Caterpillar Cat 621E WHEEL TRACTOR (Prefix 6AB) Service Repair Manual Instant Download.pdf

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Product: WHEEL TRACTOR
Model: 621E WHEEL TRACTOR 6AB
Configuration: 621E TRACTOR-SCRAPER / POWER SHIFT / 6AB00001-01427 (MACHINE) POWERED BY 3406 ENGINE
Disassembly and Assembly
3406C DIESEL ENGINES FOR CATERPILLAR BUILT MACHINES
Media Number -SENR6409-02 Publication Date -01/07/2006 Date Updated -19/05/2015
SENR64090027
Spacer Plate
SMCS - 1221-011; 1221-012
Remove Spacer Plate
Start By:
a. remove cylinder head assembly
1. Remove spacer plate (1) from the cylinder block.
NOTICE
Do not cause damage to the dowels.
2. Remove the spacer plate gasket and two O-ring seals.
Install Spacer Plate
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1. Thoroughly clean the spacer plate and cylinder block surface. Install two O-ring seals (1) in the
cylinder block.
NOTICE
Both surfaces of the spacer plate, top of cylinder block and both sides
of the spacer plate gasket must be clean and dry. Gasket adhesives or
other substances must not be used on these surfaces.
2. Install a new gasket between the spacer plate and cylinder block. Put spacer plate (2) in position
on the cylinder block.
3. Check cylinder liner projection. See topic, "Install Cylinder Liners".
End By:
a. install cylinder head assembly
Copyright 1993 - 2021 Caterpillar Inc.
All Rights Reserved.
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Mon Mar 29 18:10:49 UTC+0800 2021
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SENR64090028
Valves
SMCS - 1105-011; 1105-012
Remove Valves
Start By:
1. Use Tool (A) to compress springs (1).
2. Remove the locks.
3. Remove Tool (A), the valve, the rotocoil, and the spring.
NOTE: If a valve can be used again, put identification on the valve for location at installation.
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4. Use Tool (B) to check spring force. The specifications for the spring are given in Specifications
Manual, SENR6470.
5. Do Steps 1 through 4 again for the remainder of the valves.
Install Valves
1. Put clean engine oil on the valve stem. Install washer (3), spring (2), rotocoil (1) and the valve.
2. Use Tool (A) to compress the spring.
3. Install locks (4) with the thick end up.
Locks can be thrown from valve when compressor is released, if they
are not in their correct position on the valve stem.
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4. Remove the compressor and hit the valve with a soft faced hammer to be sure locks are in their
correct position on the valve.
5. Do Steps 1 through 4 again for the remainder of the valves.
End By:
a. install cylinder assembly
Mon Mar 29 18:11:45 UTC+0800 2021
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SENR64090029
Valve Seat Inserts
SMCS - 1103-010
Remove & Install Valve Seat Inserts
Start By:
a. remove valves
1. Use Tool (A) to remove the valve seat inserts from the cylinder head.
2. Clean and remove any burrs from the valve seat bores.
NOTE: For reconditioning information of the cylinder head, see Service Training Meeting Guide,
SESV1202.
NOTE: The following steps are for the installation of the valve seat inserts.
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3. Lower the temperature of the new valve seat inserts. Use Tool (B) to install the new valve seat
inserts in the cylinder head.
End By:
a. install valves
Mon Mar 29 18:12:40 UTC+0800 2021
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SENR64090030
Bridge Dowels
SMCS - 1121-011; 1121-012
Remove Bridge Dowels
Start By:
a. remove valves
1. Use Tool (A) to remove bridge dowel (1).
Install Bridge Dowels
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1. Use Tool (A) to install the bridge dowel.
End By:
a. install valves
Mon Mar 29 18:13:36 UTC+0800 2021
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SENR64090031
Valve Guides
SMCS - 1104-011; 1104-012
Remove Valve Guides
Start By:
a. remove valves
1. Use Tool (A) to remove the valve guides.
Install Valve Guides
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1. Put clean engine oil on the outside of the valve guide.
