Genie GTH 6025R Telehandler Service Repair Workshop Manual
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INDEX
Handler with telescopic boom
GTH-6025 R (da matr. 16760)
SERVICE MANUAL
Code 57.4403.2200 - 1
st
Edition 02/2008
English
Edition
Document 57.4403.2200 - 1
st
Edition 02/2008
INDEX
MANUAL CONTENTS
INTRODUCTION
Sect. 1 SAFETY RULES
Sect. 2 TECHNICAL SPECIFICATIONS
Sect. SCHEDULED MAINTENANCE INSPECTIONS
Sect. 4 SCHEDULED MAINTENANCE PROCEDURES
Sect. 5 TROUBLESHOOTING
Sect. 6 SCHEMES
Sect. 7 REPAIR PROCEDURES
GTH-6025 R
GENERAL INDEX
5
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GTH-6025 R
SERIAL NUMBER IDENTIFICATION
6
Machine denomination Literature valid up to serial number
GTH-6025 R 16760
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GTH-6025 R
INTRODUCTION
i
INTRODUCTION
Important
Read, understand and obey the safety rules and
operating instructions in the GTH-6025 R Operator's
Handbook before attempting any maintenance or repair
procedure.
This manual provides the machine owner and user with
detailed information on the scheduled maintenance. It also
provided qualified service technicians with infromation on
troubleshooting and repair procedures.
Basic mechanical, hydraulic and electrical skills are
required to perform most procedures. However, several
procedures require specialized skills, as well as specific
tools and equipment.
In these instances, we strongly recommend letting service
and repair the machine at an authorized TEREXLIFT
service center.
Technical Publications
No part of this publication may be reproduced, stored in a
retrieval system or transmitted in any form or by any means
without prior written permission from TEREXLIFT srl.
In pursuing a policy of constant quality improvement,
TEREXLIFT srl reserves the right to make changes at any srl reserves the right to make changes at any
time and without undertaking to give prior notice; therefore,
also this publication may be subject to modifications� .
Contact Us
http://www.terexlift.com
e-mail: info@terexlift.it
http://www.genielift.com
© Copyright 2008 TEREXLIFT srl - All rights reserved.
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INTRODUCTION
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DESCRIPTION OF THE MACHINE OPERATION
The oil-pressure system of this machine consists of two
macro sections, namely turntable and undercarriage,
corresponding to the machine's main parts. From an oil-
pressure point of view, these two sections are connected
with one another by the 13-way hydraulic rotary joint
(9).
The source of mechanical energy of this machine is a
Cummins turbo-compressed diesel engine (1), model
QSB4.5 with intercooler, which supplies 119 kW at 2300
rev/min and with a max torque of 624 Nm at 1500 rev/
min.
On the flywheel side of the engine, and connected to
this engine by a Technodrive coupler with elastic joint
and with a 1-to-1 ratio, there is a Rexroth closed-
loop pump for hydrostatic drives, model A4VG90 (2)
with electroproportional adjustment valves. The max
displacement of this swashplate pump is 90 cm
3
and the
max calibration pressure is 430 bar. This pump is used
to supply hydraulic power under form of pressure and
flow rate which is then used for moving the machine.
On the through-shaft of such drive pump there is a
Bosch-Rexroth variable displacement piston pump
with swashplate suitable for open lopp circuits, model
A10VO60DFR (3), equipped with flow and pressure
control valve. The displacement of this pump is 60 cm
3
.
The function of this pump is to provide hydraulic power,
under form of pressure and flow rate both to the steering
cylinder of the machine, and to the telescopic boom and
slewing turntable circuits. This "load sensing" pump
is adjusted through an adequate piloting line which
provides the pump a pressure signal corresponding to
the max load of all the users fed by this pump.
Between pump (3) and the electro-proportional main
valve (8), a one-way valve (5) is placed to avoid that oil
at pressure, produced by the power-driven emergency
pump (48), may escape from pump (3) when this is
stopped.
The assembly of the two pumps involves they have
a rotation velocity equal to the speed of the diesel
engine.
A third Casappa fixed displacement gear pump suitable
for open loop circuits (4) with a displacement of 25 cm
3
,
is installed on the PTO of the engine located on the
distribution side. This pump feeds the servo-assisted
braking system (35) and the Casappa fixed displacement
hydraulic motors (20 cm
3
) (6) and (42) which activate
the heat exchanger cooling fans of diesel engine and
hydraulic circuit.
The circuit of pump (4) is protected by a pressure relief
valve (33) calibrated to 160 bar.
