5-6193034 Hydraulik SL GB [PDF]

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5 Hydraulic system Technical manual Publ. no. 6193.034 1211, Version 02

CONTENTS HYDRAULIC SYSTEM - DESCRIPTION ...................................................... 5-3 General description - load sensing system ........................................................... 5-3 Function - Load-sensing system .......................................................................... 5-4 Hydraulic component placement, fork lift truck SMV 10-16 B. ......................... 5-6 COMPONENTS - DESCRIPTION ................................................................. 5-8 Variable piston pump, Parker series P2 ............................................................... 5-8 Variable piston pump - Function ........................................................................ 5-9 Load-sensing system ................................................................................... 5-10 Steering priority valve ....................................................................................... 5-13 hydraulic system steering, principle .................................................................. 5-14 Directional control valve, Parker L90LS ........................................................... 5-16 Directional control valve, Parker HV08 ............................................................ 5-18 Accumulator charging block, M0382 ............................................................... 5-20 Hydraulic system fork lift truck SMV 10-16 B, principle ................................. 5-22 Description of the hydraulic system, fork lift truck ........................................... 5-23 MEASUREMENTS AND ADJUSTMENTS .................................................. 5-24 Measuring and setting the hydraulic pressure .................................................... 5-24 Measuring and setting the standby pressure, one pump .................................... 5-24 Measuring and setting standby pressure, multiple pumps ................................. 5-24 Measuring and setting the maximum working pressure .................................... 5-25 Measuring and setting the delta pressure, Delta-P ............................................. 5-26 Measuring and setting the delta pressure, one pump .................................. 5-26 Measuring and setting the delta pressure, two or three pumps ................... 5-26 Pressure discharge in the accumulator ............................................................... 5-28 Measuring and setting the accumulator pressure ............................................... 5-28 Measuring and setting the brake pressure switch ............................................... 5-28 Measuring the accumulator pre charged pressure .............................................. 5-29 Measuring and setting parking brake pressure ................................................... 5-29 Measuring the steering pressure ........................................................................ 5-30 Steering priority valve, adjustment (older models only) .............................. 5-30 Steering priority valve, adjustment (new models only ................................ 5-31 Setting the restrictor and non-return valve ........................................................ 5-32 Parking brake ............................................................................................. 5-32 Measurement and adjustment of head pressure (ECB) ...................................... 5-33 Measurement and adjustment of head pressure (Gantry) .................................. 5-34 FAULT TRACING ......................................................................................... 5-35

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Technical manual Publ. no. 6193.034 1211, Version 02

Hydraulic system - Description HYDRAULIC SYSTEM - DESCRIPTION GENERAL DESCRIPTION - LOAD SENSING SYSTEM In a load sensing hydraulic system the pump only supplies the flow required for the functions on each occasion they are connected, i.e. the pump’s output is not greater than the current load. The hydraulic system in all SMV’s trucks is load sensing. The advantages of a load-sensing system are: • lower energy consumption. • less heat development. • greater precision and more flexible manoeuvring of the machine. • smaller losses and less wear to the hydraulic system. • no flow in the system when it is not used. • only the necessary flow when lifting or moving. • no unnecessary overpressure when lifting small loads.

In a load-sensing system, the load the system is subjected to is measured and this controls the output from the hydraulic pump; the system remains in balance: light load - low output, heavy load high output.

The heart of the system is the variable piston pump. When the load on the system changes, for example, when lifting, a signal provides the pump with information about the change and a corresponding change is made to the output.

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Hydraulic system - Description The diagram shows the principle of a load-sensing system. The load signal (LS) which controls the pump, is taken from the directional control valve.

FUNCTION - LOAD-SENSING SYSTEM The truck driver controls the hydraulic functions using joysticks that actuate the directional control valve. The system is proportional, i.e. a small joystick movement gives a small deflection on the directional control valve (little oil flow), and large joystick movement gives a larger deflection on the valve (large oil flow).

V0015

V0016

A

LS

P

T

When the directional control valve is closed the pump gives a low basic pressure, which is known as standby pressure. When the system is put to work, oil flows through the directional control valve, from P to A, and a pressure drop arises. This is called DeltaP. The standby pressure should be slightly higher than DeltaP. It is important that the pump provides the correct standby pressure in order for the system to work correctly. When the joystick is in the neutral position, i.e. when no work is being carried out, the load signal is 0. The output from the pump, which corresponds to the standby pressure, is very low and with that the output requirement from the diesel engine is also low.