2. Use Tool (A) to install the valve guides.
3. After installation, the inside diameter of the valve guide must be 9.487 ± 0.025 mm (.3735
± .0010 in). The maximum diameter of used guides is 8.538 mm (.3361 in).
End By:
a. install valves
Mon Mar 29 18:14:32 UTC+0800 2021
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SENR64090032
Oil Pan & Plate
SMCS - 1302-011; 1302-012
Remove Oil Pan & Plate
Typical Example
1. Drain the oil from the engine into a suitable container for storage or disposal.
2. Remove the lower clamp and bracket that hold the breather tube to the cylinder block and oil
pan.
3. Remove all but four of the bolts (1) that hold the oil pan to the cylinder block.
Use two persons to hold the oil pan in position while the last four bolts
are removed.
4. Remove the oil pan (2). Weight of the oil pan is 57 kg (126 lb).
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5. Remove suction bell (3). Remove suction bell and tube (4). Remove oil supply tube (5).
Remove plate (6).
Install Oil Pan & Plate
1. Put plate (1) in position on the cylinder block. Put suction bell and tube (2) in position on the oil
pump and cylinder block. Install the bolts that hold it.
2. Install oil supply tube (4).
3. Install the suction bell (3).
4. Install two 3/8 in 16 NC Guide Pins 6 in long in the cylinder block. Put the oil pan (5) in
position on the cylinder block. Install all but two of the bolts that hold it. Remove the two guide
pins. Install the last two bolts.
5. Fill the engine with oil to the correct level. See the Operation & Maintenance Manual.
Mon Mar 29 18:15:28 UTC+0800 2021
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SENR64090033
Oil Pump
SMCS - 1304-016; 1304-010; 1304-015
Remove & Install Oil Pump
Start By:
a. remove oil pan
1. Remove oil supply tube (1) and suction bell and tube (2).
2. Remove bolts (3) that hold the oil pump to the cylinder block and remove oil pump (4).
3. To install, put oil pump (4) in position on the cylinder block. Install the bolts that hold the oil
pump to the cylinder block.
4. Put clean engine oil on the O-ring seals of the tubes.
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5. Install oil supply tube (1), suction bell and tube (2).
End By:
a. install oil pan
Disassemble Oil Pump
Start By:
a. remove oil pump
1. Remove the bolt and washer that hold the gear on the shaft.
2. Use Tool (A) and remove drive gear (1) from the shaft. Remove the key from the shaft.
3. Remove retainer (3) for the bypass valve. Remove the spring and the bypass valve.
4. Remove cover (2) from the pump body.
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5. Use Tool (B) and remove the bearings from the cover.
6. Remove gears (5) from pump body (4).
7. Use Tool (B) and remove the bearings from pump body (4).
Assemble Oil Pump
1. Use Tool (B) to install the bearings in the pump body. Install the bearings so the joint in the
bearings is 30 ± 15 degrees from the center line of the oil pump outlet passage (2).
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2. Install idler gear and drive gear (5) in the oil pump body (4). Put clean engine oil on the
bearings and the gears.
3. Use Tool (A) and install the bearings in cover (2). Install the bearings so the joint of the bearing
bores toward oil pump outlet passage (6).
4. Install bypass valve (7), spring (8) and the retainer.
5. Install the key on the shaft.
6. Install gear (1) on the shaft. Install the washer and bolt that hold the gear on the shaft. Be sure
the pump turns freely after assembly.
End By:
a. install oil pump
Mon Mar 29 18:16:24 UTC+0800 2021
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SENR64090034
Piston Cooling Tubes
SMCS - 1307-010
Remove & Install Piston Cooling Tubes
Start By:
a. remove oil pump
NOTE: The piston and connecting rod were removed for better illustration.
1. Remove bolts (1). Remove piston cooling tubes (2) from the engine. Use Tool (A) to turn the
crankshaft in a clockwise direction (as seen from the front of the engine) to get access to all of the
piston cooling tubes.
