Mec 3072RT User manual

SERVICE AND PARTS MANUAL
Part # 91220 R1
March 2008
3072RT / 3772RT
3772RT HD
Serial Number Range
3072RT: 9201000 - Present
3772RT / 3772RT HD: 9301000 - Present
1775ParkStreet,Suite77
Selma,California93662
Phone:[phone]Fax:[phone]
1775ParkStreet, Suite77
Selma,California93662
Phone:[phone]Fax:[phone]
ART_2497

1775 Park Street, Suite 77 • Selma, CA 93662 USA
Ph: 1-800-387-4575 • 559-891-2488 • Fax: [phone]
E-mail:[e-mail] • Web:www.mecawp.com
Aerial Platform Sales Corp.
Service Section 2
Update illustration: Deutsch Connectors
Add illustrations and update text: Continuity Checks
Page 2-3
Page 2-11
Revision History:
March 2008
Service Section 4
Update Step 3:Setting Counterbalance ValvesPage 4-11
Service Section 5
Update text: Hydraulic Schematic - bold table heads
Update illustration: Hydraulic Schematic
Update illustration: Outrigger Electric Schematic
Update illustration: Generator Option Schematic
Page 5-2
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Parts Section 1
Update illustration: Base Control Box
Update parts list to identify key switch and related components
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Parts Section 4
Update illustration: Rear Axle Assembly
Update parts list to identify valve shields and related components
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Parts Section 6
Update illustration: Base Assembly
Update parts list to identify Power to Platform Bracket
Update illustration: Control Module
Update parts list to identify Hole Plug
Update illustration: Engine, Dual Fuel
Update illustration: Engine, Dual Fuel
Update parts list to identify new part numbers
Update illustration: Engine, Diesel
Update parts list to identify new part numbers
Update illustration: Engine, Diesel
Update parts list to identify new part numbers
New illustration: Harnesses
Update parts list to identify new part numbers
Update illustration: Outrigger Install
Update parts list to identify Power to Platform Bracket
New Illustration: Generator Option, Dual Fuel
Update parts list to identify new part numbers
New Illustration: Generator Option, Diesel
Update parts list to identify new part numbers
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Reason for update
Pages
Parts Section 7
Update illustration: 3072RT Sides
Update parts list
Update illustration: 3072RT Ends
Update parts list
Update illustration: 3772RT / 3772RT HD Sides
Update parts list
Update illustration: 3772RT / 3772RT HD Ends
Update parts list
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Introduction
Update Specifications Table
Update Illustration
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Table of Contents
"3072RT / 3772RT / 3772RT HD" Service & Parts Manual - ANSI Specifications March 2008
Page i
Service Sections
INTRODUCTION ............................................................................................... I
General Safety Tips ............................................................................................... III
Hydraulic System ............................................................................................... IV
Electrical System................................................................................................ IV
Total System ....................................................................................................... IV
Machine Specifications .......................................................................................... V
Primary Machine Components ............................................................................ VII
LUBRICATION ...................................................................................................... VIII
SECTION 1:
HYDRAULIC SYSTEM ............................................................................. 1-1
Hydraulic System - General ................................................................................ 1-2
Hydraulic Fluid ..................................................................................................... 1-3
Hydraulic Fluid Reservoir ................................................................................... 1-6
Hydraulic Pump ................................................................................................... 1-7
Wheel Drive .......................................................................................................... 1-7
Parking Brake and Towing Circuit .................................................................... 1-14
Emergency Systems And Procedures ............................................................. 1-15
Steering Circuit .................................................................................................. 1-16
Platform Lift Circuit ........................................................................................... 1-18
Optional Outriggers ........................................................................................... 1-20
Cylinder Repair .................................................................................................. 1-21
Hydraulic Manifold............................................................................................. 1-24

Table of Contents
March 2008 "3072RT / 3772RT / 3772RT HD" Service & Parts Manual - ANSI Specifications
Page ii
SECTION 2:
ELECTRICAL SYSTEM ........................................................................... 2-1
Electrical System - General ................................................................................ 2-2
Deutsch Connectors............................................................................................ 2-3
Battery .................................................................................................................. 2-4
Battery Preventative Maintenance:................................................................... 2-5
Battery Replacement........................................................................................ 2-6
Alarms and Switches .......................................................................................... 2-7
Tilt Alarm .......................................................................................................... 2-8
Relays .............................................................................................................. 2-9
Limit Switch ....................................................................................................... 2-10
Optional Outriggers Switches .......................................................................... 2-10
Continuity Checks ............................................................................................. 2-11
SECTION 3:
MECHANICAL COMPONENTS ............................................................... 3-1
Torque Specifications ......................................................................................... 3-2
Mechanical Components .................................................................................... 3-3
Base/ Undercarriage ........................................................................................ 3-3
Raising the Machine ......................................................................................... 3-3
Tires ................................................................................................................. 3-4
Drive Motors ..................................................................................................... 3-5
Steer Cylinder .................................................................................................. 3-6
Hoses and Cables ............................................................................................ 3-7
Platform Removal ............................................................................................. 3-7
Lift Cylinder Removal and Installation .............................................................. 3-8
Scissor Beam Assembly................................................................................... 3-8
Engine Maintenance ............................................................................................ 3-9
Diesel Engine ................................................................................................... 3-9
Gasoline and Dual Fuel Engine...................................................................... 3-12
Outrigger Function ............................................................................................ 3-14
Outrigger Calibration ...................................................................................... 3-15
GP106 Outrigger Control Module Troubleshooting ......................................... 3-17
Outrigger Module GP106 LED Flash Codes .................................................. 3-18

