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Kubota BX1880, BX1860, BX1800 Engine - Service and Check
Kubota D722 Three-cylinder diesel engine used in BX1880, BX1860, BX1800
tractors.
Kubota BX1880, BX1860, BX1800 Engine - Check
and Maintenance
Checking Engine Oil Level
Level the engine. To check the oil level, draw out the dipstick, wipe it
clean, reinsert it, and draw it out again. Check to see that the oil
level lies between the two notches. If the level is too low, add new oil
to the specified level. Be sure to keep the oil level between upper and
lower limits of the dipstick. Too much oil may cause a drop in output or
excessive blow-by gas. On the closed breather type engine in which mist
is sucked through port, too much oil may caused oil hammer. While too
little oil, may seize the engine’s rotating and sliding parts.
Checking and Replenish Coolant
Without recovery tank: Remove the radiator cap and check to see that the
coolant level is just below the port. With recovery tank: Check to see
that the coolant level lies between FULL and LOW. If coolant level is
too low, check the reason for decreasing coolant. If coolant is
decreasing by evaporation, replenish only fresh, soft water. If coolant
is decreasing by leak, replenish coolant of the same manufacture and
type in the specified mixture ratio (fresh, soft water and L.L.C.). If
the coolant brand cannot be identified, drain out all of the remaining
coolant and refill with a totally new brand of coolant mix.
Changing Engine Oil
Start and warm up the engine for approx. 5 minutes. Place an oil pan
underneath the engine. To drain the used oil, remove the drain plug at
the bottom of the engine and drain the oil completely. Screw the drain
plug. Fill new oil up to upper line on the dipstick. When using an oil
of different maker or viscosity from the previous one, remove all of the
old oil. Never mix two different types of oil. Engine oil should have
properties of API classification CD/CE/CF/CF-4/CG-4. Use the proper SAE
Engine Oil according to ambient temperature. Upon an oil change, be sure
to replace the gasket with new one. Above 25C (77F) - SAE 30 or SAE
10W-30, SAE 10W-40. 0C to 25C (32F to 77F) - SAE 20 or SAE 10W-30, SAE
10W-40. Below 0C (32F) - SAE 10W or SAE 10W-30, SAE 10W-40.
Kubota BX1880, BX1860, BX1800 - Replacing Oil
Filter Cartridge
Remove the oil filter cartridge with the filter wrench. Apply a slight
coat of oil onto the new cartridge gasket. To install the new cartridge,
screw it in by hand. Over tightening may cause deformation of rubber
gasket. After the new cartridge has been replaced, the engine oil
normally decrease a little. Thus see that the engine oil does not leak
through the seal and be sure to read the oil level on the dipstick.
Then, replenish the engine oil up to the specified level.
Checking Fuel Hose
If the clamp is loose, apply oil to the threads and securely retighten
it. The fuel hose is made of rubber and ages regardless of the period
service. Change the fuel hose together with the clamp every two years.
However, if the fuel hose and clamp are found to be damaged or
deteriorate earlier than two years, then change or remedy. After the
fuel hose and the clamp have been changed, bleed the fuel system. When
bleeding fuel system - Fill the tank with fuel and open the cock. Loosen
the air vent plug of the fuel filter a few turns. Screw back the plug
when bubbles do not come up any more. Open the air vent cock on top of
the fuel injection pump. If equipped electrical fuel feed pump, turn the
key to AC position and pump the fuel up for 10 to 15 seconds. If
equipped mechanical fuel feed pump, set the stop lever on stop position
and crank the engine for 10 to 15 seconds. Close securely the air vent
cock after air bleeding. Always keep the air vent cock on the fuel
injection pump closed except when air is vented, or it may cause the
engine to stop.
Fan Belt Tension
Measure the deflection, depressing the belt halfway between the fan
drive pulley and alternator pulley at specified force 98 N (10 kgf, 22
lbs). If the measurement is not within the factory specifications,
loosen the alternator mounting screws and relocate the alternator to
adjust.