The suction lines of the open-loop pumps (3 and 4)
and the power-driven emergency pump (48) are not
protected by filters and are conveyed to a single port
on the hydraulic fluid tank (32). Between this port and
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the suction lines of the aforesaid pumps, there is a gate
valve (31) that allows to perform important maintenance
interventions on the oil-pressure circuit of the machine
without emptying the oil tank. This tank has a capacity
of 230 litres.
On the contrary, the drive pump (2) is protected by a
special filter (45), placed on the discharge line of pumps
(3 and 4). This filter purifies the oil from the open circuits
of the machine (boom-turntable control circuit and
service and parking brake feeding circuit) and allows
to have an additional oil port for the drive suction line
with a minimum pressure of 0.5 bar. This construction
feature of the filter guarantees significant advantages in
terms of absence of cavitation in the drive suction line,
especially when the machine is started from cold. Valve
(46).
The one-way valve (34) set to 2.5 bar protects the
pump housing against high pressures and guarantees
a certain circulation of the drain oil to the hydrostatic
motor reducing, in this way, the temperature.
From port “G” of the drive pump (2) low-pressure oil
is taken (25-30 bar). This oil is first conveyed to the
undercarriage through port 11 of the hydraulic rotary joint
(9), and then used for the two-speed shift-on-fly gearbox
circuit (51) and for the differential anti-slip circuit through
the solenoid valve (77) which activates the mechanism
placed inside the front axle (57). Through the same low-
pressure line the Pr port of the electro-proportional main
valve (8) is fed.
The hydraulic energy produced by the drive pump (2)
and conveyed to the undercarriage through ports n.1
and n.2 of the hydraulic rotary joint (9), is converted into
mechanical power by the Rexroth motor for hydrostatic
transmissions, model A6VM107 (50) equipped with an
electroproportional adjustment valve and with a flush
valve (73) for reducing the max temperatures inside the
drive circuit.
Through port n. 12 of the hydraulic rotary joint, the flow
coming from the drain circuit of the transmission pump
(2) reaches the motor (50) and, through port n.7, this
motor conveys all the drain flow to the hydraulic oil tank
(9). This allows to keep the internal temperature of the
circuit within acceptable operational limits.
The electroproportional valves of pump (2) and motor
(50) are controlled by a dedicated electronic control
unit (Linde) which is connected to the remaining control
devices of the machine through the digital network.
The motor is flanged to a two-speed shift-on-fly gearbox,
model 357 (51). Speeds are engaged by a special oil-
dynamic cylinder (52) located inside the gearbox, while
the selection of the first and second speed is controlled
by a 4-way/2-position solenoid valve (53) of the on/off
type with mechanical safety lock.
The mechanical torque at the gearbox output is
transmitted to the front axle (57) and the rear axle (58),
both model 213 manufactured by Dana, through two
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Cardan shafts.
The double-displacement hydraulic drive (7) of “load
sensing” type (max./min. displacement of 220/60 cm
3
)
receives oil from the priority valve built in the inlet head
of main valve (8) in relation to the “load sensing” signal
sent by the hydraulic drive and connected to such main
valve with function of pilot signal. In this way, the input
flow to the hydraulic drive will be exactly the one needed
for the instantaneous steering functions; any excess
flow of the pump will be made available for the functions
of the telescopic boom and other auxiliary functions, if
needed.
The steering circuit is protected against input
overpressures by a pressure reducing valve (47) set to
180 bar. On the two delivery lines, there are other two
reducing valves with anti-shock function set to 220 bar.
The scope of these two valves is limiting possible shocks
on the steering wheel due to overstress on the steering
cylinders. The three pressure reducing valves are installed
in the hydraulic drive (7). This model of hydraulic drive
can self-adjusts the minimum displacement (60 cm
3
) and,
as a result, reduce the effort for the emergency steering
in case of a too low feeding pressure (failure).
The steering circuit is completed by the front steering
cylinder (55), the rear steering cylinder (56) (these
cylinders being integral part of the front axle (57) and
the rear axle (58) respectively) and by a 4-way/3-position
solenoid valve (54) for the selection of the three different
steer modes: rear wheels straight, co-ordinate front/
rear steering (four-wheel steer), independent front/rear
steering (crab steer). When the solenoid valve (54) is
not energised, the front steering cylinder is fed by the
hydraulic drive and the rear cylinder is blocked. When
one magnet or the other of the solenoid valve (54) is
energised, the chambers of the cylinders are connected
in a different manner thus causing the desired effect on
the steering mode. The connection of the steering circuit
between the section integral of the turntable and the one
integral of the undercarriage is done through ports n.8
and n. 9 of the hydraulic rotary joint (9).
