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Tire Diagnosis
Irregular and/or Premature Wear
Irregular and premature wear has many possible causes. Some
of them are: incorrect inflation pressures lack of tire rotation, driv-
ing habits, improper alignment.
If the following conditions are noted rotation is in order:
Front tire wear is different from rear.
Uneven wear exists across the tread of any tire.
Left front and right front tire wear is unequal.
Left rear and right rear tire wear is unequal.
There is cupping, flat spotting, etc.
A wheel alignment check is in order if the following conditions are
noted:
Left front and right front tire wear is unequal.
Wear is uneven across the tread of any front tire.
Front tire treads have scuffed appearance with “feather”
edges on one side of tread ribs or blocks.
Wear Indicators
The original equipment tires have built-in tread wear indicators to
show when tires need replacement. These indicators will appear
as 12 mm (0.47 inch) wide bands when the tire tread depth
becomes 1.6 mm (0.063 inch). When the indicators appear in 3 or
more grooves at 6 locations, tire replacement is recommended.
Radial Tire Waddle
Waddle is side to side movement at the front and/or rear of the
vehicle. It is caused by the steel belt not being straight within the
tire. It is most noticeable at low speed, 5 to 30 mph. It is possible
to road test a vehicle and tell on which end of the vehicle the
faulty tire is located. If the waddle tire is on the rear, the rear end
of the vehicle will shake from side to side or “waddle”. From the
driver’s seat it feels as though someone is pushing on the side of
the vehicle. If the faulty tire is on the front, the waddle is more
visual. The front sheet metal appears to be moving back and forth
and the driver feels as though he is at the pivot point in the vehi-
cle. Waddle can be quickly diagnosed by using a Tire Problem
Detector (TPD) and following the equipment manufacturer’s rec-
ommendations.
If a TPD is not available, the more time consuming method of sub-
stituting known good tire / wheel assemblies on the problem vehi-
cle can be used as follows:
[A] : Hard cornering, under inflation or lack of tire rotation
[B] : Incorrect wheel alignment, tire construction not uniform or wheel heavy acceleration
Downloaded from www.Manualslib.com manuals search engine 3-6 STEERING, SUSPENSION, WHEELS AND TIRES
1) Ride vehicle to determine whether the front or rear waddles.
2) Install tires and wheels that are known to be good (on similar vehicle) in place of those on wadding end of
vehicle. If wadding end cannot be identified, substitute rear ones.
3) Road test again. If improvement is noted, reinstall originals one at a time till waddle causal tire is found. If no
improvement is noted, install known good tires in place of all four. Then reinstall originals in the same man-
ner as above.
EQUIPMENT MANUFACTURE’S RECOMMENDATIONS
INFLATE TIRES TO RECOMMENDED
PRESSURE
ROAD TEST VEHICLE LEVEL
UNCROWNED ROAD IN
BOTH DIRECTIONS
SWITCH FRONT TIRES
SIDE TO SIDE AND
ROAD TEST AGAIN
LEAD CORRECTED IF
ROUGHNESS RESULTS.
REPLACE TIRES
INSTALL A KNOWN GOOD TIRE
ON ONE FRONT SIDE
LEAD REMAING
INSTALL A KNOWN GOOD TIRE IN
PLACE OF OTHER FRONT TIRE
LEAD REMAING
KNOWN GOOD TIRES ARE NOT GOOD
LEAD CORRECTED
REPLACE TIRE
LEAD REVERSES
DIRECTION
PUT TIRES BACK IN
ORIGINAL POSITION
AND CHECK ALIGNMENT
LEAD IN SAME
DIRECTION
LEAD CORRECTED
REPLACE TIRE
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Radial Tire Lead
“Lead” is the deviation of the vehicle from a straight path on a level rod even with no pressure on the steering
wheel.
Lead is usually caused by:
1) Incorrect alignment.
2) Uneven brake adjustment.
3) Tire construction.
The way in which a tire is built can produce lead in a vehicle. An example of this is placement of the belt. Off
center belts on radial tires can cause the tire to develop a side force while rolling straight down the road. If one
side of the tire has a little larger diameter than the other, the tire will tend to roll to one side. This will develop a
side force which can produce vehicle lead.
The procedure in above figure (Lead Diagnosis) should be used to make sure that front alignment is not mis-
taken for tire lead.
