Install head bolts. Head bolts should be tightened in proper
steps and sequence to specification. See Fig. 1. Install remaining
components. Tighten all bolts to specification. Adjust valves if
required. See VALVE ADJUSTMENT in this article.
NOTE: Some manufacturers require that head bolts be retightened
after specified amount of operation. This must be done to
prevent head gasket failure.
VALVE ADJUSTMENT
Engine specifications will indicate valve train clearance and
temperature at which adjustment is to be made on most models. In most
cases, adjustment will be made with a cold engine. In some cases, both
a cold and a hot clearance will be given for maintenance convenience.
On some models, adjustment is not required. Rocker arms are
tightened to specification and valve lash is automatically set. On
some models with push rod actuated valve train, adjustment is made at
push rod end of rocker arm while other models do not require
adjustment.
Clearance will be checked between tip of rocker arm and tip
of valve stem in proper sequence using a feeler gauge. Adjustment is
made by rotating adjusting screw until proper clearance is obtained.
Lock nut is then tightened. Engine will be rotated to obtain all valve
adjustments to manufacturer's specifications.
Some models require hydraulic lifter to be bled down and
clearance measured. Different length push rods can be used to obtain
proper clearance. Clearance will be checked between tip of rocker arm
and tip of valve stem in proper sequence using a feeler gauge.
On overhead cam engines designed without rocker arms actuate
valves directly on a cam follower. A hardened, removable disc is
installed between the cam lobe and lifter. Clearance will be checked
between cam heel and adjusting disc in proper sequence using a feeler
gauge. Engine will be rotated to obtain all valve adjustments.
On overhead cam engines designed with rocker arms, adjustment
is made at push rod end of rocker arm. Ensure that the valve to be
adjusted is riding on the heel of the cam on all engines. Clearance
will be checked between tip of rocker arm and tip of valve stem in
proper sequence using a feeler gauge. Adjustment is made by rotating
adjusting screw until proper clearance is obtained. Lock nut is then
tightened. Engine will be rotated to obtain all valve adjustments to
manufacturer's specifications.
CYLINDER HEAD OVERHAUL
* PLEASE READ THIS FIRST *
NOTE: Always refer to appropriate engine overhaul article in the
ENGINES section for complete overhaul procedures and
specifications for the vehicle being repaired.
DISASSEMBLY
Mark valves for location. Using valve spring compressor,
compress valve springs. Remove valve locks. Carefully release spring
compressor. Remove retainer or rotator, valve spring, spring seat and
valve. See Fig. 2.
ROCKER ARMS & ASSEMBLIES
Rocker Studs
Rocker studs are either threaded or pressed in place.
Threaded studs are removed by locking 2 nuts on the stud. Unscrew the
stud by turning the jam nut. Coat the stud threads with Loctite and
install. Tighten to specification.
Pressed in stud can be removed using a stud puller. Ream the
stud bore to proper specification and press in a new oversize stud.
Pressed in studs are often replaced by cutting threads in the stud
bore to accept a threaded stud.
Rocker Arms & Shafts
Mark rocker arms for location. Remove rocker arm retaining
bolts. Remove rocker arms. Inspect rocker arms, shafts, bushings and
pivot balls (if equipped) for excessive wear. Inspect rocker arms
for wear in valve stem contact area. Measure rocker arm bushing I.D.
Replace bushings if excessively worn.
The rocker arm valve stem contact point can be reground,
using special fixture for valve grinding machine. Remove minimum
amount of material as possible. Ensure all oil passages are clear.
Install rocker arms in original locations. Ensure rocker arm is
properly seated in push rod. Tighten bolts to specification. Adjust
valves if required. See VALVE ADJUSTMENT in this article.
Pushrods
Remove rocker arms. Mark push rods for location. Remove push
rods. Push rods can be steel or aluminum, solid or hollow. Hollow
pushrods must be internally cleaned to ensure oil passage to the
rocker arms is cleaned. Check the pushrod for damage, such as loose
ends on steel tipped aluminum types.
Check push rod for straightness. Roll push rod on a flat
surface. Using feeler gauge, check clearance at center. Replace push
rod if bent. The push rod can also be supported at each end and
rotated. A dial indicator is used to detect bends in the push rod.