V0017

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Hydraulic system - Description

45

Small joystick movement only requires a small flow, yet high pressure. The load signal provides the pump with information, this is then set to give the right output.

V0018

Both a large flow and high pressures are required in response to large joystick movement. The load signal provides the pump with information, this is then set to give maximum output. 45

V0019

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Hydraulic system - Description HYDRAULIC COMPONENT PLACEMENT, FORK LIFT TRUCK SMV 10-16 B.

V0036

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Hydraulic system - Description 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14.

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Steering cylinder Variable piston pump, 105 cc Gear pump, 23 cc Accumulator Steering orbitrol Tilt cylinder Lifting cylinder Side shift cylinder Directional control valve Multi-disc brake Parking brake Steering priority valve Accumulator charging block Hydraulic tank

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Components - description COMPONENTS - DESCRIPTION VARIABLE PISTON PUMP, PARKER SERIES P2

V0007

V0006

1. 2. 3. 4. 5. 6.

Input shaft Adjuster screw, Delta P Adjuster screw, Pmax Adjuster screw, displacement Outlet Inlet

7. 8. 9. 10. 11.

Servo piston Swashplate Pump housing Piston Barrel

V0008

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Components - description VARIABLE PISTON PUMP - FUNCTION The input shaft rotates and drives the barrel and pistons. Oil is drawn into the cylinders on the inlet side and is pressed out of the cylinders on the outlet side. The volumes (V1) and (V2) are determined by the angle of the swashplate (A) and the difference between (V1) and (V2) is the volume of oil (displacement) the pump gives per revolution. When the load signal is zero or at full output from the pump, the swashplate (A) is tilted to maximum. The difference in volume on the inlet side (V1) and outlet side (V2) is at its most and the pump supplies maximum oil flow.

V0024

When less oil is required, the angle (A) of the swashplate is reduced. The difference between (V1) and (V2) drops and the pump supplies a smaller quantity of oil.

V0025

With minimal oil requirement, the angle (A) of the swash-plate is virtually 0 and the difference (V1-V2) is at its least and the pump supplies a small oil flow.

V0026

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Components - description Load-sensing system The diagram shows the system with the diesel engine switched off where the pressure and flow are 0. When there is no pressure in the system the pump’s spring-loaded actuator piston (1) is in the position for maximum pump output. The line from the control piston runs via the valve for maximum pressure (Pmax) and standby pressure valve (DeltaP) directly to the hydraulic tank. It is possible to adjust the pressure in both valves with the help of adjuster screws. When the diesel engine is started, the pump gives maximum output for a short period until the standby pressure is reached.

Once the standby pressure has been reached, the valve (2) adjusts the pump and maintains this at the set pressure irrespective of the speed of the diesel engine.

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Components - description When the system is put to work (via the joystick) the directional control valve (3) changes position and the LS line is pressurised. The valve (4) is reset and the pressure in the actuator piston (5) drops. The pump output then increases until it corresponds with the load on the system.

When the pump output corresponds to the load on the system, the valve (6) is adjusted and maintains the pump at the right output.

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Components - description When the cylinder is moved to the end position, the pressure can reach max. pressure. The pressure in the load signal (LS) increases and the valve (4) is reset. The pressure in the actuator piston (5) decreases and the pump output increases.

When the pump output is equal to the set max. pressure for the valve (7) its position changes. The pressure in the actuator piston (8) increases and the pump output decreases. The pressure is maintained until the cylinder moves or the directional valve is switched.

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Components - description STEERING PRIORITY VALVE The steering priority valve is preset to give a controlled pressure of 180-200 bar.

1. 2. 3. 4. 5. 6.

Pressure regulator Load sensor (LS), load signal from steering orbitrol Excess flow (EF), to directional valve Controlled flow (CF), to steering orbitrol External pilot signal (PP) From the piston pump (P)

1. Pressure regulator

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Components - description HYDRAULIC SYSTEM STEERING, PRINCIPLE 1. 2. 3. 4. 5. 6. 7. 8.

