Tesco ML50-20 Guide

MAINTENANCE LIFT
Maintenance

  co 
 
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2-Contents
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Page
ML50-20 MAINTENANCE LIFT TESCO EQUIPMENT LLC
TABLE OF CONTENTS
CHAPTER 2: MAINTENANCE
PERIODIC MAINTENANCE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
HYDRAULIC OIL RECOMMENDATIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
CHECKING HYDRAULIC OIL LEVEL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
FILLING HYDRAULIC OIL RESERVOIR. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
LUBRICATION. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Grease Points . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Oil Points . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
PROCEDURE FOR BLEEDING AIR FROM HYDRAULIC SYSTEM . . . . . . . . . . . . . . . . . . . . . . . . . . 2
Bleeding Stabilizer Cylinders. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
Hi-Lift Cylinder Bleed Valve Adjustments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
HYDRAULIC ADJUSTMENTS - HYDRAULIC POWER MODULE . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
GENERAL INFORMATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
HYDRAULIC SYSTEM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
ELECTRICAL SYSTEM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
TROUBLESHOOTING GUIDE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
Troubleshooting Chart - General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
STRUCTURAL REPAIRS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Scissor arms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Scissor frame, platform . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Handrails . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Surface rust or scratches. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
HYDRAULIC SCHEMATIC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
4 Stabilizers and Return Filter - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - Figure 1 . . . . 1
ELECTRICAL SCHEMATIC. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
How to Read This Schematic - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - Figure 2 . . . . 1
ELECTRICAL SCHEMATIC - SHEET 1 OF 7 - - - - - - - - - - - - - - - - - - - - - - - - Figure 3 . . . . 1
ELECTRICAL SCHEMATIC - SHEET 2 OF 7 - - - - - - - - - - - - - - - - - - - - - - - - Figure 4 . . . . 1
ELECTRICAL SCHEMATIC - SHEET 3 OF 7 - - - - - - - - - - - - - - - - - - - - - - - - Figure 5 . . . . 1
ELECTRICAL SCHEMATIC - SHEET 4 OF 7 - - - - - - - - - - - - - - - - - - - - - - - - Figure 6 . . . . 1
ELECTRICAL SCHEMATIC - SHEET 5 OF 7 - - - - - - - - - - - - - - - - - - - - - - - - Figure 7 . . . . 1
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2-Contents
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TESCO EQUIPMENT LLC ML50-20 MAINTENANCE LIFT
ELECTRICAL SCHEMATIC - SHEET 6 OF 7 - - - - - - - - - - - - - - - - - - - - - - - - -Figure 8 . . . . . 1
ELECTRICAL SCHEMATIC - SHEET 7 OF 7 - - - - - - - - - - - - - - - - - - - - - - - - -Figure 9 . . . . . 1
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2-Figures
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ML50-20 MAINTENANCE LIFT TESCO EQUIPMENT LLC
LIST OF FIGURES
CHAPTER 2: MAINTENANCE
Section 1: Servicing
2-1 Figure 1 HYDRAULIC OIL FILL POINT......................................................................... Page 3
2-1 Figure 2 GREASE POINTS DIAGRAM ......................................................................... Page 5
2-1 Figure 3 GREASE POINTS - LIFT CYLINDER UPPER ROLLER................................. Page 6
2-1 Figure 4 GREASE POINTS - ROLERS AND PINS ....................................................... Page 7
Section 2: Hydraulic System Adjustments
2-2 Figure 1 LIFT CYLINDER BLEED VALVE..................................................................... Page 3
2-2 Figure 2 HYDRAULIC SYSTEM.................................................................................... Page 5
Section 3: Troubleshooting
Section 4: Repairs
Section 5: System Schematics
2-5 Figure 1 HYDRAULIC SCHEMATIC - ML2 WITH RETURN FILTER............................ Page 2
2-5 Figure 2 HOW TO READ THIS SCHEMATIC ............................................................... Page 5
2-5 Figure 3 ELECTRICAL SCHEMATIC - SHEET 1 OF 7 ................................................. Page 6
2-5 Figure 4 ELECTRICAL SCHEMATIC - SHEET 2 OF 7 ................................................. Page 7
2-5 Figure 5 ELECTRICAL SCHEMATIC - SHEET 3 OF 7 ................................................. Page 8
2-5 Figure 6 ELECTRICAL SCHEMATIC - SHEET 4 OF 7 ................................................. Page 9
2-5 Figure 7 ELECTRICAL SCHEMATIC - SHEET 5 OF 7 ................................................. Page 10
2-5 Figure 8 ELECTRICAL SCHEMATIC - SHEET 6 OF 7 ................................................. Page 11
2-5 Figure 9 ELECTRICAL SCHEMATIC - SHEET 7 OF 7 ................................................. Page 12
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SERVICING 2-1
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ML50-20 MAINTENANCE LIFT TESCO EQUIPMENT LLC
CHAPTER 2: MAINTENANCE
Section 1: Servicing
1. PERIODIC MAINTENANCE
Regular maintenance is required to ensure optimum performance and long life for machine components.