The Rexroth electro-proportional distributor (8), with
5 modular sections, receives oil from pump (63) and
feeds all the movements of the telescopic boom and
the turntable, and provides an oil flow to the auxiliary
lines for the secondary functions such as turntable lock,
outriggers and frame levelling.
This main valve consists of an input head with 3-way
pressure compensator used as a flow regulator for the
user which works at max load (load sensing), and as
a discharge valve when the pump flow is not used for
the boom movements, and of 5 modules. Four of these
modules control specific functions of the telescopic
boom (lifting/lowering, attachment holding frame rotation,
extension/retraction, attachment lock/unlock) and the
fifth module controls the rotation of the turntable of the
machine.
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In the head there is a pressure relief valve set to 270
bar which, acting on the line of the “load sensing” signal,
limits the maximum pressure at the inlet of the main
valve through the compensator.
On the main inlet head of the main valve, there is
also a safety solenoid valve which, when de-excited,
discharges the input pilot pressure, thus preventing the
main valve from working. This solenoid valve is used as
a “dead man” control and is activated by the relevant
button on the joysticks in the driving cab. The pilot head
delivers oil at pressure to the 5 pilot modules of the main
valve. These modules operate the relevant main sliders
in relation to the command signal they receive from the
joysticks via the control unit.
Module 1 of the main valve controls the telescopic boom
lifting cylinder (12). This cylinder has one single-acting
compensation valve (13) with safety function. The control
module of element 2 of the main valve is the electro-
proportional type with electrical feed-back and integrated
electronics. The 0,5-lt. accumulator prefilled at 35 bar
(14) and located on the line of the differential chamber
of the lifting cylinder (12), allows for damping the boom
swings when the same boom is moved down.
Module 2 of the main valve controls the boom telescopes
extension cylinder (15). This cylinder is equipped with
a double-acting compensation valve (16) with safety
function. The control module of this element of the main
valve is the electro-proportional type with electrical feed-
back and integrated electronics.
Module 3 of the main valve controls the fork joint cylinder
(17) of the telescopic boom. This cylinder is equipped
with a double-acting compensation valve (18) with safety
function. Paralleled to this cylinder we find the fork levelling
cylinder (19) (or balancing cylinder) equipped with a
special double-acting compensation valve (20). Inside
this valve, the one-way valves are installed in a reverse
manner with respect to the normal position to avoid the
pressurisation of the cylinder when the rotation command
of the attachment holding plate is operated. Again inside
this valve, there are other two one-way valves set to 5
bar with anti-cavitation function (21). These valves are
used to prevent the oil from escaping the closed circuit
created when the operator moves the boom up and
down between the fork tilting cylinder and the levelling
cylinder (as the fork horizontality is guaranteed by the
tightness of these cylinders), and to deliver hydraulic
oil when there is a pressure drop inside the cylinder.
Feeding is guaranteed by the pressure reducing valve
(11). The control module of element 3 of the main valve
is the electro-proportional type with electrical feed-back
and integrated electronics.
On the two control lines of the cylinder (17), and integral
to module 3, there are two pressure relief valves (84) set
to 295 bar which protect the automatic levelling system
of the forks when the boom is moved up and down and
in case of overload on the attachment holding plate (ex.
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use of the bucket).
Module 4 of the main valve controls the attachment
locking cylinder (23). This cylinder has a double one-
way valve with hydraulic release, acting as safety valve
(24). The pilot module of element n. 4 of the main valve
is the electroproportional type with integrated electric
and electronic feedback.
On one of the two hydraulic control lines of this section
of the main valve, there is a 3-way/2-position electric
divider with on/off control (22). When this divider is not
energised, the oil at pressure coming from the module of
the main valve, is sent to the attachment locking cylinder.
On the contrary, when the divider (22) is energised, the
oil at pressure from element n.4 of the main valve (8),
is made available for the auxiliary feeding line of the
turntable lock/unlock function through a cylinder (28)
equipped with a double one-way valve with hydraulic
release used as safety valve. The cylinder is operated
by solenoid valve (30). Afterwards, through port n. 3 of
the hydraulic rotary joint (9), oil is used for the operation
of the outriggers and the frame levelling.
On the two feeding lines and close to the terminal part
of the end trunk, there are two quick-fit connectors (25)
for the connection of the hydraulic lines of any optional
equipment needing a hydraulic power for their operation
(e.g. hydraulic winch and jib, mixing bucket, etc.).
