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Kubota B2530, B2400, B2410 Engine - Checking and Service

Kubota B2530, B2400, B2410 tractors are equipped with a D1105 3-cylinder diesel engine.

Kubota B2530, B2400, B2410 Engine Checking

Checking Fan Belt Tension

Be sure to stop engine before checking belt tension. Stop the engine and remove the key. Apply moderate thumb pressure to belt between pulleys. If tension is incorrect, loosen the alternator mounting bolts and, using a lever placed between the alternator and the engine block, pull the alternator out until the deflection of the belt falls within acceptable limits. Replace fan belt if it is damaged. Fan belt tension - Deflection of between 7 to 9 mm (0.28 to 0.34 in.) when the belt is pressed in the middle of the span.

Checking Fuel Line

Check to see that all line and hose clamps are tight and not damaged. If hoses and clamps are found worn or damaged, replace or repair them at once. The fuel line is made of rubber and ages regardless of period of service. Replace the fuel pipe together with the clamp every two years and securely tighten. However if the fuel pipe and clamp are found damaged or deteriorated earlier than two years, then change or remedy. After the fuel line and clamp have been changed, bleed the fuel system.

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 in the drain plug. Fill new oil up to upper line on the dipstick. When using an oil of different manufacture or viscosity from the previous one, remove all of the old oil. Never mix two different types of oil.

Replacing Engine Oil Filter Cartridge

Remove the oil filter cartridge with the filter wrench. Apply a slight coat of oil onto the 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.

Cleaning Air Cleaner Element

Remove the air cleaner cover and primary element. Clean the primary element if: When dry dust adheres to the element, blow compressed air from the inside turning the element. Pressure of compressed air must be under 686 kPa (7 kgf/cm2, 99 psi). When carbon or oil adheres to the element, soak the element in detergent for 15 minutes then wash it several times in water, rinse with clean water and dry it naturally. After element is fully dried, inspect inside of the element with a light and check if it is damaged or not. When replacing the air cleaner primary element, replace the secondary element as well: Once a year or after every six times of cleaning, whichever comes first.

Cleaning Fuel Filter

This job should not be done in the field, but in a clean place. Loosen and remove the fuel filter bowl, and rinse the inside with kerosene. Take out the filter element and dip it in the kerosene to rinse. After cleaning, reassemble the fuel filter, keeping out dust and dirt. Bleed the fuel system. When the fuel filter bowl has been removed, fuel stops flowing from the fuel tank. If the fuel tank is almost full, however, the fuel will flow back from the fuel return pipe to the fuel filter. Before the above checking, make sure the fuel tank is less than half-full.

Checking Radiator Hose and Hose Clamp

Check to see if radiator hoses are properly fixed every 200 hours of operation or six months, whichever comes first. If hose clamps are loose or water leaks, tighten bands securely. Replace hoses and tighten hose clamps securely, if radiator hoses are swollen, hardened or cracked. Replace hoses and hose clamps every 2 years or earlier if checked and found that hoses are swollen, hardened or cracked.

Checking Intake Air Line

Check to see that hoses and hose clamps are tight and not damaged. If hoses and clamps are found worn or damaged, replace or repair them at once.

Flush Cooling System and Changing Coolant

Stop the engine and let cool down. To drain the coolant, open the radiator drain cock, and remove radiator cap. The radiator cap must be removed to completely drain the coolant. 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. Start and operate the engine for few minutes. Stop the engine. Check coolant level and add coolant if necessary. Install the radiator cap securely.

Bleeding Fuel System

Air must removed: When the fuel filter or lines are removed. When tank is completely empty. After the tractor has not been used for a long period of time. Bleeding procedure is as follows: Fill the fuel tank with fuel. Start the engine and run for about 30 seconds, and then stop the engine.