Maintain the unit by performing periodic maintenance at the intervals listed in the Periodic Maintenance
Chart below.
If the unit is being operated in severe weather conditions such as extreme heat or cold, or in sandy,
dusty, or snowy areas, increase the frequency of periodic maintenance as necessary.
NOTE: Refer to the chassis manufacturer’s manual for service requirements to the chassis.
PERIODIC MAINTENANCE CHART
PROCEDURE
PERIOD (HOURS)
8250 OTHER
Perform walk-around inspection and check for obvious damage,
missing parts and fluid leaks.
X
Check spotlights, indicator lights, and beacon lights. X
Check hydraulic oil level. X
Check condition of all handrails and mounting brackets. X
Check condition of operator’s boarding steps. X
Check fire extinguisher levels. Make sure they are secured in
their mounting brackets. (optional)
X
Inspect pivot pins on platform cylinders for wear. X
Check scissors pivot pins and rollers for wear. X
Inspect condition of all hydraulic hoses and fittings and check for
leakage.
X
Inspect all hydraulic components for fluid leakage. X
Check operation of the beacon light and platform work lights. X
Inspect all wiring harnesses for damage and security. X
Check operation of the platform mounted control boxes. X
Check condition of bumpers. X
Check condition of Hi-Lift/scissors structure. Check for stress
cracks, physical damage, or corrosion.
X
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MAINTENANCE
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TESCO EQUIPMENT LLC ML50-20 MAINTENANCE LIFT
CAUTION
AFTER PERFORMING MAINTENANCE ON THE HI-LIFT, DISPOSE OF ANY
ENVIRONMENTALLY SENSITIVE MATERIALS ACCORDING TO LOCAL ENVIRONMENTAL
REGULATIONS. EXAMPLES OF SUCH MATERIALS INCLUDE: BATTERIES, RUBBER BELTS,
LUBRICANTS (MOTOR OILS AND GREASE), AND HYDRAULIC OIL.
2. HYDRAULIC OIL RECOMMENDATIONS
The hydraulic oil reservoir is factory filled with ISO 15 hydraulic oil at the time of shipping.
SEVERE CLIMATE OPERATION
• If platform lowering becomes too slow in severe cold weather operations, a lower viscosity fluid
may be substituted.
Check platform understructure for cracked welds or corrosion. X
Check condition of placards and safety warning decals. X
Replace return filter 6 mos.
Check that all wiring terminals are secure. Annually
Replace corrosion inhibitor in main electrical control box. Annually
Drain hydraulic reservoir and clean. Annually
Check hoist rollers for wear X No more than
1/4” wear
OIL OPERATING TEMPERATURE RANGE
RECOMMENDED
GRADE OF
HYDRAULIC FLUID
CLIMATE AMBIENT
TEMPERATURE
MAXIMUM BULK OIL
(RESERVOIR
TEMP.)
ISO 32 Hot Above 60° F (15° C) 180° F (82° C)
ISO 15 Moderate 20° F (-7° C) -100° F (38° C) 165° F (74° C)
ISO 5 Cold Below 32° F (0° C) 150° F (60° C)
PERIODIC MAINTENANCE CHART
PROCEDURE
PERIOD (HOURS)
8250 OTHER
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SERVICING 2-1
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ML50-20 MAINTENANCE LIFT TESCO EQUIPMENT LLC
3. CHECKING HYDRAULIC OIL LEVEL
Maintaining proper hydraulic oil level is important. DO NOT overfill the hydraulic oil reservoir. Hydraulic
oil expands when heated.
1. The hydraulic oil reservoir is equipped with a sight gauge. Ensure that the Hi-Lift is fully lowered
and stabilizers must be in stowed position when checking hydraulic oil level using the sight
gauge. The oil level should be near the “High” mark and must not be below the “Low” mark.