Fan Belt Damage and Wear
Check the fan belt for damage. If the fan belt is damaged, replace it.
Check if the fan belt is worn and sunk in the pulley groove. If the fan
belt is nearly worn out and deeply sunk in the pulley groove, replace
it.
Cleaning Air Cleaner Element
Remove the air cleaner element. Use clean dry compressed air on the
inside of the element. Pressure of compressed air must be under 205 kPa
(2.1 kgf/cm2, 30 psi). Maintain reasonable distance between the nozzle
and the filter. The air cleaner uses a dry element. Never apply oil to
it. Do not run Kubota D722 engine with filter element removed. Change
the element once a year or every 6th cleaning.
Kubota BX1880, BX1860, BX1800 - Cleaning Fuel
Filter
Close the fuel cock. Unscrew the retaining ring and remove the filter
cup, and rinse the inside with kerosene. Take out the element and dip it
in the kerosene to rinse. After cleaning, reassemble the fuel filter,
keeping out dust and dirt. Bleed the fuel system. If dust and dirt enter
the fuel, the fuel injection pump and injection nozzle will wear
quickly. To prevent this, be sure to clean the fuel filter cup
periodically.
Checking Radiator Hoses and Clamp Bands
Check to see if the radiator hoses are properly fixed every 200 hours of
operation or every six months, whichever comes first. If the clamp is
loose, apply oil to the threads and retighten it securely. The water
hose is made of rubber and tens to age. It must be replaced every two
years. Also replace the clamp and tighten it securely.
Checking Intake Air Line
Check to see if the intake air hose(s) and the breather hose are
properly fixed every 200 hours of operation. If the clamp is loose,
apply oil to the threads and retighten it securely. The intake air
hose(s) and the breather hose are made of rubber and tends to age. It
must be changed every two years. Also change the clamp and tighten it
securely. To prevent serious damage to the engine, keep out any dust
inside the intake air line.
Replacing Fuel Filter Cartridge (Cartridge
Type)
Water and dust in fuel are collected in the filter cartridge. So, change
the filter cartridge every 400 hours service. Remove the used filter
cartridge with filter wrench. Apply a thin film of fuel to the surface
of new filter cartridge gasket before screwing on. Then tighten enough
by hand. Loosen the air vent plug to let the air out. Start engine and
check for fuel leakage.
Replacing Fuel Filter Element (Element Type)
Close the fuel cock. Unscrew the retaining ring and remove the filter
cup, and rinse the inside with kerosene. Replace the filter element.
Reassemble the fuel filter, keeping out dust and dirt. Bleed the fuel
system.
Cleaning Water Jacket and Radiator Interior
Stop a Kubota D722 engine and let cool down. To drain the coolant, open
the radiator drain plug and remove the radiator cap. Then radiator cap
must be removed to completely drain the coolant. And open the drain
cock. After all coolant is drained, close the drain plug. Fill with
clean water and cooling system cleaner. Follow directions of the cleaner
instruction. After flushing, fill with clean water and anti-freeze until
the coolant level is just below the port. Install the radiator cap
securely. Fill with coolant up to FULL mark on the recovery tank. Start
and operate the engine for few minutes. Stop the engine and let cool.
Check coolant level of radiator and recovery tank and add coolant if
necessary.
Replacing Fan Belt
Remove the alternator. Remove the fan belt. Replace new fan belt.
Install the alternator. Check the fan belt tension. Deflection - 7.0 to
9.0 mm / 98 N 0.28 to 0.35 in. / 98 N (10 kgf, 22 lbs).
Checking Injection Pump
Remove the engine stop solenoid. Remove the injection pipes and glow
plugs. Install the injection pump pressure tester to the injection pump.
Install the injection nozzle jetted with the proper injection pressure
to the injection pump pressure tester. Set the speed control lever to
the maximum speed position. Run the starter to increase the pressure. If
the pressure can not reach the allowable limit, replace the pump with
new one or repair.