Steering cylinder Steering orbitrol Steering priority valve Pressure regulator Shuttle valve Restrictor and non-return valve Variable piston pump, 105 cc Hydraulic tank

V0508

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Components - description Oil is led from the variable piston pump (7) (105 cc) to the steering priority valve (3). The task of the steering priority valve is to always supply the steering system with oil ahead of the truck’s other hydraulic functions. When the diesel engine is started the pressure builds up to the standby pressure. P on the steering priority valve receives standby pressure from the pump. The standby pressure is transferred to CF (controlled flow) and further to the steering orbitrol. Return pressure at the steering orbitrol is fed to PP (Pilot Pressure) on the priority valve. The valve switches position so that the stanby pressure is on EF (Extra Flow) to which the directional valve is connected. A small. contracted oil flow is fed through the LS-line via the steering orbitrol into the tank. When the steering orbitrol is activated (when steering) the pressure on (PP) drops and the priority valve switches position again and oil flows from the pump via the priority valve (P to CF), the steering orbitrol (P) to the steering cylinder. The adjustable pressure regulator (4) opens at maximum steering pressure (steering to end position).

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Components - description DIRECTIONAL CONTROL VALVE, PARKER L90LS

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Components - description 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. 16. 17. 18. 19. 20.

PS, pilot circuit for joysticks TPB, tank connection for pilot circuit B, hydraulic function A, hydraulic function Connections from control joysticks Control for emergency lowering (fork-lift trucks) P1, pump connection T1, tank connection Electrically controlled proportional valve LS, load signal connection, copied PX, pump pressure PL, non-copied load signal Valve for maximum pressure Copy slide; Copies the load signal from hydraulic function to the pump Pressure limiter on load signal; Used for extra functions, for example, joystick steering Pressure regulator for pilot pressure Shuttle: Gives priority to highest load signal Compensator valve: Limits the highest permitted pressure for the circuit Non-return valve Manoeuvre slide

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Components - description DIRECTIONAL CONTROL VALVE, PARKER HV08

6

3 10

A

B

1

10 A B

5-18

9

8

7

6

2

3

5

4

2 spool sections 1 spool section

Hydraulic system

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Components - description 1. 2. 3. 4. 5. 6. 7. 8. 9. 10.

Pressure balance point A-B port P1, pump connection section slide T2, tank connection LSU, load signal connection Load signal, drainage Section slide Plug copy slide Copy slide Non-return valve P, pump connection

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Components - description ACCUMULATOR CHARGING BLOCK, M0382

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Components - description 1. 2. 3. 4. 5. 6. 7. 8.

Solenoid, parking brake Pressure regulator, adjustable, parking brake Manual valve for pressure discharge in the accumulator Pressure limiting valve Non-return valve Restrictor valve Charge valve Pressure regulator, adjustable, accumulator

The accumulator charging block receives oil from a gear pump. Oil is distributed in the block to the accumulator, service brake and parking brake. In the event of engine failure these functions receive oil from the accumulator via the accumulator block. The following components/functions are housed in the accumulator block: • Solenoid (1) for parking brake. Electrically controlled valve to activate the parking brake. When the valve is not activated, the parking brake is employed. • Adjustable pressure regulator (2) for the parking brake circuit. Reduces the pressure from the accumulator to the parking brake circuit. • Valve (3) for pressure discharge. The accumulator is drained manually using a hex key. Used BEFORE working on the hydraulic system. • Valve (4) for maximum pressure preset to 250 bar. Prevents excess charging of the accumulator. • Non-return (5) resp. restrictor valve (6) in the circuit between the pump and the accumulator/service brake. The non-return valve prevents the accumulator from being discharged when the engine is switched off. • Charge valve (7). Regulates the pressure to the accumulator circuit. Controlled by the pressure regulator (8). • Adjustable pressure regulator (8) for the accumulator. Measures the pressure in the accumulator circuit and controls the valve (7). Accumulator charging starts when the pressure is 20 % below the set pressure.

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Components - description HYDRAULIC SYSTEM FORK LIFT TRUCK SMV 10-16 B, PRINCIPLE

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Components - description 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. 16. 17.

Hydraulic tank Gear pump, 23 cc Variable piston pump, 105 cc Restrictor and non-return valve Shuttle valve Steering priority valve Steering cylinder Steering orbitrol Parking brake Multi-disc brake Service brake valve Accumulator Accumulator charging block Return filter Hydraulic functions Directional control valve, L90 Control joysticks

