Gradall XL4000 User manual

July, 2002
EXCAVATOR TECHNICAL
MANUAL
GRADALL
406 Mill Avenue, S.W.
New Philadelphia, OH, 44663, USA
Telephone: [phone]
Fax: [phone]
VOLUME 2
2460-4144
XL4000 Starting
S/N 0415225/0428225
XL5000 Starting
S/N 0518110/0526110

HYDRAULIC EXCAVATORS
GRADGRAD
GRADGRAD
GRADALLALL
ALLALL
ALL
®
Form No. 29703
Issued 8/98

The following symbols are used to call your attention to softly notices:
This symbol indicates an extreme hazard which would result in high probability of death or serious injury
if proper precautions are not taken.
This symbol indicates a hazard which could result in death or serious injury if proper precautions are not taken.
This symbol indicates a hazard which could result in injury or damage to equipment or property if proper
precautions are not taken.
I. Introduction
Read and understand this Manual, along with the appropriate Upperstructure and Carrier Owner /Operator Manual, EMI Excavator Safety
Manual, CIMA DUMPER Safety Manual, Gradall Hydraulic Excavator Safety Manual and all instructional decals and plates before starting,
operating or performing maintenance procedures on this equipment. Keep operator and safety manuals in cab.
!!
!!
!DANGER
!!
!!
!WARNING
!!
!!
!CAUTION
Read and understand all manuals listed above. Be sure you are familiar with machine response to controls.
Read and understand all material relating to the circuit to be checked. Be sure you understand circuit to be checked.
Always relieve trapped pressure before opening or disconnecting any portion of a hydraulic circuit. Oil at operating temperature can
cause serious burns. Oil released at operating temperature, as well as trapped pressure, can cause serious injury or death.
If you are working with a helper, be sure they understand the procedure. Be certain each of you knows what to expect from the other
and when to expect it. Make sure each of you knows where the other is at all times.
Be sure you understand all steps of the procedure before testing and/or adjusting any circuit. Follow the procedure carefully.
Always wear safety glasses when performing testing and adjusting procedures.
Clean up oil spills immediately. Slippery surfaces can cause serious accidents.
Always make sure engine RPM is correct before performing testing and adjusting procedures.
Always make sure hydraulic oil level in reservoir is correct and that oil is at normal operating temperature before testing
and adjusting circuits.
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Safe operation depends on reliable equipment and proper operating procedures. Performing the checks and services described in this Manual will keepyour
GRADALL XL 4100/XL 5100 Excavator in reliable condition. Use of the recommended operating procedures can help you avoid accidents.Because some procedures may
be new to even the experienced technician, we recommend that this manual be read, understood and followed by all who service this unit. ! DANGER, ! WARNING
and ! CAUTION notes in this Manual will help you avoid injury and damage to the equipment. These notes are not intended to cover all eventualities. It is
impossible to anticipate and evaluate all possible applications and methods of operation for this equipment. Any procedure not specifically recommended by
GRADALL must be thoroughly evaluated from the standpoint of safety before it is placed in practice. If you are not sure, contact your GRADALL Distributor before
operating. Do not modify this machine without written permission from GRADALL.
Testing & Adjusting Precautions
Form No. 29703
Important Safety Notice