Replacing Intake Air Line
Loosen the clamp. Remove the intake air hose and clamp. Replace new
intake air hose and new clamp. Tighten the clamp. To prevent serious
damage to the engine, keep out any dust inside the intake air line.
Replacing Battery
Disconnect the negative terminal and positive terminal. Remove the
battery holder. Remove the used battery. Replace the new battery.
Tighten the battery holder. Connect the positive terminal. Connect the
negative terminal.
Replacing Radiator Hoses and Clamp Bands
Drain the coolant. Loosen the clamp bands. Remove the upper hose and
lower hose. Replace new upper / lower hose and clamp bands. Tighten the
clamp bands. Fill with clean water and anti-freeze until the coolant
level is just below the port. Install the radiator cap securely.
Kubota BX1880, BX1860, BX1800 - Engine
Disassembly
Starter
Unscrew the C terminal nut, and disconnect the connecting lead. Unscrew
the solenoid switch mounting nuts, and remove the solenoid switch.
Remove the end frame cap. Remove the brake shoe, brake spring and
gasket. Unscrew the through bolts, and remove the rear end frame. Remove
the brush from the brush holder while holding the spring up. Remove the
brush holder. Draw out the yoke from the starter drive housing. Draw out
the armature with the drive lever.
Alternator
Remove the pulley. Remove the rear end cover. Remove the brush holder.
Remove the IC regulator. Remove the four screws holding the stator lead
wires. Remove the rectifier. Remove the rear end frame. Press out the
rotor from drive end frame. Remove the retainer plate. Press out the
bearing from drive end frame with a press and jig. Lightly secure the
rotor with a vise to prevent damage, and remove the bearing with a
puller.
Cylinder Head
Loosen the pipe clamps, and remove the water return pipe. Remove the
cylinder head screw in the order. Lift up the cylinder head to detach.
Remove the cylinder head gasket and O-ring. Replace the cylinder head
gasket with a new one. Securely fit the O-ring to the pipe pin. Tighten
the cylinder head screws after applying sufficient oil. Tighten the
cylinder head screws in order. Tighten them uniformly, or the head may
deform in the long run. Retighten the cylinder head screws after running
the engine for 30 minutes. Cylinder Head Cover - Disconnect the breather
hose. Remove the cylinder head cover screws. Remove the cylinder head
cover. Check to see if the cylinder head cover gasket is not defective.
Injection Pipes
Loosen the screws to the pipe clamp. Detach the injection pipes. Sent
compressed air into the pipes to blow out dust. Then, reassemble the
pipes in the reverse order.
Nozzle Heat Seal Service Removal Procedure
Use a plus (phillips head) screw driver that has a diameter which is
bigger than the heat seal hole (Approx. 6 mm (1/4 in.). Drive screw
driver lightly into the heat seal hole. Turn screw driver three or four
times each way. While turning the screw driver, slowly pull the heat
seal out together with the injection nozzle gasket. If the heat seal
drops, repeat the above procedure. Heat seal and injection nozzle gasket
must be changed when the injection nozzle is removed for cleaning or for
service.
Rocker Arm and Push Rod
Remove the rocker arm bracket screws. Detach the rocker arm assembly.
Remove the push rods. When putting the push rods onto the tappets, check
to see if their ends are properly engaged with the dimples.
Thermostat Assembly
Remove the thermostat cover mounting screws, and remove the thermostat
cover. Remove the thermostat assembly. Apply a liquid gasket only at the
thermostat cover side of the gasket.
Tappets
Remove the tappets from the crankcase. Visually check the contact
between tappets and cams for proper rotation. If defect is found,
replace tappets. Before installing the tappets, apply engine oil thinly
around them. Do not change the combination of tappet and tappet guide.
Valves
Remove the valve caps. Remove the valve spring collet, pushing the valve
spring retainer by valve spring replacer. Remove the valve spring
retainer, valve spring and valve stem seal. Remove the valve. Wash the
valve stem and valve guide hole, and apply engine oil sufficiently.
After installing the valve spring collets, lightly tap the stem to
assure proper fit with a plastic hammer.
