1991 MITSUBISHI MONTERO front main seal

TIMING BELT under REMOVAL & INSTALLATION. Remove intake camshaft
sprockets.
4) Remove coolant manifold and coolant inlet pipe. Using
Socket (MD998051), remove cylinder head bolts. Remove cylinder head
and camshaft assemblies. Note direction of washer installation on head
bolts.
Inspection (DOHC)
Check cylinder head height. Check warpage at gasket and
manifold surfaces. Resurface head if warpage exceeds specification.
See CYLINDER HEAD (DOHC) table under ENGINE SPECIFICATIONS at end of
article. After resurfacing, recheck cylinder head height. Replace
cylinder head if it is not within specification.
Installation (DOHC)
1) Ensure mating surfaces are clean and dry. Note
identification mark located on front of head gasket. Identification
marks are: "R" for SOHC, "2DN" for DOHC non-turbocharged and "2DT" for
DOHC turbocharged engine. Install head gasket with identification mark
toward timing belt side of engine and facing upward. Ensure all holes
are aligned.
NOTE: Install head gasket with identification mark toward timing
belt side of engine and facing upward. Ensure all holes
align. Install washers on head bolts with chamfered side
toward bolt head.
2) Install cylinder head and bolts. Ensure washers are
installed on head bolts with chamfered side toward bolt head. Using
proper sequence, tighten bolts to specification in 2-3 steps. See
Fig. 5 . See TORQUE SPECIFICATIONS (3000GT) table at end of article. On
turbocharger equipped engines, back off head bolts once, and repeat
tightening procedure.
3) To reinstall camshaft sprocket, hold hexagonal area of
camshaft using wrench while tightening sprocket bolt. Tighten rocker
cover bolts in a crisscross pattern. Start at 4 corners of rocker
cover and move toward center.
NOTE: Rocker cover bolts are color coded. Front cylinder bank
bolts are black; rear cylinder bank bolts are green.
4) To complete installation, reverse removal procedure.
Tighten bolts and nuts to specification. See TORQUE SPECIFICATIONS
(3000GT) table.
FRONT CRANKSHAFT OIL SEAL
Removal & Installation
Remove timing belt and crankshaft sprocket. See TIMING BELT
under REMOVAL & INSTALLATION. Pry oil seal from oil pump. To install,
coat seal lip with grease. Using Seal Installer (MD998717), install
seal in oil pump. Install remaining components. See appropriate TORQUE
SPECIFICATIONS table at end of article.
TIMING BELT
Removal (Montero & Pickup)
1) Drain cooling system. Disconnect upper radiator hose.
Remove upper radiator shroud. Remove cooling fan and fan clutch
assembly. Remove cooling fan pulley. Remove all drive belts. Remove
power steering pump with pressure and return hoses connected, and set
aside.
2) Remove power steering pump brackets. Remove A/C tensioner

Install valve lash adjusters and valve lash adjuster holders (if
removed). See Fig. 18.
2) Apply 3M Sealant (4171) to designated areas of cylinder
head. See Fig. 19. Use care so sealant does not get on camshaft or
camshaft bearing journals. Install rocker arm assembly. Ensure arrow
on bearing cap faces same direction as arrow on cylinder head. See
Fig. 19 . Tighten bearing cap bolts to specification. See appropriate
TORQUE SPECIFICATIONS table at end of article. Remove valve lash
adjuster holders.
3) Coat camshaft oil seal area with oil. Using Seal Installer
(MD998713), install camshaft oil seal. Using Circular Packing
Installer (MD998306), install circular packing to press-in depth of .
02" (.5 mm).
4) Apply Three Bond (1212D) sealant to rocker cover sealing
surfaces before installation. See Fig. 6. Coat new "O" ring with oil,
and install on distributor adapter (if removed).
5) Coat camshaft area with oil before installing distributor
adapter. To complete installation, reverse removal procedure. Tighten
bolts to specification. See appropriate TORQUE SPECIFICATIONS table.
Removal (DOHC)
1) Remove UPPER INTAKE MANIFOLD and LOWER INTAKE MANIFOLD as
necessary. See UPPER INTAKE MANIFOLD and LOWER INTAKE MANIFOLD under
REMOVAL & INSTALLATION. Remove timing belt, camshaft sprockets and
rear timing belt covers. See TIMING BELT under REMOVAL & INSTALLATION.
2) Remove center cover and spark plug wires. Remove PCV and
breather hoses. Remove rocker covers and gaskets. Remove crank angle
sensor adapter. Remove front and rear camshaft bearing caps along with
seals and circular packings.
3) Remove remaining camshaft bearing caps in sequence: No. 2,
No. 4 and No. 3. Remove camshaft, rocker arms and lash adjusters. Mark
component location for reassembly reference.
Inspection (DOHC)
Inspect rocker arm for damaged roller and flaking. Inspect
camshaft for damage. Measure camshaft end play, journal diameter and
lobe height. Replace camshaft if it is not within specification. See
CAMSHAFT (DOHC) table in ENGINE SPECIFICATIONS at end of article.
Installation (DOHC)
1) Coat components with oil. Install lash adjusters and
rocker arms. Bring No. 1 cylinder to TDC. Ensure intake and exhaust
camshafts are installed correctly. Intake camshaft is marked with a
"V" and exhaust camshaft is marked with a "C" on hexagon section.
Position camshaft dowels as shown. See Fig. 21.
NOTE: If cylinder head is off vehicle, support cylinder head at
least .39" (10 mm) above work surface to prevent valve
damage while installing camshaft bearing caps.
Fig. 21: Installing Camshafts & Bearing Caps (DOHC)
Courtesy of Mitsubishi Motor Sales of America, Inc.
2) Install camshaft bearing caps in sequence: No. 3, No. 4