NOTE: The following steps are for the installation of the piston cooling tubes.
2. Check the alignment of the piston cooling tubes with Tool (B). See Use Of 5P8709 Tool Group
for Alignment Of Piston Cooling Jets, SMHS7267 for the correct alignment procedure.
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3. Install piston cooling tubes (2) on the engine. Use Tool (A) to turn the crankshaft clockwise (as
seen from the front of the engine) to get access for the installation of the piston cooling tubes.
End By:
a. install oil pump
Mon Mar 29 18:17:19 UTC+0800 2021
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SENR64090035
Pistons & Connecting Rod Assemblies
SMCS - 1225-017; 1225-011; 1225-012
Remove Pistons & Connecting Rod Assemblies
Start By:
b. remove oil pump
c. remove piston cooling tubes
1. Remove the carbon ridge from the top inside surface of the cylinder liners.
2. Turn the crankshaft until two pistons are at bottom center.
3. Remove bolts (1) and the bearing caps. Push the rods and pistons up until the rings are out of
the cylinder liners.
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4. Remove pistons (2) and connecting rods from the cylinder liners.
5. Do Steps 1 through 4 for the remainder of the pistons and connecting rods.
Install Pistons & Connecting Rod Assemblies
1. Put clean engine oil on piston rings, connecting rod bearings and cylinder liners.
2. Use Tool (A), and install piston (2) and the connecting rod in the cylinder liner.
3. Install the bearing cap on the connecting rod with the number on the side of the bearing cap on
the same side and same number as on the connecting rod.
4. Put 2P2506 Thread Lubricant on the threads of the bolts. Install the nuts, and tighten them to
a torque of 90 ± 8 N·m (67 ± 6 lb ft). Put a mark on the nuts and cap, and tighten the nuts an extra
90 ± 5 degrees.
5. Do Steps 1 through 4 for the remainder of the pistons and connecting rods.
End By:
a. install piston cooling tubes
b. install oil pump
c. install cylinder head assembly
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Disassemble & Assemble Pistons & Connecting Rod
Assemblies
Start By:
a. remove pistons and connecting rod assemblies
1. Remove bearings (3) from the connecting rod and connecting rod cap.
2. Remove retainer ring (1) with Tool (A).
3. Remove pin (2) and connecting rod (4) from the piston.
4. Remove piston rings (5) from the piston with Tool (B). Clean the piston ring grooves on the
pistons with an acceptable ring groove cleaning tool.
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NOTE: See, Use Of Piston Bearing Removal And Installation Tools, Special Instructions,
SMHS7295.
5. Heat connecting rod (4) in an oven to a temperature of 177° to 260°C (350° to 500° F). Never
use a direct flame to heat a connecting rod.
6. Put connecting rod (4) in position on the base plate of Tool (C). Put a new rod pin bearing (6)
on the adapter part of Tool (C).
NOTE: The old bearing is pushed out by Tool (C) as the new bearing is installed.
7. Use Tool (C) to push the new bearing into the connecting rod until the push adapter of Tool (C)
makes full contact with the connecting rod surface.
8. Use a pin boring machine to make the rod pin bearing the correct size. The bore in the new rod
pin bearing must be 50.830 ± 0.008 mm (2.0012 ± .0003 in).
9. Check the clearance between the ends of the piston rings. See the topic, "Pistons & Rings" in
Specifications Manual, SENR6470.
10. Install the oil ring spring in the oil ring groove of the piston.
NOTE: The oil ring is to be installed over the spring with the oil ring end gap 180° from the oil
ring spring joint.
11. Install the oil ring on the piston with tool (B).
12. Install the second (intermediate) piston ring with the side that has the identification "UP-2"
toward the top of the piston. Use Tool (B) to install the ring.
13. Install the first (top) piston ring with the side that has the identification "UP-1" toward the top
of the piston. Use Tool (B) to install the ring.
NOTE: After the installation of all three piston rings, put the piston rings in position so the end
gaps are 120 degrees apart.