Lubricate ends of push rod and install push rod in original
location. Ensure push rod is properly seated in lifter. Install rocker
arm. Tighten bolts to specification. Adjust valves if required. See
VALVE ADJUSTMENT in this article.
LIFTERS
Hydraulic Lifters
Before replacing a hydraulic lifter for noisy operation,
ensure noise is not caused by worn rocker arms or valve tips.
Hydraulic lifter assemblies must be installed in original locations.
Remove the rocker arm assembly and push rod. Mark components for
location. Some applications require intake manifold, or lifter cover
removal. Remove lifter retainer plate (if used). To remove lifters,
use a hydraulic lifter remover or magnet. Different type lifters are
used. See Fig. 13.
Engine pre-oiling can be done using pressure oiler (if
available). Connect pressure oiler to cylinder block oil passage
such as oil pressure sending unit. Operate pressure oiler long enough
to ensure correct amount of oil has filled crankcase. Check oil level
while pre-oiling.
If pressure oiler is not available, disconnect ignition
system. Remove oil pressure sending unit and replace with oil pressure
test gauge. Using starter motor, rotate engine starter until gauge
shows normal oil pressure for several seconds. DO NOT crank engine
for more than 30 seconds to avoid starter motor damage.
Ensure oil pressure has reached the most distant point from
the oil pump. Reinstall oil pressure sending unit. Reconnect ignition
system.
INITIAL START-UP
Start the engine and operate engine at low speed while
checking for coolant, fuel and oil leaks. Stop engine. Recheck coolant
and oil level. Adjust if necessary.
CAMSHAFT
Break-in procedure is required when a new or reground
camshaft has been installed. Operate and maintain engine speed between
1500-2500 RPM for approximately 30 minutes. Procedure may vary due to
manufacturers recommendations.
PISTON RINGS
Piston rings require a break-in procedure to ensure seating
of rings to cylinder walls. Serious damage may occur to rings if
correct procedures are not followed.
Extremely high piston ring temperatures are produced obtained
during break-in process. If rings are exposed to excessively high RPM
or high cylinder pressures, ring damage can occur. Follow piston ring
manufacturer's recommended break-in procedure.
FINAL ADJUSTMENTS
Check or adjust ignition timing and dwell (if applicable).
Adjust valves (if necessary). Adjust carburetion or injection idle
speed and mixture. Retighten cylinder heads (if required). If
cylinder head or block is aluminum, retighten bolts when engine is
cold. Follow the engine manufacturer's recommended break-in procedure
and maintenance schedule for new engines.
NOTE: Some manufacturer's require that head bolts be retightened
after specified amount of operation. This must be done to
prevent head gasket failure.
1) Using Socket (MB990954) and torque wrench, rotate front
hub and tighten lock nut to 95-145 ft. lbs. (129-197 N.m) to seat
bearings. Loosen nut. Retighten nut to 18 ft. lbs. (24 N.m) and loosen\
30-40 degrees.
2) Using spring scale attached to wheel stud, measure and
record turning resistance required to rotate hub/rotor assembly before
installing locking hub.
3) Apply semi-drying sealant on locking hub assembly-to-
hub/rotor contact areas. DO NOT apply sealant on outer areas of
hub/rotor assembly, toward brake contact areas.
4) Align locking hub assembly key area with steering knuckle
keyway area. Loosely install locking hub assembly on hub/rotor
assembly. Ensure locking hub assembly fully contacts hub/rotor
assembly.
5) Install locking hub retaining bolts. Tighten to
specification. See TORQUE SPECIFICATIONS table at end of article.
Using spring scale attached to wheel stud, measure turning resistance
required to rotate hub/rotor assembly.
6) Subtract turning resistance measured in step 2) (before
installing locking hub) from turning resistance measured in step 5)
(after installing locking hub). If difference exceeds 3.1 lbs. (14 N)\
,
check for incorrect installation of locking hub assembly or
components.
7) Install shim and snap ring on drive axle. Rotate drive
axle until maximum end play is obtained. Using dial indicator, check
drive axle end play.
8) Drive axle end play should be .008-.020" (.20-.51 mm). If\
end play is not within specification, adjust drive axle end play by
changing axle shaft shim. Install new "O" ring and cover. Tighten
cover to specification. See TORQUE SPECIFICATIONS table at end of
article.