Kubota B2530, B2400, B2410 - Engine Servicing

Cylinder Head Surface Flatness

Clean the cylinder head surface. Place a straightedge on the cylinder head's four sides and two diagonal. Measure the clearance with a feeler gauge. If the measurement exceeds the allowable limit, correct it with a surface grinder. Do not place the straightedge on the combustion chamber. Be sure to check the valve recessing after correcting. Cylinder head surface flatness - Allowable limit 0.05 mm (0.0019 in).

Cylinder Head Flaw

Prepare an air spray red check. Clean the surface of the cylinder head with detergent. Spray the cylinder head surface with the red permeative liquid. Leave it five to ten minutes after spraying. Wash away the red permeative liquid on the cylinder head surface with the detergent. Spray the cylinder head surface with white developer. If flawed, it can be identified as red marks.

Valve Recessing

Clean the cylinder head surface, valve face and valve seat. Insert the valve into the valve guide. Measure the valve recessing with a depth gauge. If the measurement exceeds the allowable limit, replace the valve. If it still exceeds the allowable limit after replacing the valve, correct the valve seat face of the cylinder head with a valve seat cutter or valve seat grinder. Then, correct the cylinder head surface with a surface grinder, or replace the cylinder head. Valve recessing - 0.05 (protrusion) to 0.15 (recessing) mm.

Clearance between Valve Stem and Valve Guide

Remove carbon from the valve guide section. Measure the valve stem O.D. with an outside micrometer. Measure the valve guide I.D. with a small hole gauge, and calculate the clearance. If the clearance exceeds the allowable limit, replace the valves. If it still exceeds the allowable limit, replace the valve guide. Clearance between valve stem and valve guide - 0.035 to 0.065 mm (0.00138 to 0.00256 in). Valve stem O.D. - 6.960 to 6.975 mm (0.27402 to 0.27461 in). Valve guide I.D. - 7.010 to 7.025 mm (0.27599 to 0.27657 in).

Replacing Valve Guide

Press out the used valve guide using a valve guide replacing tool. Clean a new valve guide and valve guide bore, and apply engine oil to them. Press in a new valve guide using a valve guide replacing tool. Ream precisely the I.D. of the valve guide to the specified dimension. Valve guide I.D. (Intake and exhaust) - 7.010 to 7.025 mm (0.27599 to 0.27657 in).

Valve Seating

Coat the valve face lightly with prussian blue and put the valve on its seat to check the contact. If the valve does not seat all the way around the valve seat or the valve contact is less than 70%, correct the valve seating as follows. If the valve contact does not comply with the reference value, replace the valve or correct the contact of valve seating.

Correcting Valve and Valve Seat

After correcting the valve seat, be sure to check the valve recessing. Correct the valve with a valve refacer. Slightly correct the seat surface with a 1.047 rad. (60°) (intake valve) or 0.785 rad. (45°) (exhaust valve) seat cutter. Resurface the seat surface with a 0.523 rad. (30°) valve seat cutter to intake valve seat and with a 0.262 rad. (15°) valve seat cutter to exhaust valve seat so that the width is close to specified valve seat width (2.12 mm, 0.0835 in.). After resurfacing the seat, inspect for even valve seating, apply a thin film of compound between the valve face and valve seat, and fit them with valve lapping tool. Check the valve seating with prussian blue. The valve seating surface should show good contact all the way around.

Valve Lapping

Apply compound evenly to the valve lapping surface. Insert the valve into the valve guide. Lap the valve onto its seat with a valve flapper or screwdriver. After lapping the valve, wash the compound away and apply oil, then repeat valve lapping with oil. Apply prussian blue to the contact surface to check the seated rate. If it is less than 70 0/0, repeat valve lapping again. When valve lapping is performed, be sure to check the valve recessing and adjust the valve clearance after assembling the valve.

Free Length and Tilt of Valve Spring

Measure the free length (A) of valve spring with vernier calipers. If the measurement is less than the allowable limit, replace it. Put the valve spring on a surface plate, place a square on the side of the valve spring. Check to see if the entire side is in contact with the square. Rotate the valve spring and measure the maximum tilt. If the measurement exceeds the allowable limit, replace it. Check the entire surface of the valve spring for scratches. If there is any defect, replace it. Free length - Allowable limit 36.5 mm . Tilt 1.0 mm (0.039 in).