Measure cylinder bore and piston skirt diameter. Piston skirt
diameter should be measured at 90-degree angle to piston pin.
Clearance between piston and cylinder bore must be within
specification. See appropriate PISTONS, PINS & RINGS table under
ENGINE SPECIFICATIONS at end of article.
PISTON PIN REPLACEMENT
1) Note reference mark on top of piston and connecting rod.
See Fig. 23 . Using press and Piston Pin Remover/Installer (MD998184
for SOHC or MD998765 for DOHC), remove pin.
2) Inspect piston for cracks and damage. Check ring side
clearance. Replace piston if not within specification. See appropriate
PISTONS, PINS & RINGS table under ENGINE SPECIFICATIONS.
3) Check connecting rod for bend and twist. Replace
connecting rod if twist exceeds .004" (.10 mm) or bend exceeds .002"
(.05 mm). Pressure required to install pin in rod is 1686-3934 lbs.
(7500-17,500 N).
4) Position piston on connecting rod. Ensure reference marks
on top of piston and connecting rod are aligned. See Fig. 23.
Lubricate all components with oil. To install, reverse removal
procedure. Ensure piston pin is centered in piston.
NOTE: Install piston with reference mark aligned with connecting
rod reference mark. See Fig. 23.
CRANKSHAFT & MAIN BEARINGS
1) Remove flywheel or drive plate. Remove
transaxle/transmission mounting plate and rear seal case. Remove oil
pump, oil pan and oil pick-up tube. Ensure connecting rods and main
bearing cap are marked for location.
2) Remove connecting rod caps and bearings. Note direction of
arrow on main bearing cap. Remove main bearing cap. See Fig. 24.
Ensure all components are placed in correct order. Remove crankshaft.
Remove main bearings from cylinder block. Mark bearings for location.
3) Inspect crankshaft for cracks and damaged gear or threads.
Check crankshaft for taper and out-of-round. Replace or repair
crankshaft if it is not within specification. See CRANKSHAFT, MAIN &
CONNECTING ROD BEARINGS table under ENGINE SPECIFICATIONS at end of
article.
4) Install upper main bearings in cylinder block. Ensure oil
hole is aligned and bearing is properly seated. Lubricate bearings
with engine oil. Install thrust bearings on No. 3 main bearing journal
with oil grooves toward crankshaft thrust surface.
5) Install crankshaft in block. Install thrust bearing on No.
3 main bearing cap with oil grooves toward crankshaft thrust surface.
Install main bearing cap with arrow toward front of engine.
6) Check oil clearance using Plastigage method. Tighten bolts
to specification in proper sequence. See Fig. 24. See appropriate
TORQUE SPECIFICATIONS table at end of article. Remove main bearing
cap. Clearance must be within specification. See CRANKSHAFT, MAIN &
CONNECTING ROD BEARINGS table. If oil clearance exceeds specification,
replace bearings or crankshaft.
7) Ensure crankshaft rotates freely with main bearing cap
installed. Check crankshaft end play. See CRANKSHAFT, MAIN &
CONNECTING ROD BEARINGS table.
8) Install connecting rod caps and bearings. Ensure
components are installed in original location. Tighten rod nuts to
specification. See appropriate TORQUE SPECIFICATIONS table. Ensure
connecting rods move freely on crankshaft. To complete installation,
reverse removal procedure. Tighten bolts to specification.

