Caterpillar Cat 12G Motor Grader (Prefix 61M) Service Repair Manual (61M12027 and up).pdf

Service Repair Manual
Models
Caterpillar Cat 12G
Motor Grader

start by:
a) remove differential
1. Bend the lock away from nut (1) and loosen nut (1) with tool (A).
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12G Motor Grader 61M12027-UP (MACHINE) POWERED BY 3306 Engine(SEBP1...
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2. Remove nut (1), lock (3) and washer (2).
3. Put the differential and the carrier in position as shown.
4. Remove wire (5) from the nuts on each side of the differential. Remove nuts (8).
5. Bend the locks away from bolts (6). Remove the bolts, the locks and locks (7) from the cap.
6. Remove cap (4) from the carrier.
7. Remove the dowel that holds the small cage in alignment with the cap.
8. Fasten a hoist and a strap to the differential (9) as shown. Lift the differential and remove it
from the carrier. Weight is 240 lb. (109 kg).
3/13
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9. Remove the ring and seal (10) from the carrier.
10. Remove small cage (11) from the differential. Remove the nut and the bearing cup from the
cage.
11. Remove bearing (12) from housing (14) with tooling (B).
12. Remove bolts (13) and the washers that hold housing (14) to the clutch housing. Remove
housing (14). Remove the brass washer from the inner face of housing (14).
13. Remove gear (15) from the spider gears.
14. Remove spider (18) and the gears and washers from the clutch housing.
15. Remove brass washers (16) and gears (17) from the spider.
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16. Remove the brass bearings from the gears with tooling (C).
17. Remove gear (19) from the housing.
18. Turn the bevel gear, clutch housing and the piston housing over.
19. Remove cage (20). Remove the nut, the bearing cup, the ring and the two seals from cage (20).
20. Remove bolts (21) and the washers that hold piston housing (22) to the bevel gear and the
clutch housing. Remove piston housing (22).
21. Remove bearing (23) from the piston housing with tooling (B).
22. Turn the piston housing over.
5/13
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23. Remove brass washer (24) and piston (25) from the piston housing. Remove the two seals
from the piston.
24. Remove discs (26) and disc assemblies (27) from the clutch housing.
25. Remove the pressure disc from the housing.
26. Remove pinion (28) from the carrier with tooling (D).
27. Remove bearing cups (29) and (31) from the carrier with a punch and a hammer.
28. Remove seal (30) from the carrier.
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29. Remove bearing (32) from the pinion with tooling (E).
Assemble Differential (Unlocking)
1. Heat bearing (2) in oil to a temperature of 275° F (135° C). Install bearing (2) on pinion (1).
2. Lower the temperature of the two bearing cups for the pinion. Install the bearing cups in
differential carrier (3).
7/13
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3. Install the seal in the differential carrier. Install the seal with the lip toward the bevel gear. Put a
small amount of oil on the lip of the seal.
4. Put pinion (1) in position on a block as shown. Install tooling (A) on carrier (3) and fasten a
hoist to tooling (A). Lift the carrier and put it in position over pinion (1) so bearing (2) is in its seat
in the bearing cup.
5. Heat bearing (4) in oil to a temperature of 275° F (135° C).
6. Install bearing (4) on pinion (1). Make sure the bearing is in its seat in the bearing cup. Lift the
carrier and remove the block from under the pinion. Put the carrier on the floor. Remove tooling
(A) from the carrier.
7. Install the washer, the lock and nut (5) on the pinion. Do not tighten the nut.
8. Put two .250 in. (6.35 mm) dowels in the splines of the pinion. Put the dowels in position 180°
apart. Install tooling (B) over the pinion and the dowels.
9. Check the amount of torque needed to move the pinion without any preload on the pinion
bearings. Remove the torque wrench from tooling (B).
10. Install a ratchet on tooling (B).
8/13
2021/2/9