4. FILLING HYDRAULIC OIL RESERVOIR
1. Check hydraulic oil level as described above.
2. Determine the amount of oil to be added: 1.8 gallons of oil will raise the level in the reservoir
about 1 inch.
3. Raise the van body if necessary to access the reservoir filler cap. Support platform with the main-
tenance stand.
4. Clean the area around the filler/breather cap.
5. Remove cap and check strainer screen for any foreign material.
6. Clean thoroughly before putting hydraulic oil into the reservoir.
7. Use only clean, uncontaminated oil, filtered to 10M. Add the quantity of oil determined in step 2.
8. Secure cap when finished.
9. Recheck hydraulic oil level.
Figure 1
HYDRAULIC OIL FILL POINT
HYDRAULIC FILL POINT
(HYDRAULIC OIL ONLY)
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MAINTENANCE
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TESCO EQUIPMENT LLC ML50-20 MAINTENANCE LIFT
5. LUBRICATION
A. Grease Points
NOTE: Use any commercially available “MP” multipurpose grease which meets NLGI Grade 1 or
2 standards.
Wipe grease fittings clean and apply grease. Before coating tracks with grease, clean surfaces to
remove dirt and foreign material. Refer to Figure 2 thru Figure 4.
B. Oil Points
NOTE: Use SAE 5W-30W oil with brush or oil can as appropriate.
Lift Cylinder Rods - Apply oil to reduce cylinder noise as needed which may be caused by dry
seals.
NOTE: The scissors lift must be raised to access the grease points.
NOTE: Check at intervals listed and lubricate as required. In unusual weather conditions, check at
more frequent intervals.
WARNING
THE SCISSOR LIFT MUST BE SECURED WITH THE MAINTENANCE PROP BEFORE
ACCESSING THE GREASE POINTS.
GREASE POINTS
ITEM COMPONENT TOTAL
FITTINGS INTERVAL
1 Scissor roller pins (Upper/Lower) 4 3 mos.
2 Scissor pivot pins (Upper/Middle/Lower) 8 3 mos.
3 Lift cylinder pins (Upper/Lower) 4 3 mos.
4 Scissor Arm End Pins 4 3 mos.
5 Roller Tracks 3 mos.
GREASE
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SERVICING 2-1
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ML50-20 MAINTENANCE LIFT TESCO EQUIPMENT LLC
Figure 2
GREASE POINTS DIAGRAM
1
2
2
1
2
GREASE ALL TRACKS
3
4
Ref. Figure 4
Ref. Figure 4
Ref. Figure 4
Ref. Figure 3
Ref. Figure 4
Ref. Figure 4
Ref. Figure 4
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MAINTENANCE
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TESCO EQUIPMENT LLC ML50-20 MAINTENANCE LIFT
Figure 3
GREASE POINTS - LIFT CYLINDER UPPER ROLLER
GREASE POINT
NOTE: Do not grease bleed valve shown below
BLEED VALVE
GREASE POINT
BUTT END OF CYLINDER
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SERVICING 2-1
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ML50-20 MAINTENANCE LIFT TESCO EQUIPMENT LLC
Figure 4
GREASE POINTS - ROLERS AND PINS
SCISSOR UPPER & LOWER
ROLLERS - BOTH SIDES
SCISSOR UPPER & LOWER PIVOT
PINS - BOTH SIDES
GREASE POINT GREASE POINT
REAR
FWD
SCISSOR CENTER PINS -
BOTH SIDES
UPPER AND LOWER
SCISSOR ARM END PINS -
4 PLCS
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HYDRAULIC SYSTEM ADJUSTMENTS 2-2
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ML50-20 MAINTENANCE LIFT TESCO EQUIPMENT LLC
Section 2: Hydraulic System Adjustments
WARNING
BEFORE STARTING ANY ADJUSTMENT PROCEDURE THAT REQUIRES THE PLATFORM TO
BE IN AN ELEVATED POSITION, MOVE THE MAINTENANCE STAND INTO POSITION AND
LOWER THE PLATFORM FULLY AGAINST THE MAINTENANCE PROP.
WARNING
IT IS MANDATORY THAT EYE PROTECTION (SAFETY GOGGLES OR FACE SHIELD) BE WORN
WHEN MAKING PRESSURE CHECKS AND/OR ADJUSTMENTS ON THE HYDRAULIC SYSTEM.