CAUTION: Always replace circlips on BJ splines of left drive axle
and splines of inner shaft.
INSTALLATION
1) Install right drive axle on inner shaft. Install new
circlip on BJ side of left drive axle. Drive left drive axle into
differential. Use care not to damage oil seal.
2) Reinstall knuckle with front hub assembly. If drive axle
end play requires adjustment, select proper shim to obtain proper end
play. Shim is located behind snap ring on end of drive axle. Install
shim and recheck axle end play. Install remaining components in
reverse of removal procedure.
DIFFERENTIAL CARRIER R & I
REMOVAL
1) Raise and support vehicle. Drain gear oil. Support
differential carrier. Remove drive axles and inner shaft. See DRIVE
AXLES R & I and INNER SHAFT & BEARING R & I in this article. Place
alignment mark on drive shaft and pinion flange for reassembly
reference.
2) Remove drive shaft. Remove differential mounting brackets
at differential and frame. See Fig. 1. Disconnect front crossmember
from frame. Remove differential carrier assembly and front
crossmember. Remove differential carrier from front crossmember.
INSTALLATION
To install, reverse removal procedure. Align marks on drive
shaft and pinion flange.

1) Install drive pinion in differential carrier. Install
spacer, pinion front shim(s) and front pinion bearing. DO NOT install
oil seal at this time. Install pinion flange, washer and retaining
nut. Check pinion rotating torque without pinion oil seal.
2) Recheck rotating torque. Rotating torque must be within
specification. See PINION ROTATING TORQUE SPECIFICATIONS table. Adjust
rotating torque by replacing drive pinion front shims or spacer. Once
correct rotating torque is obtained, install oil seal. Coat seal lip
with grease.
3) Install pinion flange so alignment marks are correct.
Apply light coat of grease to flange washer contact area. Install new
retaining nut. Check pinion rotating torque with pinion oil seal
installed. Rotating torque must be within specification. See PINION
ROTATING TORQUE SPECIFICATIONS table.
SIDE BEARING
1) Using Bearing Installer (MB990802-01), install bearings o\
n
differential case. Select 2 side bearing adjusting shims thinner than
those removed. Shims must be equal thickness on both sides. Install
shims on each side of case assembly. Install case assembly in
differential carrier.
2) Push case assembly fully to one side of carrier. Using 2
feeler gauges, measure clearance between carrier and side bearing shim
at opposite sides of bearing. Remove shims from one side of
differential carrier.
3) Measure thickness of shims removed. Add removed shim
thickness and 1/2 of feeler gauge clearance measurement plus .002" (.
05 mm). This is thickness of shim that should be installed on each
side of case. Select proper shims. Install equal shims on each side of
case assembly.
NOTE: Ensure no clearance exists between gear carrier and
adjusting shim.
4) Install side bearing shims and differential case assembly
in differential carrier. Using brass drift, tap shims to fit them to
side bearing outer race. Install bearing caps. Check ring gear
backlash.
RING GEAR BACKLASH
1) Lock drive pinion in place. Using dial indicator, check
ring gear backlash at heel of ring gear tooth. Measure at 4 locations
of ring gear. Gear backlash must be within .004-.006" (.10-.15 mm).
2) If not within specification, change side bearing adjusting
shims and recheck backlash. If backlash is too small, install thinner
shim behind ring gear and thicker shim opposite ring gear.
3) If backlash is excessive, install thicker shim behind ring
gear and thinner shim opposite ring gear. Check gear tooth contact
using paint impression method.
CAUTION: When changing shims, total thickness of all shims must
remain constant.
RING GEAR RUNOUT
Using dial indicator, measure runout at back side of ring
gear. Runout must be within .002" (.05 mm). If runout is excessive,
change ring gear-to-differential case mounting position. Recheck
runout. Install cover and gasket.

CRANKSHAFT & MAIN BEARINGS
* 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.
REMOVAL
Ensure all main bearing caps are marked for location on
cylinder block. Some main bearing caps have an arrow stamped on it
which must face front of engine. Remove main bearing cap bolts. Remove
main bearing caps. Carefully remove crankshaft. Use care not to bind
crankshaft in cylinder block during removal.
CLEANING & INSPECTION
Thoroughly clean crankshaft using solvent. Dry with
compressed air. Ensure all oil passages are clear and free of sludge,
rust, dirt, and metal chips.
Inspect crankshaft for scoring and nicks. Inspect crankshaft
for cracks using Magnaflux procedure. Inspect rear seal area for
grooving or damage. Inspect bolt hole threads for damage. If pilot
bearing or bushing is used, check pilot bearing or bushing fit in
crankshaft. Inspect crankshaft gear for damaged or cracked teeth.
Replace gear if damaged. Check that oil passage plugs are tight (if
equipped).
Using micrometer, measure all journals in 4 areas to
determine journal taper, out-of-round and undersize. See Fig. 20.
Some crankshafts can be reground to the next largest undersize,
depending on the amount of wear or damage. Crankshafts with rolled
fillet cannot be reground and must be replaced.
Fig. 20: Measuring Crankshaft Journal - Typical
This Graphic For General Information Only
Crankshaft journal runout should be checked. Install
crankshaft in "V" blocks or bench center. Position dial indicator