11. Install tool (C) on nut (5). Tighten nut (5) with tool (C) while holding the pinion with the
ratchet. Tighten the nut enough to get a torque of 6 ± 4 lb. in. (6.9 ± 4.6 cm.kg) more than the
torque needed to turn the pinion when the bearings were not preloaded. Remove tooling (B) and
(C).
12. Put clutch housing (7) in position on the floor as shown. Put a block of wood 2 1/2in. (63.5
mm) high in the center of the housing. Put gear (6) in position on the block.
13. Put the pressure disc in position in clutch housing (7). Install the eight discs and the seven disc
assemblies in the housing starting with a disc.
NOTE: Put clean SAE 30 oil on the discs and disc assemblies (8) at installation.
14. Put the large brass washer on the face of gear (6). Make sure the hole in the washer is in
alignment with the dowel in the housing.
15. Install the seals on the outside and the inside of the piston. Install the seals so the lips are
toward the bottom of the bore for the piston in the piston housing. Put some clean SAE 30 oil on
the lips of the seals. Install the piston in housing (10).
16. Heat bearing (9) in oil to a temperature of 275° F (135° C). Install bearing (9) on the hub of
piston housing (10).
17. Put piston housing (10) and the bevel gear in position on clutch housing (7). Make sure the
holes in both housings and the bevel gear are in alignment.
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18. Install three 5/8"-11 NC forged eyebolts (12) in piston housing (10). Install the bolts and the
washers that hold the piston housing to the bevel gear and the clutch housing. Put a bar in position
as shown in the eyebolts. Tighten bolts (11) to a torque of 185 ± 10 lb. ft. (25.6 ± 1.4 mkg).
19. Remove the bar and the eyebolts.
20. Turn the housings and the bevel gear over. Be careful that gear (6) does not fall out.
21. Install the brass bearings in spider gears (14) with tool (E) and an arbor press.
22. Install gears (14) and brass washers (16) on spider (15). Put the spider and the gears in position
on the clutch housing as shown.
NOTE: Make sure the notches in the brass washers are up.
23. Install gear (13) as shown on the spider gears. Install the large brass washer on the face of gear
(13). Make sure the hole in the washer is in alignment with the dowel in the housing.
24. Put housing (18) in position on the clutch housing. Tool (F) can be used to make sure the
notches in washers (16) are in alignment with the dowels in housing (18). Install bolts (19) the
washers. Tighten the bolts to a torque of 60 ± 5 lb. ft. (8.3 ± 0.7 mkg).
25. Heat bearing (17) in oil to a temperature of 275° F (135° C). Install bearing (17) on the hub of
housing (18).
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12G Motor Grader 61M12027-UP (MACHINE) POWERED BY 3306 Engine(SEB...
2021/2/9

26. Install the bearing cup and nut (22) in cage (20). Install ring (23) and the two seals on the cage.
27. Put the cage in position over the bearing.
28. Install the nut and the bearing cup in cage (21). Put cage (21) in position over the bearing.
29. Fasten a hoist and a strap to the differential. Put the differential in position on the carrier.
Install the ring and seal between the carrier and cage (20). Make sure the opening in the cage is in
alignment with the ring and seal.
30. Put cap (24) in position over the studs in the carrier. Install the dowel in cage (21). Make sure
the dowel is in alignment with the hole in cap (24).
31. Install nuts (26) that hold the cap to the carrier. Tighten the four nuts to a torque of 75 lb. ft.
(10.4 mkg).
32. Put the differential in position as shown. Put tooling (D) in position on the differential and
against a tooth on the bevel gear. Turn the bevel gear to measure the gear clearance (backlash)
between the pinion and the bevel gear.
33. Make an adjustment to nut (22) under the bevel gear with tool (C), while keeping nut (25)
finger tight against the top bearing, to get a gear clearance (backlash) of .008 ± .002 in. (0.20 ±
0.05 mm).
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34. Loosen nut (25). Tighten the nut by hand to remove the end play. Tighten nut (25) 1 to 1 1/2
notches and measure the amount of change in dimension (X) with tooling (D). Dimension (X)
must change by .005 ± .002 in. (0.13 ± 0.05 mm).
35. Tighten nuts (26) to a torque of 280 ± 20 lb. ft. (38.8 ± 2.8 mkg). Turn the differential and
measure the gear clearance (backlash) again.
36. Put locks (27) in position on the cap. Install the locks and bolts that hold locks (27). Bend the
locks against the bolts. Install wires (28) through the studs and nuts on each side of the
differential.
37. Install all the O-ring seals on the differential.
end by:
a) install differential
12/13
2021/2/9

Copyright 1993 - 2021 Caterpillar Inc.
All Rights Reserved.
Private Network For SIS Licensees.
Tue Feb 9 01:26:57 UTC+0800 2021
13/13
2021/2/9