HYDRAULIC OIL WILL CAUSE EYE INJURIES. IF HYDRAULIC OIL GETS ON THE SKIN, WASH
AFFECTED AREA IMMEDIATELY TO AVOID IRRITATION.
WARNING
DRIVE WHEELS MUST BE CHOCKED TO PREVENT MOVEMENT OF THE UNIT IN EITHER
DIRECTION.
WARNING
WHEN MAKING PRESSURE CHECKS OR ADJUSTMENTS, USE GAUGES WITH KNOWN
ACCURACY. IMPROPER HYDRAULIC ADJUSTMENTS CAN CAUSE INJURY TO PERSONNEL
OR DAMAGE TO EQUIPMENT.
WARNING
DO NOT REMOVE GAUGE PORT PLUGS OR GAUGES, OR LOOSEN HYDRAULIC
CONNECTIONS WITH THE UNIT RUNNING. HYDRAULIC PRESSURE IN THE SYSTEMS COULD
CAUSE HYDRAULIC OIL TO SPRAY ON PERSONNEL.
CAUTION
USE EXTREME CARE TO PREVENT CONTAMINATION OF HYDRAULIC SYSTEM WHEN
INSTALLING GAUGES, FITTINGS, OR REPLACING A COMPONENT. CONTAMINATION CAN
RESULT IN EQUIPMENT DAMAGE.
CAUTION
WHENEVER AN ADJUSTABLE HYDRAULIC RELIEF VALVE OR PRESSURE REDUCING VALVE
IS REPLACED, REDUCE THE PRESSURE SETTING PRIOR TO STARTING THE UNIT. ADJUST
THE REPLACED COMPONENT TO SPECIFICATION AS OUTLINED IN THE ADJUSTMENT
PROCEDURES.
May 08
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2-2
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TESCO EQUIPMENT LLC ML50-20 MAINTENANCE LIFT
CAUTION
WHEN MAKING HYDRAULIC SYSTEM ADJUSTMENTS, THE HYDRAULIC OIL MUST BE AT
NORMAL OPERATING TEMPERATURE.
1. PROCEDURE FOR BLEEDING AIR FROM HYDRAULIC SYSTEM
A. Bleeding Stabilizer Cylinders.
Stabilizer installations for unit, are equipped with double acting rod type hydraulic cylinders.
Bleeding of double acting rod type cylinders is accomplished by cycling the stabilizers individually
10 to 15 full cycles, or until smooth operation is attained. It is important that full extension and
retraction of the rod cylinder be achieved on each cycle in order to force air out of the cylinder.
B. Hi-Lift Cylinder Bleed Valve Adjustments
(ref. Figure 1)
NOTE: Do not bleed air out of both Hi-Lift cylinders at the same time.
(1) Unload any contents from the platform to minimize the weight on the scissor lift.
NOTE: Remove “UP” limit switch on scissors in order to achieve full extension on lift cylinder.
(2) Raise the scissor to the maximum height.
(3) Secure the scissor lift with maintenance props.
(4) Leave the scissor lift at maximum height for one hour or more (leave overnight if possible)
to allow any air entrained in the hydraulic oil to rise to the tops of the cylinder.
(5) Recheck to make sure the maintenance props are in place.
(6) Put a pan under the bleeder valve to catch the hydraulic oil that is released.
(7) Open bleeder valve and keep it open until a constant stream of hydraulic oil appears with
no air bubbles.
(8) Close bleeder valve.
NOTE: Repeat bleeding procedure as required to eliminate any jerky, erratic operation of the
scissor that can be caused by trapped air.
(9) Re-install the “UP” limit switch at the pre-set position.
(10) Stow the maintenance prop.
(11) Lower the scissor to the stored position.
May 08
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HYDRAULIC SYSTEM ADJUSTMENTS 2-2
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ML50-20 MAINTENANCE LIFT TESCO EQUIPMENT LLC
(12) With the scissor in its fully lowered position, check the hydraulic oil level. Refill reservoir if
needed.
Figure 1
LIFT CYLINDER BLEED VALVE
BLEED VALVES
BLEED VALVE
DETAIL VIEW
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2-2
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TESCO EQUIPMENT LLC ML50-20 MAINTENANCE LIFT
2. HYDRAULIC ADJUSTMENTS - HYDRAULIC POWER MODULE
ITEM FUNCTION SETTING PROCEDURE
A Pressure Gauge N/A Used for reading system pressures.
