Tesco ML50-20, Maintenance Manual

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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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