14. Put the piston in position on connecting rod (4). Put clean engine oil on pin (2), and install the
pin. Install retainer rings (1) with Tool (A). Make sure the retainer rings are in the grooves of the
piston.
15. Install bearings (3) in the connecting rod and connecting rod cap.
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NOTE: Be sure the tabs in back of the bearings are in tab slots of the connecting rod and
connecting rod cap.
End By:
a. install pistons and connecting rod assemblies
Mon Mar 29 18:18:15 UTC+0800 2021
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SENR64090036
Cylinder Liners
SMCS - 1216-010
Remove & Install Cylinder Liners
Start By:
a. remove pistons and connecting rod assemblies
1. Put covers on the journals of the crankshaft for protection from dirt or water.
2. Remove the cylinder liners with Tool (A) as shown.
NOTE: The Caterpillar pack pulling tools can be used to remove the cylinder liner, piston and
connecting rod as a unit. For more detail, see Special Instruction, SEHS8554.
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3. To install, clean the cylinder liners and liner bores in the cylinder block.
4. Install cylinder liners (1) in the block without the O-ring seals or filler band.
5. To check the cylinder liner projection, see the topic, "Cylinder Liner Projection" in Systems
Operations Testing & Adjusting Manual SENR6471.
6. Remove the liner. Install new O-ring seals on the liners.
7. Put liquid soap on the O-ring seals and on the cylinder bores. Put the filler band in SAE 30W
Oil, then immediately install the filler band on the cylinder liner. Immediately install the cylinder
liner in the cylinder block with Tool (B) before expansion of the band.
End By:
a. install pistons and connecting rod assemblies
Mon Mar 29 18:19:11 UTC+0800 2021
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SENR64090037
Timing Gear Cover
SMCS - 1166-010
Remove & Install Timing Gear Cover
Start By:
a. remove water pump
b. remove governor and fuel pump drive
c. remove oil pan
d. remove crankshaft front seal and wear sleeve
e. remove engine front support
1. Remove governor and fuel pump drive covers to timing gear cover bolts (1).
2. Remove two fuel injection pump housing to timing gear cover bolts (2) and two plates to cover
bolts (3).
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3. Remove the five timing gear covers to cylinder block bolts and remove timing gear cover (4).
4. To install, be sure that O-ring seal (5) is in position in the timing gear plate as shown.
5. Put a new gasket in position and install timing gear cover (4) over the two dowel pins in the
cylinder block.
6. Install the bolts that hold the timing gear cover to the cylinder block. Cut the cover gasket to
make it even with the surface of the cylinder block and the bottom of the timing gear cover.
7. Install the bolts that hold the governor and fuel pump drive cover to the timing gear cover.
Install the fuel injection pump housing to timing gear cover bolts and the two plates to cover bolts.
End By:
a. install engine front support
b. install crankshaft front seal and wear sleeve
c. install oil pan
d. install governor and fuel pump drive
e. install water pump
Mon Mar 29 18:20:07 UTC+0800 2021
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SENR64090038
Timing Gears & Plate
SMCS - 1162-010; 1206
Remove & Install Timing Gears & Plate
Start By:
a. remove timing gear cover
b. remove fuel injection pump housing and governor
1. Remove four bolts (2), plate (3) and idler gear (1).
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2. If the camshaft is not going to be removed, use Tool (A) to remove camshaft gear (4).
NOTICE
Do not turn the crankshaft with the camshaft gear removed. Damage
can be caused to the pistons and valves or both.
3. Remove bolts (5) that hold timing gear plate (6) to the cylinder block.
4. Remove timing gear plate (6).
5. Use Tool (B) to remove the bearing from the idler gear.
NOTE: The following steps are for the installation of the timing gears and plate.
6. Install a new gasket on the timing gear plate.
7. Put timing gear plate (6) in position on the cylinder block and install the bolts that hold the
timing gear plate to the cylinder block.
8. Heat camshaft gear (4) to a maximum temperature of 205° C (400° F) for no longer than three
hours and install it on the camshaft.
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