DESCRIPTION OF THE HYDRAULIC SYSTEM, FORK LIFT TRUCK A gear pump (2) (23 cc) supplies the accumulator charging block (13) with oil from the hydraulic tank (1). The pressure is distributed in the block to the accumulator (12), service brake (11) and the parking brake (9). Oil from the block also cools the multidisc brake (10) in the drive axle. The gear pump is seated in tandem on the variable piston pump (3) (Parker series P2, 105 cc). Oil from the piston pump goes to the steering priority valve (6) which distributes the oil to the steering orbitrol (8) and the directional control valve (16) (Parker L90). The priority valve ensures that the steering is given priority over the truck’s other functions. The load signal is led back from the steering orbitrol to the priority valve and to the shuttle valve (5) where it is compared to the load signal from the directional control valve. After the shuttle valve, the load signal is led via a restrictor and non-return valve (4) to the piston pump. The directional control valve is controlled from the control joysticks in the cab and distributes oil out to respective hydraulic functions (15). The return oil from the functions runs via the directional control valve back to the hydraulic tank where the return filter (14) is located. A detailed description of the hydraulic components can be found in the section “Components - description” on page 8.

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Measurements and adjustments MEASUREMENTS AND ADJUSTMENTS MEASURING AND SETTING THE HYDRAULIC PRESSURE Placement of the metering outlet and adjustment points differ slightly on the different truck models. Illustrations show the principle for respective measuring/setting. The pressure values not stated in this publication can be found on the machine card under group 70 “hydr.pressure”. MEASURING AND SETTING THE STANDBY PRESSURE, ONE PUMP The correct standby pressure is a prerequisite in order for the hydraulic functions to work properly. The pressure is measured when the hydraulic system is not working (load signal is zero) and with the diesel engine idling. Check the load signal (LS) 1. Connect a manometer (300 bar) to test point (2). 2. Start the diesel engine and let it idle. 3. Check that the pump load signal is 0 bar. (Hydraulics not used.) 4. If the load signal is not 0, troubleshooting must be carried out. See chapter “Fault tracing” on page 35. NB! If the load signal is not 0, the standby pressure cannot be adjusted to the correct level. Adjust the standby pressure. 1. Connect a manometer (300 bar) to the test point (1) at the pump outlet. 2. Start the diesel engine and let it idle. The pressure should now rise to 33 bar. 3. If necessary, adjust the standby pressure using set screw (3) on the pump marked "Delta P". MEASURING AND SETTING STANDBY PRESSURE, MULTIPLE PUMPS 1. Check that the load signal (LS) is 0 bar as described in “Measuring and setting the standby pressure, one pump”. NB Always start with the pump that is to have the lowest standby pressure and then adjust the other pumps in ascending order of pressure.

1

V0342

1 2

5-24

2

Adjusting screw, stand-by pressure (Delta P) Adjusting screw, max pressure (P max)

2. Connect a manometer (300 bar) to the test point for outgoing pressure from the pumps. 3. Adjust the pressure using the upper set screw marked "Delta P" (1) on the pump. Unscrew the set screw on all pumps to approximately 15 bar. 4. Measure the pressure on the relevant pump. Set the pressure as per the data on the machine card using the set screw (1) on each pump.

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Measurements and adjustments MEASURING AND SETTING THE MAXIMUM WORKING PRESSURE When a hydraulic function is used the working pressure rises to the level required to carry out the work. Maximum pressure is only reached at maximum work load or when a hydraulic function reaches its end position. 1. Connect a pressure gauge (300 bar) to the metering outlet (1). Lift the mast to maximum height in order to achieve maximum operating pressure. NOTE In order to adjust the pressure of a single pump the pressure of the other pumps must set down. NOTE It is important that the maximum operating pressure of the pumps is adjusted in increasing pressure order. 2. Set down the pressure of all pumps by screwing off adjusting screw P max (2) about 2 rev. 3. The maximum pressure is set by means of the lower adjusting screw (P max) on the pumps. 4. At first set the pressure10 bar above the maximum pressure to be set in order to check that the pump is operating properly. Thereafter set down the pressure according to the machine card.

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Measurements and adjustments MEASURING AND SETTING THE DELTA PRESSURE, DELTA-P A pressure drop occurs (DeltaP) when oil flows through the directional control valve. If DeltaP is too low, the pump will not provide sufficient oil flow resulting in the hydraulic system not working correctly. A symptom of a too low DeltaP is that the hydraulic system normally works with a low speed on the diesel engine while at a high speed the system will work slowly or not at all. A too high DeltaP results in the hydraulic functions being difficult to control and that the other advantages of the loadsensing system dwindle. NOTE! The measuring and setting procedure differs for trucks equipped with one variable pump or several variable pumps.