LOWER CONTROL ARM R & I
REMOVAL
1) Raise and support vehicle. Remove wheel assembly. Remove
front skid plate and undercover (if equipped). Remove torsion bar. See\
TORSION BAR under REMOVAL & INSTALLATION. Remove stabilizer bar bolt
from control arm.
2) Remove shock absorber-to-control arm bolts. Loosen but DO
NOT remove lower ball joint-to-steering knuckle nut. Using ball joint
fork, separate lower ball joint from steering knuckle.
3) Remove ball joint stud nut from steering knuckle. Remove
control arm shaft. See Fig. 1. Remove torque arm. Remove lower control
arm pivot bolt. Remove lower control arm.
INSPECTION
1) Inspect control arm for cracks or deformation. Check ball
joints. See BALL JOINT CHECKING under ADJUSTMENTS & INSPECTION.
2) Inspect ball joint dust covers for damage. Replace dust
covers if damaged. Inspect control arm bushing and frame bracket
bushing for damage. Replace if necessary.
3) If frame bracket bushing needs replacing, install Bushing
Remover/Installer (MB990958-01) in bushing. See Fig. 3. Tighten
bushing remover/installer bolt until bushing is removed. Reverse
bushing remover/installer to install bushing.
NOTE: Differential carrier may require relocation to replace left
bracket bushing.
shaft.
3) On Montero, install control arm-to-crossmember bolts from
the outside of control arm, with nuts against crossmember.
4) Ensure alignment shims are placed in original location.
When installing shock absorber, ensure White paint mark on lower end
of shock faces toward the outside of vehicle. Tighten shock absorber
upper nut until distance from end of threads to nut is .27-.31" (7-8
mm). Install shock lock nut.
5) Tighten bolts to specification. See TORQUE SPECIFICATIONS
table at end of article. Bleed brakes. Adjust anchor bolt to proper
torsion bar setting. See TORSION BAR under REMOVAL & INSTALLATION.
Check wheel alignment and adjust if necessary.
WHEEL BEARINGS R & I
REMOVAL
1) Raise and support vehicle. Remove wheel assembly. Remove
caliper assembly. Remove locking hub. See LOCKING HUB under REMOVAL &
INSTALLATION.
2) Remove lock washer. Using Socket (MB990954), remove lock
nut. Remove front hub assembly from steering knuckle.
3) Remove oil seal and bearings from hub. If bearing races
need to be replaced, drive bearing races from hub using brass drift
and hammer.
INSTALLATION
1) Before installing, lubricate outside surfaces of bearing
outer races with grease. Install bearing outer races in hub. Ensure
bearing races are fully seated.
2) Pack bearings with grease. Install inner bearing in hub.
On Montero, install seal in hub using Seal Installer (MB990955). On
Pickup, use Seal Installer (MB990985).
3) Install seal until seal is even with hub surface. To
complete installation, reverse removal procedure. Adjust wheel
bearings. See WHEEL BEARINGS under ADJUSTMENTS & INSPECTION. Tighten
bolts to specification. See TORQUE SPECIFICATIONS table.