Oil Pan and Oil Strainer
Remove the oil pan mounting screws. Remove the oil pan by lightly
tapping the rim of the pan with a wooden hammer. Remove the oil
strainer. After cleaning the oil strainer, check to see that the filter
mesh in clean, and install it. Visually check the O-ring, apply engine
oil, and install it. Securely fit the O-ring to the oil strainer. To
avoid uneven tightening, tighten oil pan mounting screws in diagonal
order form the center. Using the hole numbered “3”, install the oil
strainer by mounting screw
Kubota BX1880, BX1860, BX1800 - Gear Case and
Timing Gears
Injection Pump, Fuel Feed Pump and Speed
Control Plate (for Energize to Stop Type Engine Stop Solenoid)
Remove the socket head screws and nuts, and remove the injection pump.
Remove the screws and separate the speed control plate, taking care not
to damage the governor spring. Disconnect the governor spring and remove
the speed control plate. Remove the fuel feed pump. Hook the governor
spring to the governor lever first and install the speed control plate.
Be sure to place the copper washers underneath two screws (Two screws in
the upper of the speed control plate). Position the slot on the fork
lever just under the slot on the crankcase. Insert the injection pump so
that the control rod should be pushed by the idling adjusting spring at
its end and the pin on the rod engages with the slot on the fork lever.
The sealant is applied to both sides of the soft metal gasket shim. The
liquid gasket is not required for assembling. Addition or reduction of
shim (0.05 mm, 0.0020 in.) delays or advances the injection timing by
approx. 0.0087 rad (0.5°). In disassembling and replacing, be sure to
use the same number of new gasket shims with the same thickness.
Injection Pump, Fuel Feed Pump and Speed
Control Plate (for Energize to Run Type Engine Stop Solenoid)
Move the fork lever to the gear case side. Hook the start spring to the
injection pump control rack pin. Put the specific tool through the fork
lever hole of cylinder block and hook the start spring. Keep this spring
slightly extended and install the injection pump. Make sure the control
rod should be pushed by the idling adjusting spring and the pin on the
rod engages with the fork lever. Hook the start spring to the bracket
using the specific tool. Hook the governor springs (small and large) to
the governor lever using the specific tool and install the speed control
plate. Be sure to place the copper washers underneath two screws in the
upper of the speed control plate. Install the engine stop solenoid rod
to the guide hole of cylinder block and fix the engine stop solenoid
with socket head screws.
Fan Drive Pulley
Secure the flywheel to keep it from turning. Remove the fan drive pulley
screw. Draw out the fan drive pulley with a puller. Install the pulley
to crankshaft, aligning the mark on them. Apply engine oil to the fan
drive pulley retaining screw. And tighten it.
Gear Case
Disconnect the start spring from the fork lever 1. Remove the screw of
inside the gear case and outside screws. Remove the gear case. Apply a
liquid gasket to both sides of the gear case gasket. Be sure to set
three O-rings inside the gear case.
Idle Gear
Remove the external snap ring, the collar and the idle gear. Remove the
idle gear shaft mounting screws. Remove the idle gear shaft (if
necessary). Apply engine oil to the idle gear shaft mounting screw. And
tighten them. Install the idle gear, aligning the mark on the gears.
Camshaft
Remove the camshaft mounting screws and draw out the camshaft with gear
on it. When install the camshaft, apply engine oil to the camshaft
journals. Apply engine oil to the camshaft mounting screws. And tighten
them.
Fuel Camshaft
Remove the retaining plate. Remove the fork lever holder mounting
screws, then draw out the injection pump gear and fuel camshaft with the
governor fork assembly. Hook the governor spring to the fork lever 2
before installing the fork lever assembly to the crankcase.
Oil Pump and Crankshaft Gear
Remove the oil pump gear. Remove the oil pump mounting screw and the oil
pump. Remove the collar, O-ring and crankshaft oil slinger. Install the
collar after aligning the marks on the gears.
