the rear pinion bearing cup. When

the shim thickness is decreased, the pinion gear is

moved away from the ring gear. When the shim

thickness is increased, the pinion is moved closer to

the ring gear. A positive (+) number on the drive

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205-02A-29

Rear Drive Axle / Differential — Beam Axle

205-02A-29

DISASSEMBLY AND ASSEMBLY (Continued)

pinion means that a thinner shim should be installed

increments from .008 to .030 in (0.2 to 0.75

to move the pinion gear away from the ring gear. A

mm

negative (-) number means that a thicker shim should

NOTE: The marking on the pinion is in

be used to move the drive pinion closer to the ring

Imperial measurement.

gear.

5. Remove the tools from the carrier.

To select the correct shim thickness follow these

6. Remove the rear pinion bearing cup from the

steps:

housing.

NOTE: Lubricate all differential parts with the

Drive Pinion and Bearings

recommended rear axle lubricant, before they are

installed.

NOTE: Refer to special tools in this section.

NOTE: The exact same rear pinion bearing that is to

NOTE: All hardware must be correctly installed and

be used in the vehicle, is to be installed when using

torqued to specification.

the dummy pinion.

1. Place the pinion rear bearing cone on the pinion

1. Install the front and rear pinion bearing cups into

shaft. Press the bearing against the pinion shaft

the axle housing. Fit the pinion bearing cone and

shoulder.

rollers to the dummy pinion tool. Install the

dummy pinion to the axle housing. Fit the pinion

2. Install the shims (previously established), between

front cone and roller to the dummy pinion. Install

the rear bearing cup and the housing and install

the tool thrust collar and the nut to the dummy

the new cups using the Special Tool. Make sure

pinion.

the cups are properly seated in their bores. If a

0.025 mm feeler gauge can be inserted between

a cup and the bottom of its bore at any point

around the cup, the cup is not properly seated.

2. Tighten the nut until a bearing preload of 1.4 to

2.4 Nm (new bearing), 0.7 to 1.2 Nm (used

bearing) is achieved while rotating the dummy

pinion back and forth to ensure correct seating of

Item

Description

the bearing rollers.

1

Tool - E3C10AER Installer Drive pinion

3. Position the depth gauge cylinder in the carrier

rear bearing

and fit the bearing caps, tightening lightly.

2

Bearing cone and roller

4. Determine the size of pinion shim that will pass

3

Drive pinion

between the depth gauge and the dummy pinion

head. Examine the drive pinion installation

3. Lubricate the pinion rear bearing with axle

marking. The size of the pinion shim should then

lubricant.

be altered as follows:

4. Position the pinion in the carrier and install a new

A positive (e.g. +0.002 inch) marking means

collapsible pinion spacer.

that this pinion has to be set at this number of

5. Lubricate the front pinion bearing and install the

thousandths of an inch further from the drive

bearing onto the pinion while supporting the

gear, i.e. a shim this amount thinner must be

pinion under the head.

used.

6. Lubricate the seal lips and the seal outside

A negative (e.g. - 0.002 inch) marking means

diameter, and install the seal from flush to 0.25

that a shim this size thicker must be used. A

mm below the carrier surface.

zero (0) marking indicates that the shim

selected with the gauge is the correct one for

this carrier/pinion combination. Position shims

are available in .001 in (0.025 mm)

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205-02A-30

Rear Drive Axle / Differential — Beam Axle

205-02A-30

DISASSEMBLY AND ASSEMBLY (Continued)

7. Install the pinion flange and nut. Tighten the nut

Differential Case — Conventional Type

while rotating the pinion backwards and forwards

M78 and M86

to seat the bearings. Check the bearing preload

frequently while tightening the nut. Tighten the nut NOTE: Refer to special tools in this section.

until the specified bearing preload is achieved. 1.4

Nm to 2.4 Nm with new bearings. 0.7 Nm to 1.2

Disassembly

Nm with used bearings.

1. Remove the bolts that attach the ring gear to the

NOTE: If the preload is exceeded the collapsible

differential case.

spacer must be replaced.

CAUTION: All axles use LH thread ring

Differential Installation and Backlash

gear bolts - identified by L on bolt head. Press

Check

the ring gear from the case or tap it off with a

softfaced hammer.

NOTE: All hardware must be correctly installed and

2. With a suitable drift, drive out the differential

torqued to specifications.

pinion cross shaft retainer pin.

1. Install the differential assembly with the tentatively 3. For M78 use a soft drift to separate the two piece

selected spacers in the carrier, following the

differential case.

procedure in Differential Bearing Preload Spacer

4. Drive out the differential pinion cross shaft from

Selection steps 4 to 9 inclusive.

the larger section of the case. Lift the pinion gears

2. Measure the backlash as detailed in this section.

and thrust washers from the case.