TORQUE SPECIFICATIONS
TORQUE SPECIFICATIONS TABLE \
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Application Ft. Lbs. (N.m)
Anchor Bolt Lock Nut ............. 29-36 (39-49)
Automatic Hub Cover .............. 13-25 (18-34)
Ball Joint Nut
Lower ....................... 87-130 (118-176)
Upper .......................... 43-65 (58-88)
Ball Joint-to-Lower
Control Arm Bolt ............... 39-54 (53-73)
Caliper Bolt ..................... 58-72 (79-98)
Control Arm-to-Frame Bolt
Lower ................. ( 1) 101-116 (137-157)
Upper ......................... 72-87 (98-118)
Locking Hub-to-Hub/Rotor Bolt .... 36-43 (49-58)
Manual Hub Cover Bolt .................. 10 (14)
Shock Absorber Lower Mount Bolt
Montero ........................ 11-16 (15-22)
Ram-50 & Pickup ...................... 10 (14)
Worn or dirty needle valve Clean carburetor, see
and seat ENGINE PERFORMANCE
Float sticking Readjust or replace
float see the ENGINE
PERFORMANCE section
Incorrect choke adjustment Reset choke adjustment
see ENGINE PERFORMANCE
Defective coil Replace coil
Improper spark plug gap Regap spark plugs
Incorrect ignition timing Reset ignition timing
see ENGINE PERFORMANCE
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Detonation Over-advanced ignition Reset ignition timing
timing see ENGINE PERFORMANCE
Defective spark plugs Replace spark plugs
Fuel lines clogged Clean fuel lines
EGR system malfunction Check and repair EGR
system
PCV system malfunction Repair PCV system
Vacuum leaks Check and repair
vacuum system
Loose fan belts Tighten or replace
fan belts, see ENGINE
PERFORMANCE
Restricted airflow Remove restriction
Vacuum advance malfunction Check distributor
operation
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Dieseling Binding carburetor linkage Eliminate binding
Binding throttle linkage Eliminate blinding
Binding choke linkage or Eliminate binding
fast idle cam
Defective idle solenoid Replace idle solenoid
see ENGINE PERFORMANCE
Improper base idle speed Reset idle speed, see
see ENGINE PERFORMANCE
Incorrect ignition timing Reset ignition timing
see ENGINE PERFORMANCE
Incorrect idle mixture Reset idle mixture,
setting see ENGINE PERFORMANCE
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Faulty Incorrect ignition timing Reset ignition timing
Acceleration see ENGINE PERFORMANCE
setting, see ENGINE
PERFORMANCE
Vacuum leak Eliminate vacuum leak
EGR valve malfunction Replace EGR valve
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Poor Gasoline Cracked or broken vacuum Replace vacuum hoses
Mileage hoses
Vacuum leaks Repair vacuum leaks
Defective ignition wires Replace wires
Incorrect choke setting Readjust setting, see
ENGINE PERFORMANCE
Defective vacuum advance Replace vacuum advance
Defective spark plugs Replace spark plugs
Binding carburetor power Eliminate binding
piston
Dirt in carburetor jets Clean and/or replace
jets
Incorrect float adjustment Readjust float
setting, see FUEL
Defective power valve Replace power valve,
see ENGINE PERFORMANCE
Incorrect idle speed Readjust idle speed
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Engine Stalls Improper float level Readjust float level
Leaking needle valve and Replace needle valve
seat and seat
Vacuum leaks Eliminate vacuum
leaks
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VACUUM PUMP - DIESEL TROUBLE SHOOTING
NOTE: This is GENERAL information. This article is not intended
to be specific to any unique situation or individual vehicle
configuration. The purpose of this Trouble Shooting
information is to provide a list of common causes to
problem symptoms. For model-specific Trouble Shooting,
refer to SUBJECT, DIAGNOSTIC, or TESTING articles available
in the section(s) you are accessing.
NOTE: Diesel engines mechanical diagnosis is the same as gasoline
engines for items such as noisy valves, bearings, pistons,
etc. The following trouble shooting covers only items
pertaining to diesel engines.
VACUUM PUMP (DIESEL) TROUBLE SHOOTING CHART
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CONDITION POSSIBLE CAUSE CORRECTION \
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Column not correctly See STEERING COLUMNS
aligned article
Broken lower joint Replace joint
Horn contact ring not See STEERING COLUMN
article
Bearing not lubricated See STEERING COLUMN
article
Shaft snap ring not Reseat or replace snap
properly seated ring
Plastic spherical joint See STEERING COLUMN
not lubricated article
Shroud or housing loose Tighten holding screws
Lock plate retaining See STEERING COLUMN
ring not seated article
Loose sight shield Tighten holding screws
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High Steering Column assembly See STEERING COLUMN
Shaft Effort misaligned article
Improperly installed dust Adjust or replace
shield
Tight steering universal See STEERING COLUMN
joint article
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High Shift Column is out of See STEERING COLUMN
Effort alignment article
Improperly installed Adjust or replace
dust shield
Seals or bearings not See STEERING COLUMNS
lubricated article
Mounting bracket screws Replace with new
too long shorter screws
Burrs on shift tube Remove burrs or replace
tube
Lower bowl bearing See STEERING COLUMN
assembled wrong article
Shift tube bent or broken Replace as necessary
Improper adjustment of See STEERING COLUMN
shift levers article
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Improper Trans. Sheared shift tube joint Replace as necessary
Shifting
Sheared lower shaft lever Replace as necessary
Improper shift lever See STEERING COLUMN
adjustment article