Hydraulic System:
The XL 4100 and XL 5100 Remote Control Gradall Hydraulic System is designed for efficient operation with a
minimum amount of wear to related system components. Air from an electric compressor and from the engine
intake manifold pressurizes the hydraulic system to 6-8 PSI. A 120 PSI backpressure valve is located in the main
control valve banks return line. These features ensure fluid is always present to components when required.
DO NOT OPEN the hydraulic reservoir without relieving air pressure. Serious injury could result from being
sprayed with hot hydraulic fluid. Hydraulic fluid temperature is controlled by a cooler circuit which maintains the
fluid temperature approximately 100° above ambient temperature. Individual hydraulic components and circuitry
will be explained in this Manual.
The primary circuits of the GRADALL XL Series Crawler -Mounted Excavator are as follows:
Main pump: Work circuits whose fluid is supplied by the main hydraulic pumps
Pilot Pump: Control circuits whose fluid is supplied by the pilot pump
Recirculating Pump: Cooling circuit directing a constant flow of fluid through the cooler
Swing Pump: Closed loop circuit separate from the main pump circuit
Hydraulic fluid: Use only specified hydraulic fluid in the Gradall. Use of fluids other than those which meet
specifications will seriously damage the hydraulic components, resulting in expensive failure or machine
downtime. Approved fluids are: Hydraulic Oil: M
bilfluid®424 or Citgo Tractor Hyd. Fluid #33310.
Fire-Resistant Fluid: Quaker Chemical Quintolubric 822-300. Do Not use any other fluid without first
receiving approval from your GRADALL Distributor or the GRADALL factory. Fluid specifications are listed in the
lubrication chart on your machine and the decal on the fluid reservoir of the upperstructure.
Add additional fluid through the main reservoir return filter when topping up the system. If the reservoir has
been drained, follow START-UP PROCEDURE. See Section VII, Main Hydraulic Pump.
Hydraulic System logic is determined by the following: Load Sense Control which regulates standby pressure.
High Pressure Cutoff which senses pressure above 5000 PSI then reduces pressure by destroking the pump.
Horsepower Control which does not let the engine draw down below 1900 RPM when all circuits are activated
at the same time.
If repairs or adjustments to the hydraulic system become necessary, we recommend you contact your GRADALL
Distributor to have this work done by a qualified GRADALL technician.
See Appendix B & Appendix C for circuit operating times.
II. Hydraulic System - General
3XL 4100/XL 5100 HYDRAULIC SYTEM OPERATIONS MANUALForm No. 29703

III. Hoses, Tubing and Clamping
Hoses, tubing and the clamping method of each is designed to provide maximum operating life and safety
values of these components. Hoses and tubing should always be protected from vibrating against each other or
sharp edges which could wear a hole in them causing failure and a safety concern. See Figure 1
Hoses: A hose should never be used in a circuit without a minimum safety margin burst pressure of at least 4 to
1to the highest acheivable circuit pressure. Replacement hoses should be stored in a dry atmosphere with a
storage life not to exceed 3 years.
Tubing: Hydraulic tubing should not be used in a circuit without a minimum safety margin burst pressure of at
least 4 to 1 to the highest achievable circuit pressure. Tubing used on the GRADALL is equipped with a circuit test
port. The use of tubing also assists with system heat disapation. Replacement tubing should be stored in a dry
atmosphere and must be free of rust and contaminants.
Clamping: Hose and tubing runs are protected from unwanted movement by clamping. Clamps should be sized
correctly for the hose or tube on which it is used. Multiple hose/tubing clamps are available and their use is
recommended where possible. Do not operate the machine with damaged or broken clamps. The appropriate
Gradall Parts Manual for the machine lists all hose/tubing clamps used and their location is shown on the
parts page.
Replacement hose and tubing should be supplied by your GRADALL distributor. The use of Generic replacement
hose and tubing is not recommended.
Hose fitting torque values are listed in Appendix A. Adherence to these values will greatly eliminate the possibility
of fittings working loose causing fluid leakage.
FIGURE 1
HOSE & TUBING CONTROL VALVE AREA
4
Form No. 29703