Shutdown SIS
Previous Screen
Product: MOTOR GRADER
Model: 12G MOTOR GRADER 61M
Configuration: 12G Motor Grader 61M12027-UP (MACHINE) POWERED BY 3306 Engine
Disassembly and Assembly
12G, 130G & 140G MOTOR GRADER POWER TRAIN
Media Number -SENR7186-01 Publication Date -01/11/1989 Date Updated -24/02/2006
SENR71860015
Differential (Direct Drive)
SMCS - 3258-16; 3258-15
1/11
2021/2/9

Disassemble Differential (Direct Drive)
2/11
2021/2/9

start by:
a) remove differential
1. Remove all the O-ring seals from the differential. Bend the lock away from nut (1) and remove
nut (1) with tool (A).
3/11
2021/2/9

2. Remove lock (2) and washer (3) from the shaft.
3. Put the differential in position with the bevel gear up as shown.
4. Remove wire (7) from each side of the differential. Remove nuts (6) that hold the cap to the
carrier.
5. Remove bolt (4) from each side of the differential.
6. Remove lock (5) from each side of the differential.
7. Remove cap (8) from the carrier.
8. Remove dowel (9) from each of the cages on the differential.
9. Fasten a hoist and a strap to the differential.
4/11
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10. Remove differential (10). Weight is 160 lb. (73 kg).
11. Remove cages (11) and (12). Remove the nuts and the bearing cups from the cages.
13. Remove bearing cone (13) with tooling (B).
14. Turn the differential on its other end. Put it on blocks as shown. Remove bolts (14) and the
washers that hold the hub and the bevel gear to the other hub.
5/11
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15. Install three 5/8"-11 NC forged eyebolts in hub (17) as shown. Fasten a hoist to eyebolts (15).
16. Remove hub (17) from the bevel gear. Remove the bevel gear from the other hub.
17. Remove bearing cone (16) from hub (17) with tooling (B).
18. Remove pinion (18) from the differential carrier with tooling (C).
19. Remove bearing cups (20) and (21) from the differential carrier.
20. Remove seal (19) from the differential carrier.
21. Remove bearing cone (22) from pinion (18) with tooling (D).
6/11
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Assemble Differential (Direct Drive)
1. Heat bearing (2) in oil to a temperature of 275° F (135° C). Install bearing (2) on pinion (1).
2. Lower the temperature of the two bearing cups for the pinion. Install the bearing cups in
differential carrier (3).
3. Install the seal in the differential carrier. Install the seal with the lip toward the bevel gear. Put a
small amount of oil on the lip of the seal.
4. Put pinion (1) in position on a block as shown. Install tooling (A) on carrier (3) and fasten a
hoist to tooling (A). Lift the carrier and put it in position over pinion (1) so bearing (2) is in its seat
in the bearing cup.
7/11
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6. Install bearing (4) on pinion (1). Make sure the bearing is in its seat in the bearing cup. Lift the
carrier and remove the block from under the pinion. Put the carrier on the floor. Remove tooling
(A) from the carrier.
7. Install the washer, the lock and nut (5) on the pinion. Do not tighten the nut.
8. Put two .250 in. (6.35 mm) dowels in the splines of the pinion. Put the dowels in position 180°
apart. Install tooling (B) over the pinion and the dowels.
9. Check the amount of torque needed to move the pinion without any preload on the pinion
bearings. Remove the torque wrench from tooling (B).
10. Install a ratchet on tooling (B).
11. Install tool (C) on nut (5). Tighten nut (5) with tool (C) while holding the pinion with the
ratchet. Tighten the nut enough to get a torque of 6 ± 4 lb. in. (6.9 ± 4.6 cm.kg) more than the
torque needed to turn the pinion when the bearings were not preloaded. Remove tooling (B) and
(C).
8/11
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13. Install bearing (6) on hub (7).
14. Heat bearing (9) in oil to a temperature of 275° F (135° C). Install the bearing on hub (10).
15. Put hub (7) in position on blocks with its bearing down. Put bevel gear (12) in position on hub
(7). Install three 5/8"-11 NC forged eyebolts in hub (10). Fasten a hoist to eyebolts (8). Put the hub
in position on the bevel gear. Remove the hoist.
16. Install bolts (11) and the washers that hold the hub and the bevel gear to hub (7). Tighten the
bolts to a torque of 185 ± 10 lb. ft. (25.6 ± 1.4 mkg).
17. Remove the eyebolts from the differential.
18. Install the bearing cups and nuts (13) in cages (14). Put the cages in position on the hubs.
19. Fasten a hoist and a strap to the differential.
20. Lift the differential and put it in position on the carrier. Remove the hoist and the strap.
NOTE: Make sure the holes in the cages are up.
9/11
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21. Install dowels (16) in the cages.
22. Put cap (15) in position on the cages and the studs. Make sure the dowels in the cages are in
alignment with the holes in the cap.
23. Install nuts (17) that hold the cap to the carrier. Tighten the nuts to a torque of 75 lb. ft. (10.4
mkg).
24. Put the differential in position as shown. Put tooling (D) in position on the differential and
against a tooth on the bevel gear. Turn bevel gear (12) to measure the gear clearance (backlash)
between the pinion and the bevel gear.
10/11
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25. Make an adjustment to the nut under the bevel gear with tool (C), while keeping nut (18)
finger tight against the top bearing, to get a gear clearance (backlash) of .008 + .004 - .003 in.
(0.20 + 0.10 - 0.08 mm).
26. Loosen nut (18). Tighten the nut by hand to remove the end play. Tighten nut (18) 1 1/2 to 2
notches and measure the amount of change in dimension (X) with tooling (D). Dimension (X)
must change by .005 ± .002 in. (0.13 ± 0.05 mm).
27. Tighten nuts (17) to a torque of 280 ± 20 lb. ft. (38.8 ± 2.8 mkg). Turn the differential and
measure the gear clearance (backlash) again.
28. Put locks (20) in position on the cap. Install the locks and bolts (19) that hold the locks. Bend
the locks against the bolts.
29. Install wires (21) on the studs on each side of the differential.
30. Install all the O-ring seals on the differential.
end by:
a) install differential
Copyright 1993 - 2021 Caterpillar Inc.
All Rights Reserved.
Private Network For SIS Licensees.
Tue Feb 9 01:27:53 UTC+0800 2021
11/11
2021/2/9