Measuring and setting the delta pressure, one pump 1. Connect a digital pressure gauge to the metering outlet (1) on the outlet on the pump and to the metering outlet (2) on the LS-line. 2. Start the diesel engine and run at 1000-1500 rpm. 3. Run a hydraulic function without a load (not to the end position) with the joystick moved halfway. Read the pressure difference when the function is moving. The difference is DeltaP. 4. If necessary, adjust the delta pressure with the help of the adjuster screw (3) marked “Delta P” on the pump.

Measuring and setting the delta pressure, two or three pumps When measuring the delta pressure on one of the variable pumps, the LS-lines to the other variable pumps must be disconnected and plugged. The LS-outlet on the pumps must be drained to the tank through extra hydraulic hoses being connected to the LS-outlet and routed to the hydraulic tank. Below follows the procedure for one pump. The equivalent is done to measure the other pumps. 1. Connect one of connections on a digital pressure gauge to the metering outlet (1) on the LS-line. 2. Remove the LS-lines on the other pumps and plug the lines (2). 3. Connect extra hoses to the LS-outlets (3).

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Measurements and adjustments 4. Remove the breathing filters and position the hoses in the hydraulic tank (4).

5. Connect the other connection from the pressure gauge to the metering outlet (5) on the pump to be measured. 6. Start the diesel engine and run at 1000-1500 rpm. 7. Run a hydraulic function without a load (not to the end position) with the joystick moved halfway. Read the pressure difference when the function is moving. The difference is DeltaP.

8. If necessary, adjust the delta pressure with the help of the adjuster screw (6) marked “Delta P” on the pump in question. Repeat the procedure to measure the delta pressure on the other pumps.

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Measurements and adjustments PRESSURE DISCHARGE IN THE ACCUMULATOR The accumulator normally holds a high pressure. The pressure in the accumulator must be discharged before working on the truck’s hydraulic systems. 1. Loosen the lock nut using a ring spanner and loosen the Allenscrew in order to relief pressure.

MEASURING AND SETTING THE ACCUMULATOR PRESSURE 1. Connect a pressure gauge (300 bar) to the metering outlet (1) marked ACCM on the accumulator block. 2. Start the diesel engine and let it idle. 3. Press the service brake repeatedly. The pressure drops and you can hear the diesel engine start to work and the accumulator’s charging cycle starts. 4. When the load on the diesel engine decreases, the accumulator’s charging cycle has ended and the pressure can be read. 5. If necessary adjust the accumulator pressure setting on the adjuster screw (2). Turn clockwise to increase the pressure and turn anticlockwise to lower the pressure. 6. Repeat the procedure from point 3 until the right pressure is reached. 7. Open and close the drain cock (3) and check the pressure again.

MEASURING AND SETTING THE BRAKE PRESSURE SWITCH 1. Connect a pressure gauge (300 bar) to the metering outlet (1) marked ACCM, see "Measuring and setting the accumulator pressure". 2. Stop the engine. Switch on the ignition and press the service brake a few times so that the pressure load decreases. 3. The warning symbol shall be lit at 120 bar. 4. When necessary, lift the cover of the pressure switch (4) and adjust the pressure with a screw driver.

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Measurements and adjustments MEASURING THE ACCUMULATOR PRE CHARGED PRESSURE 1. Connect a pressure gauge (300 bar) to the metering outlet ACCM (1). 2. Stop the engine. 3. Press the service brake repeatedly untill the presure decresases. 4. When the pressure reaches 100 bar it should drop immediately to 0 bar. This indicates that the accumulator pre pressure is 100 bar. NOTE If the pressure goes below 95 bar before it drops to 0 bar, it indicates that the accumulator pre pressure is too low. The accumulator is pre charged with 100bar.The pre charged pressure can vary depending on the surrounding temperature.

MEASURING AND SETTING PARKING BRAKE PRESSURE 1. Check the accumulator pressure as set out above. 2. Connect a pressure gauge (300 bar) to the metering outlet (5) marked PRM on the accumulator block. 3. Start the diesel engine and let it idle. 4. Read the pressure. Check that the pressure is 110 bar. 5. If necessary adjust the parking brake pressure setting on the adjuster screw (6). Turn clockwise to increase the pressure and turn anticlockwise to lower the pressure.

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Measurements and adjustments MEASURING THE STEERING PRESSURE 1. Connect a manometer (300 bar) to the test point (1) on the load signal wire on the control pump. 2. Start the diesel engine. 3. Steer to the end position and hold. 4. Read the pressure, 180-200 bar.