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IV. Cylinders
There are seven hydraulic cylinders used on the GRADALL XL 4100 and XL 5100 HYDRAULIC REMOTE CONTROL
MACHINES. There is (1) Boom Cylinder (moves telescope boom in/out), (2) Hoist Cylinders (Pivots boom
up/down), (1) Tool Cylinder (Open & Closes Bucket). (1) Steer Cylinder (moves front wheels right or left), and (2)
Oscillation Lock Cylinders (Stabilizes front of machine when in digging mode.) If cylinder by pass or fluid leakage
is detected, contact GRADALL distributor for analysis and correction. Cylinder bypass is usually detected by
movement of the structure the cylinder is attached to whenever the control valve (Joystick setting) is in Neutral.
Boom Cylinder:
Function: Extends and retracts the telescope boom.
Location: Inside main and telescope boom.
Receives fluid through a hydraulic gland fastened to the rear of the cylinder rod.
The main components shown on Figure 2 are:
Cylinder Barrel
Housing for cylinder rod and piston. Receptacle for hydraulic fluid. Extends and retracts when pressurized.
Cylinder Barrel Ball Joint
Fastens to the telescope boom. Allows for cylinder angular movement as the boom extends and retracts.
Cylinder Rod
Component to which the piston is attached. Fastened to the boom cradle rear plate at the rod bearing retainer.
The hollow rod is equipped with an internal hydraulic tube that carries fluid to the barrel end of the cylinder.
Internal Cylinder Rod
Function is to carry hydraulic fluid to the barrel end of the cylinder. Location is inside of the cylinder rod.
Cylinder Gland
Function to deliver fluid to selected port in the cylinder. Equipped with seals that allow rotation & prevents fluid
leakage. Allows for boom tilt.
Rod Bearing
Location: back of the cradle in boom cylinder retainer. Function: Provide structural attachment of the boom cylinder
rod to the boom. Allows the boom cylinder rod to rotate and flex (during boom movement) without binding.
Locknut
Function: to secure boom cylinder in the boom. Location: at back of boom cylinder retainer plate.
Refer to XL 4000/5000 Upperstructure Mechanical Adjustment & Repair Manual (Form 29604) for
bearing and locknut removal and installation instructions.
Extend is part of a regenerative circuit. Fluid from rod side joins fluid from the pump to fill the barrel side
whenever the telescope boom extends. Equal pressure is then available to both sides of cylinder piston. Larger
barrel area forces boom to move out. See Figure 3 and Figure 65
Retract circuit - Has porting designed into the cylinder rod O.D. Fluid passes through these ports, supplying the
cylinder rod side area inside the barrel, retracting boom. This side of the circuit is not nogenerative.
See Figures 4 and Figure 64
Re-pack kits available.
Refer to XL 4000/5000 Upperstructure Mechanical Adjustment & Repair Manual (Form 29604) for
removal & installation instructions.
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XL 4100/XL 5100 HYDRAULIC SYTEM OPERATIONS MANUALForm No. 29703

IV. Cylinders (continued)
FIGURE 2
BOOM CYLINDER
Locknut
Cylinder Barrel
Cylinder Rod
Internal Tube Ball Joint Cylinder Rod Gland
Bearing
FIGURE 3
BOOM CYLINDER:
REGENERATIVE MODE
Front Machine Rear
Hydraulic Pressure from control valve
(Both sides of piston equal pressure)
Barrel Movement
(Results from area differential - barrel to rod side of piston)
FIGURE 4
BOOM CYLINDER:
STANDARD CYLINDER MODE-RETRACT
Front Machine
Return From Barrel Side
Hydraulic fluid
Rear
Pressure
Fluid
Return
Fluid
Pressurized
Hydraulic Fluid
6
Form No. 29703

Hoist Cylinder
See Figure 5
Function is to raise and lower the boom assembly
Quantity 2
Location-under boom cradle
Fastened to boom cradle and main frame
Standard cylinder hydraulic circuit. Not part of a regenerative circuit.
Standard cylinder, ie. cylinder rod extends & retracts when pressurized
Re-pack kits available
Tool Cylinder
See Figure 5
Function: Open and close bucket on standard machine
Location at end of telescope boom
Fastened to telescope boom at barrel end and bucket adapter at rod end
Standard hydraulic cylinder, ie., cylinder rod extends & retracts when pressurized
Refer to XL 4000/5000 Upperstructure Mechanical Adjustment& Repair Manual (Form 29604) for
removal and installation instructions
Re-pack kits available
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FIGURE 5
HOIST AND TOOL CYLINDER
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IV. Cylinders (continued)
XL 4100/XL 5100 HYDRAULIC SYTEM OPERATIONS MANUAL
Form No. 29703 7