length of cylinder block at several points.
If warpage exceeds specifications, deck must be resurfaced.
If warpage exceeds manufacturer's maximum tolerance for material
removal, replace block.
DECK HEIGHT
Distance from the crankshaft centerline to the block
deck is termed the deck height. Measure and record front and rear main
journals of crankshaft. To compute this distance, install crankshaft
and retain with center main bearing and cap only. Measure distance
from the crankshaft journal to the block deck, parallel to the
cylinder centerline.
Add one half of the main bearing journal diameter to distance
from crankshaft journal to block deck. This dimension should be
checked at front and rear of cylinder block. Both readings should be
the same.
If difference exceeds specifications, cylinder block must be
repaired or replaced. Deck height and warpage should be corrected at
the same time.
MAIN BEARING BORE & ALIGNMENT
For checking main bearing bore, remove all bearings from
cylinder block and main bearing caps. Install main bearing caps in
original location. Tighten bolts to specification. Using inside
micrometer, measure main bearing bore in 2 areas 90 degrees apart.
Determine bore size and out-of-round. If diameter is not within
specification, block must be align-bored.
For checking alignment, place a straightedge along centerline
of main bearing saddles. Check for clearance between straightedge and
main bearing saddles. Block must be align-bored if clearance is
present.
EXPANSION PLUG REMOVAL & INSTALLATION
Removal
Drill a hole in the center of expansion plug. Remove with
screwdriver or punch. Use care not to damage sealing surface.
Installation
Ensure sealing surface is free of burrs. Coat expansion plug
with sealer. Use a wooden dowel or pipe of slightly smaller diameter,
install expansion plug. Ensure expansion plug is evenly located.
OIL GALLERY PLUG REMOVAL & INSTALLATION
Removal
Remove threaded oil gallery plugs using the appropriate
wrench. Soft, press-in plugs are removed by drilling into plug and
installing a sheet metal screw. Remove plug with slide hammer or
pliers.
Installation
Ensure threads or sealing surface is clean. Coat threaded oil
gallery plugs with sealer and install. Replacement soft press-in plugs
are driven in place with a hammer and drift.
CAMSHAFT
* 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.
CLEANING & INSPECTION
Clean camshaft with solvent. Ensure all oil passages are
clear. Inspect cam lobes and bearing journals for pitting, flaking or
scoring. Using micrometer, measure bearing journal O.D.
Support camshaft at each end with "V" blocks. Position dial
indicator with tip resting on center bearing journal. Rotate camshaft
and note reading. If reading exceeds specification, replace camshaft.
Check cam lobe lift by measuring base circle of camshaft
using micrometer. Measure again at 90 degrees to tip of cam lobe. Cam
lift can be determined by subtracting base circle diameter from tip of
cam lobe measurement.
Different lift dimensions are given for intake and exhaust
cam lobes. Reading must be within specifications. Replace camshaft if
cam lobes or bearing journals are not within specifications.
Inspect camshaft gear for chipped, eroded or damaged teeth.
Replace gear if damaged. On camshafts using thrust plate, measure
distance between thrust plate and camshaft shoulder. Replace thrust
plate if not within specification.
CAMSHAFT BEARINGS
Removal & Installation
Remove the camshaft rear plug. The camshaft bearing remover
is assembled with its shoulder resting on the bearing to be removed
according to manufacturer's instructions. Tighten puller nut until
bearing is removed. Remove remaining bearings, leaving front and rear
bearings until last. These bearings act as guide for camshaft bearing
remover.
To install new bearings, puller is rearranged to pull
bearings toward the center of block. Ensure all lubrication passages
of bearing are aligned with cylinder block. Coat new camshaft rear
plug with sealant. Install camshaft rear plug. Ensure plug is even
in cylinder block.
CAMSHAFT INSTALLATION
Lubricate bearing surfaces and cam lobes with ample amount of
Molykote or camshaft lubricant. Carefully install camshaft. Use care
not to damage bearing journals during installation. Install thrust
plate retaining bolts (if equipped). Tighten bolts to specification.
On overhead camshafts, install bearing caps in original location.
Tighten bolts to specification. Check end play.
CAMSHAFT END PLAY
Using dial indicator, check end play. Position dial indicator
on front of engine block. Position indicator tip against camshaft.
Push camshaft toward rear of engine and adjust indicator to zero.
Move camshaft forward and note reading. Camshaft end play
must be within specification. End play may be adjusted by relocating
gear, shimming thrust plate or replacing thrust plate depending on
manufacturer.
TIMING CHAINS & BELTS