B Lift Down Speed
Control
60 sec
+/- 10
-- Raise lift fully. Activate lift down function and record the time
it takes the lift to lower fully (not including stabilizer retract).
-- Adjust valve to increase/decrease lift lower speed. Loosen
locknut and turn valve clockwise to slow lift speed, counter-
clockwise to increase lift speed. Tighten locknut when
adjustment is complete.
C Main Relief 1800 PSIG
+/- 25
-- With the engine running, extend the stabilizers to the
maximum and hold control in “Extend”. Read the pressure at
the gauge.
-- To adjust the pressure, loosen the locknut on valve. Turn
valve clockwise to increase pressure, counter-clockwise to
lower pressure. Tighten locknut when adjustment is
complete.
D Stabilizer Speed
Control
(Left Rear Stab.)
N/A -- Make certain that left rear stabilizer is last to fully extend and
last to fully retract.
-- Loosen locknut and turn valve clockwise to slow stabilizer
speed, counter-clockwise to increase stabilizer speed.
Tighten locknut when adjustment is complete.
E Stabilizer
Pressure
Reducing Valves
N/A -- Fully retract lift and stabilizers. Turn valve fully clockwise and
extend/retract stabilizers till all stabilizers operate smoothly
and consistently with the left rear stabilizer last to extend and
last to retract (See Adjustment D).
-- Then turn valve counter-clockwise till chassis is lifted
between 1 & 2 in. (2.54 cm & 5.08 cm). Fully retract
stabilizers between adjustments. Chassis must be level +/- 1
in. (2.54 cm) side to side.
F Stabilizer
Pressure Switch
(Left Rear)
N/A -- Ensure Stabilizer Pressure Switch still just activates when
stabilizers are extended. Screw in adjustment to increase the
pressure needed to activate the switch. Screw out to
decrease.
-- Retract stabilizers and verify pressure switch deactivates.
G Lift Pressure
Adjustment Valve
900 PSIG
+/- 25
-- Add pressure gauge in-line to back of valve when testing for
pressure
-- Fully extend lift and read pressure on gauge.
-- Loosen the locknut and turn valve clockwise to increase
pressure and counter-clockwise to lower pressure. Tighten
locknut when adjustment is complete.
Jan. 14
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HYDRAULIC SYSTEM ADJUSTMENTS 2-2
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ML50-20 MAINTENANCE LIFT TESCO EQUIPMENT LLC
Figure 2
HYDRAULIC SYSTEM
A
B
C
D
STABILIZER
F
G
E
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TROUBLESHOOTING 2-3
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ML50-20 MAINTENANCE LIFT TESCO EQUIPMENT LLC
Section 3: Troubleshooting
1. GENERAL INFORMATION
WARNING
ONLY QUALIFIED TECHNICIANS, WHO HAVE BEEN TRAINED IN THE USE AND OPERATION
OF THIS EQUIPMENT, SHOULD ATTEMPT ANY TROUBLESHOOTING. THE CHASSIS WHEELS
MUST BE CHOCKED TO PREVENT THE HI-LIFT UNIT FROM MOVING IN EITHER DIRECTION.
THE MAINTENANCE PROP MUST BE INSTALLED FOR SUPPORT WHENEVER THE
PLATFORM IS RAISED FOR MAINTENANCE OR ADJUSTMENTS. FAILURE TO FOLLOW GOOD
SAFETY PRACTICES DURING MAINTENANCE OR TROUBLESHOOTING COULD RESULT IN
DEATH OR SERIOUS INJURY TO PERSONNEL AND/OR DAMAGE TO EQUIPMENT.
The information contained in this section is provided as a guide to assist technical service personnel in
troubleshooting operational malfunctions in the ML50-20 Lift hydraulic and electrical systems.
1. Before starting troubleshooting procedures, verify that the correct operating procedures were
used. An incorrect operating procedure can cause apparent malfunctions.
2. The most important practice to observe when working on the hydraulic system is cleanliness.
Serious damage can result quickly from foreign material in the hydraulic system. When a hydrau-
lic system is opened, cap or plug all ports and openings to keep foreign material and moisture-
laden air from entering the system. DO NOT use Teflon tape or pipe compound on straight
threads.
NOTE: Refer to the troubleshooting chapter in the chassis manufacturer’s manual for chassis
troubleshooting instructions.
May 08
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