IV. Cylinders (continued)
Steering Cylinder
See Figure 6
Function: Moves front wheels right or left for directional travel
Location: Front right side of carrier
Mounting: Front steer axle and chassis frame
Standard hydraulic cylinder, ie., cylinder rod extends & retracts when pressurized
Adjustable rod end
Re-pack kits available
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FIGURE 6
STEERING CYLINDER
Tie Rod Nut
Cylinder Base
Pin Clip Tie Rod
O-Ring
Piston
Tube Back-up Ring
Piston
Nut
O-Ring
Pipe Plug
Tie Rod Nut
Clevis Pin
Cylinder Head
Tie Rod Nut
Back-up Ring
Clevis
Cap Screw
Pin Clip
Clevis Pin
Clevis Nut
Rod
Wiper
O-Ring
O-Ring
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Form No. 29703

IV. Cylinders (continued)
XL 4100/XL 5100 HYDRAULIC SYTEM OPERATIONS MANUAL
Form No. 29703 9
Oscillation Lock Cylinder
Function: Stabilizes front of machine when in digging mode
Location: Front steer axle and chassis frame
Quantity: 2
Standard hydraulic cylinder, ie., cylinder rod extends and retracts when pressurized
Re-pack kits available
FIGURE 7
OSCILLATION LOCK CYLINDER
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Clamp
Assembly
Clamp
Hex HD
Cap Screw
Cylinder Head &
Tube Assembly
Cylinder
Head Tube
Hex
Lock Nut
Piston Head &
Assembly
Piston Piston Ring
O-ring
Piston Rod
Retaining Ring
Retaining
Ring
Lockwasher
Seal
Ring
Rod
Wiper
O-Ring
Back-up Ring
Gland

V. Reservoir
Reservoir
The hydraulic reservoir is located at the rear of the upperstructure frame, behind the boom. It is a major
component of the hydraulic system incorporating many design features necessary for correct hydraulic
performance. These features are:
Storage Capacity:
The reservoir is correctly sized to provide a sufficient volume of hydraulic fluid to allow all circuits to fully cycle and
still maintain a correct volume of hydraulic fluid to prevent pump cavitation.
Capacity Checks:
Sight gauges and an electrical indicator monitor fluid levels in the reservoir.
See Figure 8 & Figure 9
Heat Dissipation:
The external reservoir surface assists in heat dissipation from hot hydraulic fluid. There is a fluid temperature
indicator located in the reservoir. See Figure 8 & Figure 9 This indicator warns of high fluid temperature at the
moniter in the operators cab.
Turbulence Control:
Internal baffles welded in the reservoir reduces foaming by controlling hydraulic fluid turbulence. This allows
entrapped air to dissapate from the hydraulic fluid.
Accessabillity:
Access covers are designed into the reservoir. These allow entrance into the internal areas to facilitate cleaning of
normal sediment build-up.
Air Breather:
A pressurized breather vents air to the atmosphere once it exceeds 10 PSI. See Figure 10 The reservoir is
pressurized by the machine air system. The reservoir pressure is set of 6-8 PSI. This forces hydraulic fluid into the
pump supply lines. An electrical pressure switch located on the pump suction tube warns of low air pressure at the
monitor in the operators cab.
Drainage:
Fluid drainage plugs in the reservoir bottom are provided for routine maintenance.
Return Filter:
The reservoir houses a 10 micron hydraulic fluid return filter. Hydraulic fluid passes through this filter before it
enters the reservoir. This filter assembly includes a magnet, a 15 PSI. bypass valve, and a removable cover for
ease of service. Bypass condition is indicated via an electrical switch on the dump tube from the control valves.
Suction Screen:
Filtered hydraulic fluid supplied to the pumps leaves the reservoir through the outlet port. Large contaminants are
prevented from entering the pump supply circuit by a 100 mesh suction screen (filter) located inside the reservoir
on the outlet line to the pump.
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Form No. 29703