Steering priority valve, adjustment (older models only) 5. If necessary, adjust the pressure by removing the hose (2) and turning the adjuster screw inside the valve with a hex key (3) (7/32"). Applies older models only.

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Measurements and adjustments Steering priority valve, adjustment (new models only 1. Loosen the hydraulic hose that is connected to the pressure regulator. 2. Screw out the pressure regulator (4).

4

Pressure regulator 3. Using a screwdriver, turn the adjuster screw (5) on the pressure regulator (4). 4. One half turn corresponds to a pressure change of about 40 bar. - Turn clockwise to increase the pressure. - Turn counterclockwise to decrease the pressure. 5. Tighten the pressure regulator (4). 6. Connect the hydraulic hose to the pressure regulator. 7. Check and measure the pressure, see “Measuring the steering pressure” on page 30.

4 5

Pressure regulator Adjuster screw

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Measurements and adjustments SETTING THE RESTRICTOR AND NON-RETURN VALVE 1. The restrictor and non-return valve (1), mounted on the load signal line, shall be slightly tightened and locked with the Allen-screw. 2. Check that the restrictor and non-return valve (1) is correctly tightened as follows. - Connect a pressure gauge (300 bar) to the load signal line on the 105 cc-pump (also see “Measuring the steering pressure”) and turn the steering wheel to its end position. - The pressure increases to 180-200 bar. - Let go of the steering wheel and note the pressure drop. Correctly adjusted, the pressure should be gone within 5-10 sec. - If the pressure drops faster, the restrictor and non return valve is not tightened enough. - If the pressure is dropping slowly the valve is tightened too much. 1 Restrictor and non-return valve, load signal line

Parking brake The adjustment below controls the application of the parking brake to make engagement of the brake softer. This function is only included on smaller machines. 1. Screw the throttle and check valve (2) to its bottom position and open it 1/4 turn. 2. Slowly run the machine forward and apply the parking brake. 3. The brake should engage softly and not cause the machine to grind to a halt. NB The more screwed in the valve is, the softer the parking brake will engage.

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Measurements and adjustments MEASUREMENT AND ADJUSTMENT OF HEAD PRESSURE (ECB) On ECB machines, the L90 valve is equipped with a pressure reducer that is set to 140 bar (does not normally need to be changed). If adjustment is necessary: 1. Connect the manometer to the test point (1) on the unit.

1 2

Test point on the unit By-pass 2. 3. 4. 5. 6.

3

Pressure reducer ECB 90

4

Pressure reducer ECB 80

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Run the spread function to the bottom. Break the plastic seal on the L90 valve Adjust pressure reducer ECB90 (3) or ECB 80 (4). Check that the pressure is 140 bar. If a whistling noise comes from the unit by-pass (2) once spreading is fully run, screw it in until the whistling stops and then turn an additional half turn.

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Measurements and adjustments MEASUREMENT AND ADJUSTMENT OF HEAD PRESSURE (GANTRY) 1. Connect a manometer to the test point (1) on the unit. 2. Run the unit to the bottom. 3. Check that the pressure is 140 bar.

1

Test point on the unit 4. Adjust the pressure on the pressure reducer (2) in the chassis.

2

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Pressure reducer

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Fault tracing FAULT TRACING Fault

Probable cause

Action

Low lifting speed

Pump/pumps not working, Incorrect standby/delta pressure

Check each pump individually Measure, adjust the pressure Check the regenerative valve, replace the valve if necessary

Regenerative valve defective

Load drops

Leaking lifting cylinder

Check for leakage, replace seals

Machine cannot lift load

Pump not giving max pressure

Adjust the pressure

Steers heavily

Variable piston pump (steering pump)

Check standby/delta pressure, max pressure Check load signal to pump Check orbitrol, steering priority valve Check for leakage, replace seals

Orbitrol, steering priority valve Leaking steering cylinder Steering bites

Pump pressure varies

Adjust the one-way restrictor on the load signal to the variable piston pump

No pressure in the accumulator

25cc gear pump defective Accumulator charging valve defective

Check the pump Check the valve

Load signal does not go down to 0 bar

Directional control valve does not go to neutral

Check the directional control valve

Load signal does not go up to max pressure

Leaking load signal Pump defective

Fault trace leakage on load Check standby/delta pressure, max pressure

Attachment runs slowly

Reduction valve for spreader Loading valve for spreader Right 60 cc pump

Check the pressure, 140 bar on spreader Check the load signal to the pump Check standby/delta pressure, max pressure

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