Shutdown SIS
Previous Screen
Product: MOTOR GRADER
Model: 12G MOTOR GRADER 61M
Configuration: 12G Motor Grader 61M12027-UP (MACHINE) POWERED BY 3306 Engine
Disassembly and Assembly
12G, 130G & 140G MOTOR GRADER POWER TRAIN
Media Number -SENR7186-01 Publication Date -01/11/1989 Date Updated -24/02/2006
SENR71860016
Transmission
SMCS - 3150-12; 3150-15; 3150-16; 3150-11; 3159-15; 3159-16
Remove Transmission
start by:
a) remove fuel tank
b) remove alternator
c) remove fan drive
d) remove transmission oil filter base
e) remove transmission oil and scavenge pump
f) remove parking brake rotochamber and release valve
1. Drain the oil from the transmission. Drain the coolant from the cooling system.
NOTE: The plug that has a location in tube (4) toward the front of the machine can be removed to
drain the coolant from tube (4). Put the plug in position in tube (4) after draining the coolant.
2. Remove hose clamps (1) from each end of tube (4). Remove tube (4).
1/41
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3. Put identification on oil lines (3) as to their location on the relief control valve. Disconnect oil
lines (3) from the valve.
4. Loosen the nuts from bolts (2) on each side of the engine. Tighten bolts (2) until they are
against the frame. Tighten the nuts.
5. Remove bolts (6) and retainer (9) that hold couplings (8) to the transmission. Loosen nuts (7)
and slide couplings (8) free of the transmission. Lift control cables (5) out of the links on the
transmission control valves.
6. Fasten a hoist to the lifting eyes on the transmission. Remove bolts (10) that hold the
transmission to the flywheel housing. Remove nuts (11) that hold the transmission to the studs in
the differential housing.
7. Move the transmission away from the engine and off the studs in the differential housing.
8. Lift transmission (12) and remove it from the machine. Weight is 1500 lb. (680 kg).
Install Transmission
2/41
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1. Fasten a hoist to the lifting eyes on the transmission. Lower the transmission (1) into position in
the machine.
2. Move the transmission on to the studs in the differential housing and into the flywheel housing.
NOTE: To put the splines on the transmission adapter in alignment with the flywheel, turn the
transmission oil pump shaft. To put the splines in the transmission in alignment with the splines
on the differential input shaft, the following procedure can be used:
a) Drain the oil from the tandem housings.
b) Remove the axles.
c) Turn the differential input shaft with a prybar or a screwdriver while the transmission is being
installed on the studs of the differential housing.
d) Install the axles and fill the tandem housings with oil to their correct levels.
3. Install bolts (2) that hold the transmission to the flywheel housing. Install the nuts that hold the
transmission to the differential housing. Connect oil lines (3) to their correct locations on the relief
control valve. Remove the hoist.
4. Put three control cables (7) in position on the valve links. Put couplings (6) in position in the
transmission housing. Tighten nuts (4) against the couplings. Put retainer (5) in position over the
couplings. Install the bolts that hold the retainer to the transmission housing.
3/41
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5. Put tube (8) in position on the machine. Tighten hose clamps (9) at each end of tube (8) over the
tube. Loosen the nuts on bolts (10) on each side of the machine. Move bolts (10) away from the
frame. Tighten the nuts.
6. Fill the transmission with oil to its correct level. Fill the cooling system with coolant to its
correct level.
end by:
a) install parking brake rotochamber and release valve
b) install transmission oil and scavenge pump
c) install transmission oil filter base
d) install fan drive
e) install alternator
f) install fuel tank
Disassemble Transmission
start by:
4/41
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a) remove transmission
1. Install the transmission on tooling (C). Remove bolts (1) and the lockwashers that hold the
cover to the transmission. Remove cover (2).
2. Remove links (3) from the transmission hydraulic control valves.
3. Remove bolts (8) and plates (7). Move the four sleeves (5) free of the transmission hydraulic
control valves.
NOTE: Do not remove bolts (4) and (6) at this time. Bolts (4) and (6) hold the control valves to
the transmission.
4. Install a 3/8"-16 NC forged eyebolt in the transmission case. Install tooling (B) in the eyebolt.
5/41
2021/2/9