Valve Spring Setting Load

Place the valve spring on a tester and compress it to the same length it is actually compressed in the engine. Read the compression load on the gauge. If the measurement is less than the allowable limit, replace it.

Oil Clearance between Rocker Arm and Rocker Arm Shaft

Measure the rocker arm shaft 0.0. with an outside micrometer. Measure the rocker arm 1.0. with an inside micrometer, and then calculate the oil clearance. If the oil clearance exceeds the allowable limit, replace the rocker arm and measure the oil clearance again. If it still exceeds the allowable limit, replace also the rocker arm shaft. Oil clearance between rocker arm and rocker arm shaft - 0.016 to 0.045 mm (0.00063 to 0.00177 in). Rocker arm shaft O.D. - 11.973 to 11.984 mm (0.47138 to 0.47181 in). Rocker arm I.D. - 12.000 to 12.018 mm (0.47244 to 0.47315 in).

Push Rod Alignment

Place the push rod on V blocks. Measure the push rod alignment. If the measurement exceeds the allowable limit, replace the push rod. Push rod alignment Allowable limit - 0.25 mm (0.0098 in).

Oil Clearance between Tappet and Tappet Guide Bore

Measure the tappet O.D. with an outside micrometer. Measure the I.D. of the tappet guide bore with a cylinder gauge, and calculate the oil clearance. If the oil clearance exceeds the allowable limit or the tappet is damaged, replace the tappet. Oil Clearance between tappet and tappet guide bore 0.020 to 0.062 mm (0.00079 to 0.00244 in). Allowable limit 0.07 mm (0.0028 in). Tappet O.D. - 19.959 to 19.980 mm (0.78579 to 0.78661 in). Tappet guide bore I.D. - 20.000 to 20.021 mm (0.78740 to 0.78823 in).

Kubota B2530, B2400, B2410 - Timing Gears, Camshaft and Fuel Camshaft

Timing Gear Backlash

Set a dial indicator (lever type) with its tip on the gear tooth. Move the gear to measure the backlash, holding its mating gear. If the backlash exceeds the allowable limit, check the oil clearance of the shafts and the gear. If the oil clearance is proper, replace the gear. Backlash between idle gear and crank gear 0.032 to 0.115 mm / 0.00120 to 0.00453 in. Backlash between idle gear and cam gear 0.036 to 0.114 mm / 0.00142 to 0.00449 in. Backlash between idle gear and injection pump gear 0.034 to 0.116 mm / 0.00134 to 0.00457 in. Backlash between injection pump gear and governor gear 0.030 to 0.117 mm / 0.00118 to 0.00461 in.

Idle Gear Side Clearance

Set a dial indicator with its tip on the idle gear. Measure the side clearance by moving the idle gear to the front and rear. If the measurement exceeds the allowable limit, replace the idle gear collar. Idle gear side clearance - 0.050 to 0.150 mm (0.0020 to 0.0059 in).

Camshaft Side Clearance

Set a dial indicator with its tip on the camshaft. Measure the side clearance by moving the cam gear to the front and rear. If the measurement exceeds the allowable limit, replace the camshaft stopper. Camshaft side clearance - 0.07 to 0.22 mm (0.0028 to 0.0087 in).

Camshaft Alignment

Support the camshaft with V blocks on the surface plate at both end journals. Set a dial indicator with its tip on the intermediate journal. Measure the camshaft alignment. If the measurement exceeds the allowable limit, replace the camshaft. Camshaft alignment - Allowable limit 0.01 mm / 0.0004 in.

Cam Height

Measure the height of the cam at its highest point with an outside micrometer. If the measurement is less than the allowable limit, replace the camshaft. Cam height of intake - 28.80 mm / 1.1339 in. Cam height of exhaust - 29.00 mm / 1.1417 in.