V. Reservoir (continued)
FIGURE 9
RESERVOIR CAPACITY CHECKS
& ELECTRICAL FLUID INDICATORS
FIGURE 8
RESERVOIR
9 Suction Screen
5 Accessibility
1, 3, 4 Capacity Heat
Dissipation Turbulence
6 Air Breather
(Located in Engine
Compartment)
See Figure 10
8 Return Filter
2 Capacity Check
7 Drain Plug
11 XL 4100/XL 5100 HYDRAULIC SYTEM OPERATIONS MANUALForm No. 29703

VI. Filtration and Cooling Circuit
Filtration
XL 4100 & 5100 SERIES EXCAVATORS use 6 filters to condition and cleanse hydraulic fluid. These filters are
located in the reservoir area and the engine compartment. See Figure 10 for filter locations and Figure 11
for filtration and cooling circuit.
Suction Screen (100 mesh)
Mounted inside reservoir on outlet line to pump. See Figure 8 Prevents foreign objects from entering pump
intakes. When draining reservoir for routine oil changes, remove & inspect this screen. Do not attempt to clean.
Replace if contaminated.
Breather (10 micron)
Mounted in the engine compartment. See Figure 10 Allows air to escape when reservoir pressure is above 10
PSI. Allows air to enter the reservoir when pressure is below 0.3 PSI vacuum. Low air pressure (6 PSI) warning
switch located in dump tube and monitor in operators cab. Replace when low pressure warning light stays on.
Replace filter element whenever other hydraulic system filter elements are replaced.
Recirculation Return Filter (8 micron)
Mounted in engine compartment. See Figure 10 Reconditions hydraulic fluid received from the recirculation
pump whenever the engine is running. Equipped with a 25 PSI relief valve which allows fluid to bypass
whenever this value is exceeded. A mechanical pressure gauge and an electrical switch warns of high filter
pressure. Replace the filter element whenever high pressure warning devices consistantly read high.
Swing Suction Filter (8 micron)
Mounted in engine compartment. See Figure 10 Reconditions hydraulic fluid received from the recirculation filter.
Has No bypass features. Delivers fluid to the intake port of the swing pump. Equipped with a mechanical gauge
and an electrical switch to warn of low filter pressure. Replace filter element anytime the mechanical gauge so
indicates.
Pilot Filter (10 micron)
Mounted inside engine compartment. See Figure 10 Equipped with a pop-up filter condition indicator.
Whenever red color shows, the element must be changed. Will show bypass whenever fluid is under 100°F.
Receives fluid from 6.6 GPM pilot pump. Filters all pilot circuit fluid.
Reservoir Return Filter (10 micron)
Mounted in main return line, inboard side of reservoir. See Figure 8Reconditions hydraulic fluid returning from
main control valve assemplies. No oil is supplied to this filter unless the control valves are activated. Equipped
with a magnet, 15 PSI bypass valve, and an electrical bypass indicator. See Figure 9 Filter element should be
changed if the warning light comes on with fluid temperature @ 100°F. After element change, ensure all seals
are correctly placed whenever cover is reinstalled and tightened.
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Form No. 29703

VI. Filtration and Cooling Circuit (continued)
FIGURE 10
ENGINE COMPARTMENT LEFT SIDE
Reservoir Air Pressure
Regulator
Swing Suction
Filter & Gauge
Recirculation Return
Filter & Gauge
Pop Up Filter Indicator
Pilot Filter
Reservoir Air
Pressure Gauge
Air
Breather
Pilot Pump
Recirculation
Pump
Air Pressure
Drain Thermal
Bypass Valve
Pressure
Reducing Valve
Pilot
Manifold
NOTE!NOTE!
NOTE!NOTE!
NOTE! For location of the filters in the hydraulic system See Figure 11.
13 XL 4100/XL 5100 HYDRAULIC SYTEM OPERATIONS MANUALForm No. 29703