Module n. 5 of the main valve controls the hydraulic
slewing motor of the turntable (26), equipped with brake
with internal mechanical block and external hydraulic
release. The mechanical torque produced by this motor
is transmitted to the turntable through an epicyclic
reduction gear with two stages and a slewring with
internal toothing.
The feeding line of this motor is equipped with a double-
acting compensation valve (27), used also as safety and
anti-cavitation valve. The pilot module of this element
of the main valve is of electroproportional type with
integrated electric and electronic feedback.
The main valve (8) is equipped with a pilot line of the
“load sensing” type which, at its turn, receives an analog
pressure signal from the hydraulic drive (7). The signal
is then sent to the "load sensing" port of pump (3), thus
guaranteeing the adaptation of the pump adjustment to
the maximum load on the various users served by this
pump under any conditions.
The pressure relief valve (11) calibrated to 30 bar is
placed upstream of the pressure inlet port of the main
valve (8). This valve is used to deliver low-pressure oil
(30 bar) to the anti-cavitation circuits of automatic fork
levelling system.
The block cylinder of the slewing turntable (28) is
equipped with a double one-way valve (29) with hydraulic
release, acting as safety valve, and is controlled by
the 4-way/3-position solenoid valve of the on/off type
(30). As already mentioned, the turntable lock/unlock
is possible through the simultaneous energisation of
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module n.4 of the main valve (8), the electric divider
(22) and the solenoid valve (30).
The SAFIM S6 servo-assisted braking system with
pedal (35) receives oil from the pump (4) and uses
this oil to pressurise 3 hydraulic accumulators (36 and
37) connected to the same system. The oil at pressure
contained in these accumulator is then used to operate
the service brakes of the two axles (57 and 58) and to
release the parking brake located inside the rear axle
(58).
The fill valve inside the braking system takes the flow
from the feeding line so the pressure on the line of the
accumulators reaches the calibration value of the cutout
valve set to 150 bar. When this pressure is reached, the
valve gradually releases all the flow to line B for other
uses.
The brake pedal located in the driving cab, which is an
integral part of the braking system S6, is connected to
two proportional sliders which control the two separated
lines of the service brake, one for each axle. Such
lines connect the part of circuit in the turntable with the
one in the undercarriage through ports n. 5 and n. 6
of the hydraulic rotary joint (9). In relation to the stroke
of these sliders, a gradual communication between
the feeding line, connected to two accumulators (36)
which, at their turn, are connected to ports R1 and R2
(the accumulators have 0.5-lt. capacity and 50 bar fill
pressure), and the service brake lines is established so
the flow is distributed to such lines and the discharge
line increasing, in this way, the pressure (and as a result
the braking force) on the lines of the service brakes.
When the sliders are in the rest position, the lines of the
service brakes are connected to the discharge.
The pressure switch (38) set to 2-10 bar, paralleled to on
of the two lines of the service brake, sends an electrical
signal when this brake is engaged.
The pressure switch (39) set to 70 bar and connected
to port F, sends an electrical warning signal when the
pressure inside the feeding circuit of the brake lines is
too low to guarantee the minimum braking efficiency.
The accumulator (37) with 2.5-lt. capacity and 55 bar
fill pressure is connected to port R of system S6 and is
used to unlock the parking brake of the rear axle (58).
The connection of the part of this circuit placed in the
turntable to the one of the undercarriage is done through
port n. 13 of the hydraulic rotary joint (9).
The command of the parking brake is controlled by
a special valve with lever control (40) located in the
driving cab. In relation to the position of the lever, the
release line of the parking brake is connected to the
pressure line (parking brake unlocked) or the discharge
line (parking brake locked).
The two pressure switches (41) set to 10-20 bar send
an electrical warning signal when the parking brake is
activated (brake locked).
The oil which is not used by the SAFIM S6 servo-assisted
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The Genie GTH 6025R Telehandler Service Repair Manual is a comprehensive resource for both professional mechanics and DIY enthusiasts. It contains easy-to-read text sections, high-quality diagrams, and clear instructions, making it an invaluable tool for anyone working on the Genie GTH 6025R Telehandler.
This manual covers a wide range of essential information, including safety rules, technical specifications, scheduled maintenance inspections and procedures, troubleshooting, schemes, and repair procedures.
File Format: PDF
Compatibility: All Versions of Windows & Mac
Language: English
Requirements: Adobe Reader
With this manual, you can save time and money by performing repairs and maintenance tasks yourself, with the confidence that comes from having access to the detailed guidance provided. It's an essential resource for getting the job done right and understanding your Genie GTH 6025R Telehandler inside out. Plus, all pages are printable for easy reference.
