Caterpillar Cat 994 Wheel Loader (Prefix 9YF) Service Repair Manual Instant Download.pdf

Service Repair Manual
Models
994 Wheel Loader

Shutdown SIS
Previous Screen
Product: WHEEL LOADER
Model: 994 WHEEL LOADER 9YF
Configuration: 994 Wheel Loader 9YF00001-UP (MACHINE) POWERED BY 3516 Engine
Disassembly and Assembly
994 WHEEL LOADER MACHINE SYSTEMS
Media Number -SENR4755-01 Publication Date -01/06/2004 Date Updated -10/06/2013
SENR47550017
Supplemental Steer Pump
SMCS - 4306-010; 4306-012; 4306-016
Remove & Install Supplemental Steer Pump
1. Remove steer diverter valve (1) See Remove & Install Steer Diverter Valve, in this module.
2. Remove hydraulic line (4) at the tip of the pump.
3. Attach a lifting device to pump (2) and remove two bolts (3). Remove supplemental steer pump
(2). The weight of the pump is 29 kg (65 lb).
NOTE: To install supplemental steer pump, reverse the removal steps.
Disassemble Supplemental Steering Pump
Start By:
a. remove supplemental steering pump
1. Clean the outside of the pump before it is disassembled.
NOTE: Put identification on all parts for correct position at assembly.
2. Remove the O-ring seal from the mounting flange of the pump.
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994 Wheel Loader 9YF00001-UP (MACHINE) POWERED BY 3516 Engine(SEBP19...
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3. Remove eight bolts (3) and flange (4) from the pump housing.
4. Remove O-ring seal (5) from flange (4).
5. Remove O-ring seals (6) and back-up rings (7) from support rings in the flange.
6. Remove two lip-type seals (8) and the spacer ring from the flange.
7. Remove isolation plates (9) and retainer assembly (10) from the pump housing.
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Typical Example
8. Remove pressure plate (11) from the pump housing.
Typical Example
9. Remove drive gear (12) and idler gear (13) from the pump housing.
10. Remove pressure plate (14) from the pump housing.
11. Remove isolation plates (15) and retainer assembly (16) from the pump housing with a seal
pick as shown.
12. Remove O-ring seals (17) and the back-up rings from the pump housing.
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Assemble Supplemental Steering Pump
1. Make sure all of the parts of the hydraulic pump are clean and free of dirt and foreign material
before the pump is assembled.
NOTE: See Diagnosing Tyrone Gear Pump Failures, Form No. FEG45137, for assistance in
inspection of the parts.
2. Inspect all parts of the pump. Check the bores in the pump body. Measure the depth of grooves
(1) in each bore. If the grooves are deeper than 0.38 mm (.015 in), a replacement of the pump
body and gears must be made.
3. Photo illustration A70543P1 shows how retainer assembly (3), isolation plates (4), back-up
rings (5) and O-ring seals (6) are to be installed.
NOTICE
There are two isolation plates needed in the bottom of the pump
housing and two in the top. The isolation plates hold the seal
components in place. The isolation plates with the round edges on the
outer radius on one edge go in the bottom of the pump housing with
the round edge down. The isolation plates with the straight (square)
edges on the radius go next to the top flange.
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4. Install back-up rings (5) and O-ring seals (6). Install retainer assembly (3). Install isolation
plates (4) with the rounded edges down.
Typical Example
5. Install pressure plate (7) in its original position with the bronze surface of the pressure plate
toward the gears in the pump.
Typical Example
6. Install idler gear (9) and drive gear (8) in the pump housing.
Typical Example
7. Install pressure plate (10) in its original position with the bronze surface of the pressure plate
toward the gears in the pump.
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8. Install seal (11) in the flange with tooling (A). Install the seal with the lip of the seal toward the
inside of the pump.
9. Install spacer (12).
10. Install seal (13) in the flange with tooling (A). Install the seal with the spring loaded lip toward
the inside of the pump.
11. Put a thin layer of 1P808 General Purpose Lubricant on the seals, retainer assemblies and
isolation plates to hold them in place.
12. Install back-up rings (14) and O-ring seals (15) on flange (19). Install retainer assembly (18).
Install isolation plates (16) with the straight (square) edge toward the flange.