Measure the backlash on several teeth around the 5. Remove the side gears and thrust washers from

ring gear to find the minimum position. Backlash

each section of the case.

here should be 0.13 to 0.18 mm. If the backlash is

6. Remove the differential bearings. Discard

not within the range, decrease the thickness of

bearings whenever they have been removed from

one differential bearing spacer and increase the

the carrier.

other by the same amount. The amount of change

of each spacer is approximately equal to the

7. For inspection after removal and dismantling refer

amount of change required to correct the

to Section 204-02b.

backlash reading. It is most important that the

Assembly

total thickness of both spacers be the same after

backlash adjustment as before, so that correct

NOTE: All hardware must be correctly installed and

preload is retained.

torqued to specification.

3. Check the gear tooth contact pattern as detailed

1. Lubricate all the differential parts with the

in Section 308-03.

recommended rear axle lubricant, before

4. Fit the rear cover to the carrier using silicone

installation.

rubber sealant. Fit the park-brake cable clips. On

2. Place the side gear thrust washers over the side

Wagon models fit the protection bracket to the

gear journals.

differential cover.

5. Install the axle shafts as described in this Section.
6. Align the marks on the driveshaft and pinion

flanges and connect the driveshaft. (Refer to

Section 205-01.)

7. With the vehicle in the curb load position fill the

axle to the bottom of the filler plug hole with the

correct lubricant.

Item

Description

1

Tool - Push/puller with legs

2

Tool - Stepped plug

3

Tool - Knife edge puller

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205-02A-31

Rear Drive Axle / Differential — Beam Axle

205-02A-31

DISASSEMBLY AND ASSEMBLY (Continued)

3. Position a side gear in the larger section of the

6. For the cone/ side gear sub-assemblies, slide the

differential case.

cone off the splines on the side gear, this will

reveal one thrust washer and two spring washers.

4. Position the two differential pinions and the thrust

NOTE: Ensure the mating cone, side gear, thrust

washers in the large section of the case.

washer and spring washers are not interchanged

5. Drive the pinion cross shaft into position. Ensure

with components of the other cone/ side gear

that the retainer pin hole is in line with the hole in

sub-assembly.

the case. Take care not to damage the differential

pinion thrust washers.

7. For inspection after removal refer to the General

Procedures.

6. Drive the pinion locking pin through the differential

case and pinion shaft. Ensure the pin does not

Assembly

protrude from the underside of the larger

NOTE: All hardware must be correctly installed and

differential case.

torqued to specification (see Specifications section).

7. Install the second side gear and thrust washer in

the smaller section of the case.

1. Lubricate all the differential parts with the

recommended rear axle lubricant before

8. Holding the side gear in position through the case

installation.

bore, push the two sections of the case together

locating on the retaining pin. Rotate the side gear, 2. Place a side gear face down. Slide two spring

if necessary, to ensure that the gear and pinions

washers onto the gear’s splines with the convex

are meshing correctly.

side facing up. Next, slide one side gear thrust

washer onto the splines. Finally, slide a cone face

9. Place the ring gear in position on the case. Install

down over the gear splines.

and torque the bolts.

3. Clamp an axle shaft in a vice with approximately

10. Press the differential side bearings onto the case

75mm of the splined end extending above the

journals.

vice jaws.

Limited Slip Differential — M78

4. Place the cap section of the differential case, with

the interior facing upwards, over the extended

NOTE: Refer to special tools in this section.

tool/ axle shaft spline.

5. Place the assembled cone/ gear sub-assembly

Disassembly

face up into the differential case.

1. Place the assembly in a vice equipped with

6. Install the pinion shaft locking pin into the pinion

copper jaws.

shaft seat on the differential case.

2. Remove the bolts holding the cap and flange

7. Install the pinion shaft, together with the pinions

sections of the differential case together and

and thrust washers, onto the locking pin and the

separate the sections.

differential case.

NOTE: Ensure the cone/ side gear

8. Assemble the remaining cone/ side gear

sub-assemblies are not interchanged during

sub-assembly, as per Step 2, and place face up

reassembly of the differential. Mark the mating

into the flange section of the differential case.

cone/ side gear and the corresponding side of the

9. Bring the cap and flange sections of the case

differential case with a daub of paint.

together, insert two case bolts in opposite holes

3. Remove the cone/ side gear sub-assembly from

and tighten the bolts evenly to 40Nm.

the flange section of the case.

10. Install the axle shaft, into the flange section of the

4. Remove the differential pinion shaft/ pinion gears/

case.

thrust washers and the pinion shaft locking pin

11. Using Special Tool E6662 check that the torque

from the cap section of the case.

required to continuously rotate the side gears is

5. Remove the remaining cone/ side gear

between 50 and 130Nm.

sub-assembly from the cap section of the case.

12. Remove the tools or axle shaft from the assembly

and install the remaining case bolts.
NOTE: If the tool or axle shaft binds in the spline,

a light tap with a hammer may be necessary.

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