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5. Install tooling (A) on the transmission case and on the control valves. Connect tooling (B) to
tooling (A) as shown. Remove bolts (4) and (6). Remove transmission hydraulic control valves (9)
with tooling (B). Weight is 90 lb. (41 kg). See DISASSEMBLE HYDRAULIC CONTROL
VALVES for disassembly of the control valves.
6. Remove the four sleeves from the transmission. Fasten tooling (D) to the lifting eyes on top of
the transmission. Remove the bolts that hold the transmission to tooling (C). Remove the bolts and
cover (10).
7. Install two 1/2"-13 NC forged eyebolts and two nuts in the transmission on top of the output
flange. Fasten tooling (D) to the two eyebolts.
8. Turn the transmission on its end with tooling (D). Put the transmission in position on tooling
(E). Remove tooling (D) and the eyebolts.
9. Remove O-rings (11) and O-ring (12) from the housing.
10. Remove bolt (13) and bolt (14) that hold the planetary transmission in the transmission case.
11. Install two 5/8"-11 NC forged eyebolts (15) in the housing. Fasten a hoist to the eyebolts.
12. Remove the planetary transmission from the transmission case. Weight is 560 lb. (254 kg).
13. Put the transmission on three blocks.
6/41
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Make sure the input gear for the planetary transmission is on top of the
blocks. If the input gear is not on top of the blocks, other components
can fall out the bottom of the transmission when a retaining ring is
removed.
14. Remove bolts (16). Remove O-ring seal (18). Lift housing (17) enough to remove springs (19)
and plungers (20). Remove the housing. Weight is 85 lb. (39 kg). Remove the O-ring seal that is
under the flange on housing (17).
15. Remove bolts (22). Bend the locks (23) away from bolts (21). Remove bolts (21) and locks
(23).
16. Remove hub (25). Remove four discs (24) and three plates (26). These discs and plates are for
the parking brake clutch.
7/41
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17. Install tooling (F) as shown against plate (29). Put springs (28) in compression with tooling (F)
and a press.
18. Remove retaining ring (27). Slowly release the compression on springs (28). Remove tooling
(F). Remove the plate and the springs.
19. Remove cage (30) from the hub. Remove O-ring seal (31) and the internal ring that is under
the O-ring seal.
20. Remove external ring (32) from the hub.
21. Remove piston (34).
22. Remove ring gear (33).
8/41
2021/2/9

Caterpillar Cat 12G Motor Grader (Prefix 61M) Service Repair Manual (61M12027 and up).pdf

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Caterpillar Cat 12G Motor Grader (Prefix 61M) Service Repair Manual (61M12027 and up).pdf