Oil Clearance of Camshaft Journal

Measure the camshaft journal O.D. with an outside micrometer. Measure the cylinder block bore I.D. for camshaft with a cylinder gauge, and calculate the oil clearance. If the oil clearance exceeds the allowable limit, replace the camshaft. Oil clearance of camshaft journal 0.00197 to 0.00358 in. Camshaft journal O.D. Factory spec. 35.934 to 35.950 mm / 1.41473 to 1.41535 in. Cylinder block bore I.D. - 36.000 to 36.025 mm / 1.41732 to 1.41830 in.

Oil Clearance between Idle Gear Shaft and Idle Gear Bushing

Measure the idle gear shaft O.D. with an outside micrometer. Measure the idle gear bushing I.D. with an inside micrometer, and calculate the oil clearance. If the oil clearance exceeds the allowable limit, replace the bushing. If it still exceeds the allowable limit, replace the idle gear shaft. Oil clearance between idle gear shaft and Idle Gear Bushing 0.020 to 0.054 mm / 0.00079 to 0.00213 in. Idle gear shaft O.D. 25.967 to 25.980 mm / 1.02232 to 1.02283 in. Idle gear bushing I.D. 26.000 to 26.021 mm / 1.02362 to 1.02445 in.

Replacing Idle Gear Bushing

Press out the used idle gear bushing using an idle gear bushing replacing tool. Clean a new idle gear bushing and idle gear bore, and apply engine oil to them. Press in a new bushing using an idle gear bushing replacing tool, until it is flush with the end of the idle gear.

Kubota B2530, B2400, B2410 - Piston and Connecting Rod

Piston Pin Bore O.D.

Measure the piston pin bore O.D. in both the horizontal and vertical directions with a cylinder gauge. If the measurement exceeds the allowable limit, replace the piston. Piston pin bore O.D. 22.000 to 22.013 mm / 0.86614 to 0.86665 in.

Oil Clearance between Piston Pin and Small End Bushing

Measure the piston pin O.D. where it contacts the bushing with an outside micrometer. Measure the small end bushing I.D. with an inside micrometer, and calculate the oil clearance. If the oil clearance exceeds the allowable limit, replace the bushing. If it still exceeds the allowable limit, replace the piston pin. Oil clearance between piston pin and small end bushing 0.014 to 0.038 mm / 0.00055 to 0.00150 in. Piston pin O.D. 22.002 to 22.011 mm / 0.86622 to 0.86657 in. Small end bushing I.D. 22.025 to 22.040 mm / 0.86713 to 0.86771 in.

Replacing Small End Bushing

Press out the used bushing using a small end bushing replacing tool. Clean a new small end bushing and bore, and apply engine oil to them. Insert a new bushing onto the tool and press-fit it with a press so that the seam (1) of bushing positions as shown in the figure, until it is flash with the connecting rod. Drill a hole to the bushing with aligning the oil hole (2) of connecting rod using 4.0 mm dia. (0.157 in. dia.) drill.

Piston Ring Gap

Insert the piston ring into the lower part of the cylinder (the least worn out part) with a piston ring compressor and piston. Measure the ring gap with a feeler gauge. If the measurement exceeds the allowable limit, replace the piston ring. Top ring and Second ring - 0.25 to 0040 mm / 0.0098 to 0.0157 in. Oil ring - 0.25 to 0045 mm / 0.0098 to 0.0177 in.

Clearance between Piston Ring and Piston Ring Groove

Clean the rings and the ring grooves, and install each ring in its groove. Measure the clearance between the ring and the groove with a feeler gauge. If the clearance exceeds the allowable limit, replace the piston ring. If the clearance still exceeds the allowable limit with new ring, replace the piston. Second ring - 0.085 to 0.112 mm / 0.00335 to 0.00441 in. Oil ring - 0.020 to 0.055 mm / 0.00079 to 0.00217 in.