1) Part of the lead diagnosis procedure is different from the proper tire rotation pattern currently in the owner
and service manuals. If a medium to high mileage tire is moved to the other side of the vehicle, be sure to
check that ride roughness has not developed.
2) Rear tires will not cause lead.
Vibration Diagnosis
Wheel unbalance causes most of the highway speed vibration problems. If a vibration remains after dynamic
balancing, its possible causes are as follows.
1) Tire runout.
2) Wheel runout.
3) Tire stiffness variation.
Measuring tire and/or wheel free runout will uncover only part of the problem. All three causes, known as loaded
radial runout, must be checked by using a Tire Problem Detector (TPD). If TPD is not available, alternative
method of substituting known good tire and wheel assemblies on the problem vehicle can be used, although it
takes a longer time.
[A] : Tire out of round 1. Smooth road
[B] : Tire stiffness variation 2. Suspension movement (loaded runout)
[C] : Rim bent or out of round
Downloaded from www.Manualslib.com manuals search engine 3A-2 FRONT WHEEL ALIGNMENT
General Description
Front alignment refers to the angular relationship between the
front wheels, the front suspension attaching parts and the ground.
Generally, the only adjustment required for front wheel alignment
is toe setting.
Camber and caster can’t be adjusted. Therefore, should camber
or caster be out of specification due to the damage caused by
hazardous road conditions or collision, whether the damage is in
body or in suspension should be determined. If the body is dam-
aged, it should be repaired and if suspension is damaged, it
should be replaced.
Toe Setting
Toe is the turning in or out of the front wheels. The purpose of a
toe specification is to ensure parallel rolling of the front wheels
(Excessive toe-in or toe-out may increase tire wear).
Toe-in
“B” – “A” : 2 – 6 mm (0.08 – 0.24 in.)
For adjusting toe setting, refer to “Toe Adjustment” in this section.
Camber
Camber is the tilting of the front wheels from the vertical, as
viewed from the front of the vehicle. When the wheels tilt outward
at the top, the camber is positive. When the wheels tilt inward at
the top, the camber is negative. The amount of tilt is measured in
degrees.
Camber
“C” : 0° 30’ ± 1°
Alignment Service Data (Reference)
Caster
: 1° 55’ ± 1° NOTE:
Toe-in value was measured by using a toe-in gauge.
[A]: Wheel top view
1. Forward
“A”
“B”1 [A]
1. Body center [A]: Front view
2. Center line of wheel
2
1
90
o
C [A]
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Diagnosis
Diagnosis Table
For the details, refer to “Diagnosis Table” in Section 3.
Preliminary Checks Prior To Adjusting Front Wheel Alignment
Steering and vibration complaints are not always the result of improper alignment. An additional item to be
checked is the possibility of tire lead due to worn or improperly manufactured tires. “Lead” is the deviation of the
vehicle from a straight path on a level road without hand pressure on the steering wheel. Section 3 of this man-
ual contains a procedure for determining the presence of a tire lead problem. Before making any adjustment
affecting toe setting, the following checks and inspections should be made to ensure correctness of alignment
readings and alignment adjustments:
1) Check all tires for proper inflation pressures and approximately the same tread wear.
2) Check for loose of king pin bearings. Check tie rod ends; if excessive looseness is noted, it must be cor-
rected before adjusting.
3) Check for run-out of wheels and tires.
4) Check vehicle trim heights; if out of limits and a correction is to be made, it must be made before adjusting
toe.
5) Check for loose of suspension arms.
6) Check for loose or missing stabilizer bar attachments.
7) Consideration must be given to excess loads, such as tool boxes. If this excess load is normally carried in
vehicle, it should remain in vehicle during alignment checks.
8) Consider condition of equipment being used to check alignment and follow manufacturer's instructions.
9) Regardless of equipment used to check alignment, vehicle must be on a level surface both fore and aft and
transversely.
Toe Adjustment
Toe is adjusted by changing tie rod length. Loosen right and left
tie rod end lock nuts first and then rotate tie rod to align toe-in to
specification.
In this adjustment, right and left tie rod should become equal in
length (“A”).
After adjustment, tighten lock nuts to specified torque.
Tightening torque
Tie rod end lock nuts
(a) : 65 N·m (6.5 kg-m, 47.0 lb-ft)
Downloaded from www.Manualslib.com manuals search engine 3A-4 FRONT WHEEL ALIGNMENT
Camber And Caster Check And Adjustment
Should camber or caster be found out of specifications upon
inspection, locate its cause first. If it is in damaged, loose, bent,
dented or worn suspension parts and axle housing, they should
be replaced. If it is in vehicle body, repair it so as to attain specifi-
cations.
