Isuzu N-Series. Manual - part 190

FRONT AXLE 4C-55

Inspection and Repair

Make the necessary adjustments, repairs, and part re-
placements if excessive wear or damage is discovered
during inspection.
Front Axle Tube End
Inspect the front axle case tube end sphere for crack,
wear, damage or rust. Slight rust of sphere should be
polished with a sand paper.
To check the tube end sphere for crack, use a red-check
or a magnetic flaw detector.
If a crack is found, replace the front axle case assembly.

Front Axle Knuckle
Inspect the whole of the knuckle for cracks, wear or
damage using a magnetic flaw detector or red-check.
Replace the knuckle if any abnormal condition is notice-
able.

King Pin
Inspect the king pin for cracks.
Use a magnetic flaw detector or red-check.
Replace king pin, if any cracks are found.

King Pin Bearing
Inspect the bearing for wear, seizure, damage and
rough rotation.
Replace any flawed or damaged bearing.

Knuckle Arm
Tie Rod Arm
King Pin Cover
Inspect the knuckle arm, tie rod arm and king pin cover
for cracks, damage or wear.
Replace the these parts if any abnormal condition is
noticeable.
To check the arm for crack, use a visible dye-penetrant
flaw detection method or a magnetic flaw detector.
Replace the arm if a crack is found.

Front Axle Tube End Boot
Inspect the front axle tube end boot and replace if
broken. It should be replaced if even one hole or crack is
found.
Oil Seal
Inspect the oil seal, and replace it if its lip is damaged,
worn or hardened.

N4A0376E

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N4A0378E

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4C-56 FRONT AXLE

Front Axle Tube End Boot Holder, Oil Seal Holder
Inspect the oil seal holder and front axle tube end boot
holder, and replace if excessive deformation or rust is
found.

Installation

1. Front Axle Shaft Oil Seal

1) Drive in the oil seal to the dimension as shown.

Take care not to damage the oil seal lip.

2) Apply grease (Multipurpose type) to the oil seal

lip.

Oil seal drive in depth (L): 0 — 0.5 mm (0 — 0.020 in)

2. Front Axle Tube End Boot Holder
3. Front Axle Tube End Boot

1) Apply gear oil GL-5 grade (SAE90) to the entire

surface of front axle tube end sphere.

2) Warm the front axle tube end boot to 70 —

80

°C with hot water.

3) Reverse the front axle tube end boot, and in-

stall into the front axle case. During this work,
do not touch the front axle tube end boot by
bear hand because it is too hot.

4) After installation in the front axle case, remove

the moisture immediately.

5) Return the front axle tube end boot to original

form, and insert the leading end of boot into the
front axle tube end boot groove of the front axle
case.

4. Knuckle Oil Seal
5. Front Axle Tube End Boot Band

1) Fix the boot with front axle tube end boot band.

Wind the front axle tube end boot band twice
and tighten it up to eliminate looseness.

2) Then, calk the center of fitting on the front axle

tube end boot band with a punch.

3) Turn back the front axle tube end boot band at

the fitting, and again calk the center of front
axle tube end boot band.

4) Cut the front axle tube end boot band at the end

face of fitting.

N4A0380E

N4A0390E

N4A0391E

FRONT AXLE 4C-57

Install the oil seal to the front axle. (Apply Multipur-
pose type grease, to the entire surface of oil seal,
and install it with care not to damage the oil seal lip.
In installing the oil seal, position the spring side on
the differential side.)

6. Front Axle Upper King Pin
7. Front Axle Lower King Pin

1) Seal multi-purpose grease NLGI No.2 in the

king pin bearing.

2) Install only the king pins (both upper and lower)

in the front axle case.

3) Align the locking groove of the king pin with the

locking pin on the front axle tube end surface,
and then drive in the king pin.

8. King Pin Receiver
9. King Pin Bearing

Install the king pin bearing to the king pin. For the
upper side, install the receiver, king pin bearing in
this order.

10. Front Axle Knuckle

1) Install the knuckle to the front axle. (Holding the

knuckle with both hands, align the upper hole of
knuckle to the upper king pin bearing and lower
it slowly while passing the lower king pin bear-
ing.)

2) Install upper and lower king pin bearing outer

races. (Fit the king pin bearing outer race com-
pletely with the knuckle, and hit lightly the outer
race until it gets stuck.)

11. Bearing Distance Collar
12. King Pin Bearing Shim
13. King Pin Cover
14. Knuckle Arm and Tie Rod Arm

Legend

1. Bend
2. Calking point
3. Punch
4. Front axle tube end boot
5. Fitting

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N4A0393E

N4A0394E

4C-58 FRONT AXLE

1) Install the knuckle arm (or tie rod arm) and the

king pin cover. (Install the distance collar and
shim in this order. Then, install knuckle arm (or
tie rod arm) and the king pin cover and fix pro-
visionally with bolts. Use the number of shims
that were removed previously, and tighten the
bolts lightly. At this time, do not apply LOCTITE
to the shims, arms and king pin cover yet.

2) Tighten the bolts on knuckle arm (or tie rod

arm) and king pin cover to the specified torque
while turning the knuckle to the left and right
several times to run-in the king pin bearing.

Tighten:
Knuckle arm, tie rod arm and king pin cover bolt to147
N

⋅m (15 kg⋅m / 108 lb⋅ft)

<Adjustment of Front Axle Knuckle Preload>

1) Hook a spring balance to the edge of knuckle

arm (or tie rod arm), and pull it in tangential di-
rection to check if the spring balance reading at
the start of movement is within the standard
range. 
(Measure preload in tangential direction.)

Front axle knuckle preload, 3.1 — 5.5 N (6.8 — 12.1 kg
/ 30.4 — 53.9 lb)

2) If it does not satisfy the standard, adjust with

shims.

Shim thickness available: 0.3 mm (0.01 in)

3) After adjustment, measure the preload again.

<Tighten completely the knuckle arm (or tie rod arm)
and king pin cover>

1) Remove each arm and king pin cover once,

and apply adhesive (LOCTITE 515 or equiva-
lent) to the shims, each arm and king pin cover
evenly.

2) Tighten fixing bolts to the specified torque.

Tighten:
Knuckle arm, tie rod arm and king pin cover bolt to147
N

⋅m (15 kg⋅m / 108 lb⋅ft)

3) Reconfirm the preload.

If it is out of standard, readjust by repeating the
above steps.

15. Knuckle Oil Seal

1) Install the inner oil seal holder to the knuckle. 

Install the inner oil seal holder in longitudinal di-
rection.

2) Install the oil seal, then the outer oil seal holder.

Install the outer oil seal holder in vertical direc-
tion (a mating face should be shifted 90

°

against the inner holder).

16. Front Axle Tube End Boot
17. Front Axle Tube End Boot Holder

Install the front axle tube end boot, and tighten
bolts to the specified torque via the front axle tube
end boot holder.
Install the front axle tube end boot holder in longi-
tudinal direction.

Tighten:
Front axle tube end boot holder bolt to 6 N

⋅m (0.6 kg⋅m

/ 52 lb

⋅ft)

N4A0395E

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