Connecting Rod Alignment

Remove the crankpin bearing, and install the connecting rod cap. Install the piston pin in the connecting rod. Install the connecting rod on the connecting rod alignment tool. Put a gauge over the piston pin, and move it against the face plate. If the gauge does not fit squarely against the face plate, measure the space between the pin of the gauge and the face plate. If the measurement exceeds the allowable limit, replace the connecting rod.

Kubota B2530, B2400, B2410 - Crankshaft

Crankshaft Side Clearance

Set a dial indicator with its tip on the end of the crankshaft. Measure the side clearance by moving the crankshaft to the front and rear. If the measurement exceeds the allowable limit, replace the thrust bearings. If the same size bearing is useless because of the crankshaft journal wear, replace it with an oversize. Crankshaft side clearance 0.15 to 0.31 mm / 0.0059 to 0.0122 in.

Crankshaft Alignment

Support the crankshaft with V blocks on the surface plate at both end journals. Set a dial indicator with its tip on the intermediate journal. Measure the crankshaft alignment. If the measurement exceeds the allowable limit, replace the crankshaft.

Oil Clearance between Crankpin and Crankpin Bearing

Clean the crankpin and crankpin bearing. Put a strip of plastigage on the center of the crankpin. Install the connecting rod cap and tighten the connecting rod screws to the specified torque, and remove the cap again. Measure the amount of the flattening with the scale, and get the oil clearance. If the oil clearance exceeds the allowable limit, replace the crankpin bearing. If the same size bearing is useless because of the crankpin wear, replace it with an undersize one. Never insert the plastigage into the crankpin oil hole. Be sure not to move the crankshaft while the connecting rod screws are tightened. Oil clearance between crankpin and crankpin bearing 0.029 to 0.091 mm / 0.00114 to 0.00358 in. Crankpin O.D. 39.959 to 39.975 mm / 1.57319 to 1.57382 in. Crankpin bearing I.D. 40.004 to 40.050 mm / 1.57496 to 1.57677 in.

Oil Clearance between Crankshaft Journal and Crankshaft Bearing 1

Measure the O.D. of the crankshaft front journal with an outside micrometer. Measure the I.D. of the crankshaft bearing 1 with an inside micrometer, and calculate the oil clearance. If the oil clearance exceeds the allowable limit, replace the crankshaft bearing 1. If the same size bearing is useless because of the crankshaft journal wear, replace it with an undersize one. Oil clearance between crankshaft journal and crankshaft bearing 1 - 0.034 to 0.114 mm / 0.00134 to 0.00449 in. Crankshaft journal O.D. - 47.934 to 47.950 mm / 1.88716 to 1.88779 in. Crankshaft bearing 1 I.D. - 47.984 to 48.048 mm / 1.88913 to 1.89165 in.

Oil Clearance between Crankshaft Journal and Crankshaft Bearing 2 (Crankshaft Bearing 3)

Put a strip of plastigage on the center of the journal. Install the bearing case and tighten the bearing case screws 1 to the specified torque, and remove the bearing case again. Measure the amount of the flattening with the scale, and get the oil clearance. If the oil clearance exceeds the allowable limit, replace the crankshaft bearing 2 (crankshaft bearing 3). If the same size bearing is useless because of the crankshaft journal wear, replace it with an undersize one. Be sure not to move the crankshaft while the bearing case screws are tightened. Oil clearance between crankshaft journal and crankshaft bearing 2 - 0.034 to 0.095 mm / 0.00134 to 0.00374 in. Crankshaft journal O.D. - 47.934 to 47.950 mm / 1.88716 to 1.88779 in. Crankshaft bearing 2 I.D. - 47.984 to 48.029 mm / 1.88913 to 1.89091 in. Oil clearance between crankshaft journal and crankshaft bearing 3 - 0.034 to 0.098 mm / 0.00134 to 0.00386 in. Crankshaft journal O.D. - 51.921 to 51.940 mm / 2.04413 to 2.04488 in. Crankshaft bearing 3 I.D. - 51.974 to 52.019 mm / 2.04622 to 2.04799 in.