VI. Filtration and Cooling Circuit (continued)
FIGURE 11
FILTRATION/COOLING CIRCUIT
Air
Breather
Diverter Tool Hoist Tilt
Reservoir
Return Filter
Hydraulic
Reservoir
Suction
Filter
Back Pressure
Valve
Travel Boom
Engine
Heat
Exchanger
Oil Cooler
Pilot
Manifold
Priority Flow
Regulator
Recirculation
Pump
Return
Filter
Pilot Filter
Pilot Pump Suction
Filter
Swing
Thermal
Bypass Valve
Center Pin
Remote Steering Valve
4 GPM
Heat Exchanger (Oil Cooler) Circuit
Thermal Bypass Valve
Located in engine compartment. See Figure 10
Also called Heat Exchanger Valve
Receives fluid from Recirculating Pump and Pilot Manifold
Directs fluid to the heat exchanger (oil cooler) if the hydraulic fluid is above 120°F
Equipped with a 70 PSI relief valve protects the heat exchanger (oil cooler)
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Cooling
XL 4100 and XL 5100 Excavators use a cooling system to maintain proper hydraulic fluid temperature. This
allows for optimum machine performance by keeping hydraulic components at peak efficiency and reducing the
possibility of component binding caused by heat. The major components in the cooling system are:
Recirculation Pump, Pilot PUmp, Thermal Bypass Valve and the Heat Exchanger (Oil Cooler).
Hydraulic fluid directed to the heat exchanger is supplied by the Pilot and Recirculating Pumps. The recirculating
pump delivers 14 GPM. A portion of this 14 GPM (not exceed 4 GPM) is directed to the steering and
oscillation lock valves of the undercarriage before returning to the heat exchanger.
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Form No. 29703

VI. Filtration and Cooling Circuit (continued)
Backpressure Valve
Located in main control valve bank return line. See Figure 11
Pressure setting relief 120 PSI
Prevents hydraulic fluid cavitation to control valves
FIGURE 12
HEAT EXCHANGER RADIATOR (OIL COOLER)
Heat Exchanger Radiator
(Oil Cooler)
Engine Radiator
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Heat Exchanger Radiator (Oil Cooler)
Located in front of the engine radiator. See Figure 12
Keep space between heat exchanger and engine clear of debris
Cools hydraulic fluid approximately 100° above ambient temperature
Receives fluid from Thermal Bypass Valve
Maximum flow through heat exchanger is 20.6 GPM
Directs fluid from the heat exchanger to the reservoir filter
Replace if system failure is caused by major contamination. It is very difficult to flush this and be certain it is
free of contaminants.
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15 XL 4100/XL 5100 HYDRAULIC SYTEM OPERATIONS MANUALForm No. 29703