Kubota BX1880, BX1860, BX1800 - Piston and
Connecting Rod
Connecting Rod Cap
Remove the connecting rod caps using a bihexagonal 8 mm socket. Align
the marks with each other (Face the marks toward the injection pump).
Apply engine oil to the connecting rod screws and lightly screw it in by
hand, then tighten it to the specified torque. If the connecting rod
screw won’t be screwed in smoothly, clean the threads. If the connecting
rod screw is still hard to screw in, replace it.
Piston
Turn the flywheel and bring the piston to top dead center. Draw out the
piston upward by lightly tapping it from the bottom of the crankcase
with the grip of a hammer. Draw out the other pistons after the same
method as above. Before inserting the piston into the cylinder, apply
enough engine oil to the cylinder. When inserting the piston into the
cylinder, face the mark on the connecting rod to the injection pump.
Piston Ring and Connecting Rod
Remove the piston rings using a piston ring tool. Remove the piston pin,
and separate the connecting rod from the piston. When installing the
ring, assemble the rings so that the manufacturer’s mark near the gap
faces the top of the piston. When installing the oil ring onto the
piston, place the expander joint on the opposite side of the oil ring
gap. Apply engine oil to the piston pin. When installing the connecting
rod to the piston, immerse the piston in 80C (176F) oil for 10 to 15
minutes and insert the piston pin to the piston. When installing the
connecting rod to the piston, align the mark on the connecting rod to
the fan-shaped concave.
Kubota BX1880, BX1860, BX1800 - Flywheel and
Crankshaft
Flywheel
Secure the flywheel to keep it from turning using a flywheel stopper.
Remove all flywheel screws and then remove the flywheel. Set the No. 1
crankpin at the top dead center (T.D.C.). Align the 1TC mark on the
outer surface of the flywheel horizontally with the alignment mark on
the rear end plate. Apply engine oil to the threads and the undercut
surface of the flywheel screw and fit the screw.
Bearing Case Cover
Remove the bearing case cover mounting screws. First, remove inside
screws and then outside screws. Remove the bearing case cover. Fit the
bearing case gasket and the bearing case cover gasket with correct
directions. Install the bearing case cover to position the casting mark
UP on it upward. Apply engine oil to the oil seal lip and take care that
it is not rolled when installing. Tighten the bearing case cover
mounting screws with even force on the diagonal line.
Crankshaft Assembly
Remove the main bearing case screw 2. Turn the crankshaft to set the
crankpin of the third cylinder to the bottom dead center. Then draw out
the crankshaft until the crankpin of the second cylinder comes to the
center of the third cylinder. Turn the crankshaft by 2.09 rad (120°)
counterclockwise to set the crankpin of the second cylinder to the
bottom dead center. Draw out the crankshaft until the crankpin of the
first cylinder comes to the center of the third cylinder. Repeat the
above steps to draw out all the crankshaft. Clean the oil passage of the
crankshaft with compressed air. Install the crankshaft assembly,
aligning the screw hole of main bearing case screw 2 with the screw hole
of crankcase. When tightening the main bearing case 2, apply oil to the
main bearing case screw 2 and screw by hand before tightening the
specific torque. If not smooth to screw by hand, align the screw holes
between the crankcase and the main bearing case.
Main Bearing Case Assembly
Remove the two main bearing case screws 1, and remove the main bearing
case assembly 1, being careful with crankshaft bearing 3. Remove the
main bearing case assembly 2 and the main bearing case assembly as
above. Keep in mind, however, that the thrust bearing is installed in
the main bearing case assembly. Clean the oil passage in the main
bearing cases. Apply clean engine oil to the bearings. Install the main
bearing case assemblies in original positions. Since diameters of main
bearing cases vary, install them in order of marking from the gear case
side. Match the alignment numbers on the main bearing case assembly 1.
Do the same for the main bearing case assembly 2 and the main bearing
case assembly too. When installing the main bearing case 1 and 2, face
the mark FLYWHEEL to the flywheel. Install the thrust bearing with its
oil groove facing outward.
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