13. Install O-ring seal (17) on the flange.
Typical Example
14. Install flange (19) on the pump housing.
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Typical Example
NOTE: Disregard manifold (22). The supplemental steer pump will have manifold (22).
15. Install eight bolts (20) that hold the flange to the pump housing. Tighten the bolts to a torque
of 237 ± 14 N·m (175 ± 10 lb ft).
16. Install new O-ring seal (23) on the flange.
End By:
a. install supplemental steering pump.
Copyright 1993 - 2020 Caterpillar Inc.
All Rights Reserved.
Private Network For SIS Licensees.
Fri Mar 20 08:57:31 UTC+0800 2020
7/7
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Shutdown SIS
Previous Screen
SENR47550018
Steering Control Valve
SMCS - 4307-010; 4307-015; 4307-016
Remove & Install Steering Control Valve
Start By:
a. connection of anti-pivot link
1. Drain the oil level in the hydraulic tank below the height of the steering control valve.
NOTE: Cap and plug all hydraulic lines and fittings as they are removed to prevent excess fluid
loss and contamination.
2. Put identification on the oil lines for correct installation. Disconnect the oil lines (1) and tube
(2) from the steering control valve.
3. Remove two hydraulic lines from block (3). Remove hydraulic line (4).
4. Remove bolts (8) and move the hydraulic line away from the valve.
5. Remove eight bolts (6) and move manifold (7) away from the valve.
6. Remove the three bolts that fasten the valve to its mounting bracket and remove steer control
valve (5). The weight of the steer control valve is 39 kg (85 lb).
1/6
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NOTE: To install steer control valve, reverse the removal steps.
End By:
Disassemble Steering Control Valve
Start By:
a. remove steering control valve
Typical Example
1. Remove plug (4), the seal, spring (2) and valve (1) from cover (5).
2. Remove shims (3) from the plug.
3. Remove the bolts that hold cover (5) in position. Remove the cover from the body.
Typical Example
4. Remove seat (6) and the seal from the cover. Check the condition of the seals in the cover. If
the seals have damage use new parts for replacement.
Typical Example
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5. Remove spring (9), spring (8) and valve (7) from the body.
6. Remove valve stem assembly (10) from the body.
7. Disassemble stem assembly (10) as follows:
Typical Example
a. Remove bolts (14) the lockwasher and washer from the stem.
b. Remove retainer (13), spring (12) and spacer (11).
c. Remove retainer (17) and shims (16) from valve stem (15).
8. Remove plug (18) and the O-ring seal from the body.
9. Remove seat (19) and the O-ring seal from the body. Check the condition of the seal on the seat.
If the seal has damage, use new parts for replacement.
10. Remove the ball seat and seal from the body. Check the condition of the seal on the seat. If the
seal has damage, use new parts for replacement.
3/6
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Typical Example
11. Remove stop assembly (20) from the body.
NOTE: Disregard item (21). The steer control valve will not have item (21).
12. Remove the three bolts and cover (22) and the seal from the body.
Assemble Steering Control Valve
1. Make sure all of the parts of the steering control valve are clean and free of dirt and foreign
material.
2. Put clean hydraulic oil on all the parts.
3. Install stop assembly (4) and the seal in the body.
Typical Example
4. Install cover (5) and seal (6). Install the three bolts that hold the cover in position.
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Typical Example
5. Install the ball in seat (7). Install the seat and O-ring seal in the body.
6. Install the seat, O-ring seal and plug in the body.
7. Assemble the valve stem assembly as follows:
a. Put shims (11) in position in valve stem (9).
b. Install retainer (12), spacer (13), spring (14) and retainer (8).
c. Install the washer, lockwasher and bolts (10) that hold the unit together.
Typical Example
8. Install valve stem assembly (19) in the valve body as shown.
9. Install valve (15), spacers (16), spring (17) and spring (18) in the valve body.
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10. Install the O-ring seal and seat (20) in the cover as shown.
Typical Example
11. Put cover (21) in position on the valve body. Install the bolts that hold it.
Typical Example
12. Install valve (22), spring (23) and plug (24) in the valve body.
End By:
a. install steering control valve
Fri Mar 20 08:58:18 UTC+0800 2020
6/6
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Shutdown SIS
Previous Screen
SENR47550019
Steering Neutralizer Valve
SMCS - 4330-010; 4330-017
Remove & Install Steering Neutralizer Valve
Start By:
To prevent possible bodily injury, make sure all of the pressure is
released from the hydraulic system. Remove the cap from the hydraulic
tank to release the pressure.