XL Series machines use a bent-axis, variable-displacement main pump to provide fluid to all hydraulic functions
(except swing and pilot). The main pump assembly contains a pump housing, pump end cover, pump splitter
box, two pump assemblies, pump stroking controls and an auxiliary drive PTO for other hydraulic pumps. Both
pump groups are connected to a single set of pump stroking controls that vary pump displacement in response
to system pressure. This works to constantly match hydraulic horsepower to engine horsepower during machine
operation.
The main pump assembly is bolted to the engine flywheel housing. The flexible coupling attached to the flywheel
drives the main pump assembly. A pump input shaft disconnect (clutch) is not provided. Gear sets within the
pump housing provide a splitter box to drive the pump rotary groups and the pump PTO drive. See Figure 13
Supply fluid from the hydraulic reservoir completely fills the main pump case. This fluid lubricates and cools internal
parts. It also works as suction fluid for both rotary groups of the main pump. When the system is exposed
to a vacuum, the hydraulic fluid is changed, or a pump is removed or changed, the pump housing must be
completely filled with clean hydraulic fluid and air purged before startup per instructions on pages 18 & 19.
Each pump group supplies fluid to a valve bank which then supplies fluid to machine hydraulic functions. A
diverter valve in the bucket/hoist/tilt valve bank allows excess pump flow within one valve bank to be made
available to functions within the other valve bank. See Figure 14 Pump stroking controls are connected to port
A2 on the pump and valve load sensing circuit (sending a signal of the highest circuit pressure to the pump).
These stroking controls read the two pressure signals to change pump displacement as needed and to match
pump flow to hydraulic system requirements. When controls are not being used, the pump goes to standby and
maintains enough flow for standby pressure (300 - 350 PSI). See Figure 15
The rotary groups in the main pump swivel from 25° at maximum stroke to 0° at minimum stroke. Swivel angle
depends upon system flow requirements and system pressure. Pump controls affect the swivel angle of the pump.
Main Hydraulic Pump Adjustments. See 16
Pump Operation Adjustment Screws (3)
Located at the top of the pump end cover.
Horsepower Control Adjustment Screw
Located at the top and front of the main pump. Adjusts thepoint at which this control overrides load
sense control. Destrokes the pump to prevent overloading the engine. It is linked to the pump stroke
piston and uses pump angle and pump output pressure to determine operation.
Pump Cutoff Adjustment
Located behind the horsepower control. Reads the load sense pressure from the valves. Cuts off the
loadsense signal if pump output pressure is higher than the control setting. Prevents over-pressure
of the pump.
Load Sense Control
Located on the side of the pump control block. Maintains pressure differential between pump output
pressure and load sense signal. Constantly reads pump output pressure and load sense signal pressure.
Senses control valves as variable orifices and maintains a constant pressure drop across control valves.
Pressure differential is also known as main pump standby pressure. Plus, the maximum stroke control
should always be set to the maximum position (with no adjustment required). It is located at the bottom of
the pump end-cover.
VII. Main Hydraulic Pump
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Form No. 29703

VII. Main Hydraulic Pump (continued)
FIGURE 13
MAIN PUMP ASSEMBLY (TOP CROSS SECTION)
Outlet A1 Port
Pump Case
Gearsets
Barrel Outlet A2 Port
End Cover
Swivel Fork/Stroking Piston Assembly
Inlet Port
Lens
Input Shaft
Piston
17 XL 4100/XL 5100 HYDRAULIC SYTEM OPERATIONS MANUALForm No. 29703

VII. Main Hydraulic Pump (continued)
Before starting the engine, make sure all assemblies are complete with all motor cases and gearbox
cases filled per specification.
Fill reservoir to top sight gauge and charge reservoir to 6 PSI (set regulator to 6-8 PSI).
Bleed air from the following:
Swing motor - loosen hose at case drain port.
Swing brake - loosen special bleed port (on back side).
Swing pump - R port (on top center of pump).
Swing pilot lines - loosen both hoses at the swing pump.
Swing pump - loosen suction hose at pump.
Main pump - remove top case drain plug (on top surface near swing pump).
Thermal bypass valve - loosen both hoses.
All pilot lines on control valve (at actuators).
Remote dig brake (chassis) - loosen hose on valve.
Start the engine at idle speed (800 RPM) for 15 seconds (all valves in Neutral). Stop engine.
Bleed air from the following:
Pilot valve - loosen hose at pilot shut-off valve in the valve module.
Swing motor - slightly loosen working lines on top of motor.
Swing pump - install gauge lines in M5 and M6 test ports to vent.
Restart engine at idle speed.
Check swing charge pressure on front port G of swing charge valve. Pressure should be 320-400 PSI
within 10 seconds. If this does not occur, shut off engine and find the cause of the problem before
restarting.
Check pilot pressure 480-500 PSI.
Lower right-hand armrest to turn on pilot circuit. Then quickly move each pilot control (including foot
pedals) back and forth 3 times to vent remaining air. (do not actuate valves).
With boom level, actuate boom out 2" then in 2". Repeat 3 times. Do not hit boom in end of stroke until
the last stroke.
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Form No. 29703