Steering Angle Check And Adjustment
When tie rod (2) or tie rod end (3) was replaced, check toe and
then also steering angle with turning radius gauge (1).
If steering angle is not correct, check if right and left tie rods are
equal in length “A”.
Steering angle
Inside : 35° ± 3°
Outside : 32° ± 3°
Side Slip(Reference)
For inspecting front wheel side slip with side slip tester:
If side slip exceeds limit, toe or front wheel alignment may out not
be correct.
Side slip limit
: Less than 3 mm/m (Less than 0.118 in/3 ft) NOTE:
To prevent possible incorrect reading of camber or
caster, vehicle front end must be moved up and down a
few times before inspection.
NOTE:
If tie rod lengths were changed to adjust steering angle,
reinspect toe-in.
Downloaded from www.Manualslib.com manuals search engine FRONT SUSPENSION 3D-1
6F1
6F2
6G
1A
6K
7A
7A1
3D
7F
8A
8A
8B
8C
8D
8E
9
10
10A
10B
SECTION 3D
FRONT SUSPENSION
CONTENTS
General Description ....................................... 3D-2
4WD Control System .................................... 3D-2
Diagnosis ........................................................ 3D-8
Diagnosis Table ........................................... 3D-8
4WD Controller and ITS Circuit Check ....... 3D-10
4WD Control System Check ...................... 3D-11
Stabilizer bar / bushing check ................ 3D-13
Shock Absorber and/or Coil Spring
Check ......................................................... 3D-14
Leading Arm / Lateral Rod / Steering
Knuckle Check ........................................... 3D-14
Leading Arm Bushing / Lateral Rod
Bushing Check ........................................... 3D-15
Kingpin / Kingpin Bearing Check ................ 3D-15
Barfield Joint Check ................................... 3D-15
Steering Knuckle Seal Check ..................... 3D-15
Wheel Disc, Nut and Bearing Check .......... 3D-16On-Vehicle Service ...................................... 3D-17
Stabilizer Bar / Bushings ............................ 3D-17
Front Shock Absorber ................................ 3D-19
Coil Spring ................................................. 3D-19
Bump Stopper and Spring Upper Seat ...... 3D-21
Wheel Hub / Bearing / Oil Seal .................. 3D-21
Steering Knuckle / Wheel Spindle.............. 3D-28
Front Axle Shaft / Oil Seal / Kingpin
Bearing Outer Race ................................... 3D-32
Steering Knuckle Seal................................ 3D-34
Lateral Rod ................................................ 3D-35
Leading Arm / Bushing............................... 3D-36
Front Axle Housing .................................... 3D-38
Tightening Torque Specifications .............. 3D-44
Required Service Material ........................... 3D-44
Special Tool .................................................. 3D-45
WARNING:
When hoisting vehicle, be sure to select the lifting point suitable for the service work referring to Sec-
tion 0A.
NOTE:
All front suspension fasteners are an important attaching part in that it could affect the performance
of vital parts and systems, and/or could result in major repair expense. They must be replaced with
one of the same part number or with an equivalent part if replacement becomes necessary. Do not
use a replacement part of lesser quality or substitute design. Torque values must be used as speci-
fied during reassembly to assure proper retention of this part.
Never attempt to heat, quench or straighten any front suspension part. Replace it with a new part or
damage to the part may result.
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General Description
4WD Control System
The 4WD control system consists of a 4WD switch, a vacuum switch, a vacuum tank, two vacuum switching
valves (VSV1 and VSV2) and air locking hub assemblies.
The 4WD controller controls locking or unlocking of the air locking hub according to operation of the transfer shift
control lever.
Vacuum generated in the intake manifold passes through the check valve and stored in the vacuum tank.
According to signals from the 4WD switch, the 4WD controller activates VSV1 (for unlocking) or VSV2 (for lock-
ing) to apply vacuum from the vacuum tank so that the front axle and the wheel hub are disengaged or engaged.
1. Front axle housing 3. Steering knuckle 5. Wheel spindle 7. Wheel bearing
2. Shock absorber 4. Kingpin 6. Wheel hub 8. Front axle shaft (4WD)