NOTE: There are two steering neutralizer valves. The location of the valves is at the top of the
pivot area.
1. Remove the cap from the hydraulic tank. Put identification on all hose or lines that are to be
disconnected.
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NOTE: Cap and plug all hydraulic lines and fittings as they are removed to prevent excess fluid
loss and contamination.
2. Disconnect three hydraulic lines (2) from the neutralizer valve.
3. Remove two bolts (1) from the neutralizer valve and remove the neutralizer valve.
NOTE: To install steering neutralizer valve, reverse the removal steps.
End By:
a. separation of anti-pivot link
Disassemble & Assemble Steering Neutralizer
Start By:
a. remove steering neutralizer valve
1. Remove plug assembly (3), spring (2) and ball (1) from the body.
2. Check the O-ring seal on the plug assembly for damage. If the part has damage, use a new part
for replacement.
3. Remove boot (4) from the body.
4. Remove plug (5) from the body. Check the O-ring seal on the plug for damage. If the part has
damage, use new parts for replacement.
2/3
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5. Remove spring (8) and stem (7) from the body.
NOTE: On assembly, use driver group (A) to install the lip-type seal.
6. Remove the seal from body (6).
NOTE: To assemble the steering neutralizer, reverse the disassembly steps.
End By:
a. install steering neutralizer valve
Fri Mar 20 08:59:06 UTC+0800 2020
3/3
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Shutdown SIS
Previous Screen
SENR47550020
Steer Pumps
SMCS - 4306-010; 4306-017
Remove & Install Steer Pumps
NOTE: Component location is at the top of the rear pump drive. The procedure for removing the
pumps is similar for both pumps.
1. Remove the cap from the steer hydraulic tank to relieve the pressure in the system.
NOTE: Cap and plug all lines and fittings as they are removed to prevent excess fluid loss and
contamination.
2. If the left steer pump is to be removes, remove brake cooling pump (3), See Remove & Install
brake Cooling Pump, in this module.
3. Remove all hydraulic lines that are connected to the steer pump.
Contact Caterpillar Service Technology Group for a proper lifting
device to remove the steer pumps. The use of an improper lifting device
may result in personal injury.
1/10
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4. Attach a lifting device to steer pump (2). Remove four bolts (1) and remove the pump. The
weight of the steer pump is approximately 159 kg (350 lb).
NOTE: To install steer pumps, reverse the removal steps.
Disassemble & Assemble Steer Pumps
Start By:
a. remove steer pump
NOTE: Place orientation marks on the pump housings to aid in proper assembly of the pump.
1. Place the pump on a clean work bench. Position the pump on its side with the valve group (1)
facing up.
2. Remove valve group (1). Remove four bolts (2) and cover (3).
3. Disassemble valve group (1) as follows:
NOTICE
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Do not remove the screw or locknut from valve (4) unless it is
necessary. If it is necessary to remove the screw, mark its position so
that it may be installed in its original position.
a. Remove valve (4), spacer (5), spring (6), spacer (7) and spool (8). Remove the O-ring seal from
valve (4).
b. Repeat Step 3a on the remaining valve. There will be two springs instead of one behind the
remaining valve.
NOTICE
When the spacers are removed in the following Step, identify which
ones were on the bottom and top of impeller (11).
4. Remove retaining ring (9) and seal (10). Remove retaining ring (12) and the spacers behind the
retaining ring. Remove impeller (11). Remove key (13). Remove the retaining ring and spacers
from behind the impeller.
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5. Remove head group (17). Remove piston (16), spring (15), and rod (14). Remove rod (18),
piston (19) and spring (20). Remove O-ring seal (21).
6. Remove bearing (22). Remove port plate (36). Remove minimum and maximum displacement
stops (23). Remove four bolts (26) and two retainers (24). Remove barrel (25) with the pistons.
4/10
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7. Remove ring (29) and washers (30). Mark the location of the swashplate and cradle bearings in
relation to the cradle. Remove swashplate (27) and bearings (28).
8. Remove retaining ring (31) and shaft cover with seal (32). Remove shaft and bearing (33).
Replace the bearing on the shaft, if necessary.
5/10
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