Table of Contents
"3072RT / 3772RT / 3772RT HD" Service & Parts Manual - ANSI Specifications March 2008
Page iii
SECTION 4:
TROUBLESHOOTING ............................................................................. 4-1
Troubleshooting ................................................................................................... 4-3
General Troubleshooting Tips ........................................................................... 4-3
Common Causes of Hydraulic System Malfunctions:....................................... 4-3
Hydraulic Pressure Adjustment Procedures..................................................... 4-9
Proportional Speed Adjustment ....................................................................... 4-12
Controls and Switches ...................................................................................... 4-14
SECTION 5:
SCHEMATICS ..........................................................................................5-1
Hydraulic Schematic ........................................................................................... 5-2
Main Hydraulic Manifold ................................................................................... 5-4
Optional Outriggers Hydraulic Manifold ............................................................ 5-5
Electric Schematics ............................................................................................. 5-6
Circuit Board .................................................................................................... 5-8
Controls .......................................................................................................... 5-10
Engine ............................................................................................................ 5-13
Optional Outriggers ........................................................................................ 5-15
Optional Generator ......................................................................................... 5-16

Table of Contents
March 2008 "3072RT / 3772RT / 3772RT HD" Service & Parts Manual - ANSI Specifications
Page iv
Parts Sections
SECTION 1: CONTROL BOXES
SECTION 2: PLATFORM AND RAILS
SECTION 3: SCISSORS
SECTION 4: AXLES
SECTION 5: HYDRAULICS
SECTION 6: BASE
SECTION 7: DECALS

"3072RT / 3772RT / 3772RT HD" Service & Parts Manual - ANSI Specifications March 2008
Page I
INTRODUCTION
This manual consists of Service and Parts illustrations sections.
The Service Section of this manual is designed to provide you, the customer, with the instructions
needed to properly maintain the MEC self-propelled scissors lift. When used in conjunction with
the illustrated parts section and the Operators Manual (provided separately), this manual will
assist you in making necessary adjustments, repairs, identifying, and ordering the correct re-
placement parts.
All parts represented here are manufactured and supplied in accordance with MEC’s quality
standards.
We recommend that you use Genuine MEC parts to insure proper OPERATION and reliable
PERFORMANCE.
To obtain maximum benefits from your MEC scissors lift, always follow the proper operating and
maintenance procedures. Only trained authorized personnel should be allowed to operate or
service this machine. Service personnel should read and study the Operator’s, Service and Parts
Manuals in order to gain a thorough understanding of the unit prior to making any repairs.
To help you recognize important safety information, we have identified warnings and instructions
that directly impact on safety with the following signals:
“DANGER” INDICATES AN IMMINENTLY HAZARDOUS SITUATION
WHICH, IF NOT AVOIDED, WILL RESULT IN DEATH OR SERIOUS
INJURY. THIS SIGNAL WORD IS LIMITED TO THE MOST EXTREME
SITUATIONS.
“WARNING” INDICATES A POTENTIALLY HAZARDOUS SITUATION
WHICH, IF NOT AVOIDED, COULD RESULT IN DEATH OR SERIOUS
INJURY.
“CAUTION” INDICATES A POTENTIALLY HAZARDOUS SITUATION
WHICH, IF NOT AVOIDED, MAY RESULT IN MINOR OR MODERATE
INJURY. IT MAY ALSO BE USED TO ALERT AGAINST UNSAFE
PRACTICES. “CAUTION” IS USED FOR PROPERTY-DAMAGE ONLY
ACCIDENTS.

March 2008 "3072RT / 3772RT / 3772RT HD" Service & Parts Manual - ANSI Specifications
Page II
NOTE: The best method to protect yourself and others from injury or death is to use
common sense. If you are unsure of any operation, don’t start until you are satis-
fied that it is safe to proceed and have discussed the situation with your supervi-
sor.
Service personnel and machine operators must understand and comply with all warnings and
instructional decals on the body of the machine, at the ground controls, and platform control
console.
MODIFICATIONS OF THIS MACHINE FROM THE ORIGINAL DESIGN
AND SPECIFICATIONS WITHOUT WRITTEN PERMISSION FROM
MEC ARE STRICTLY FORBIDDEN. A MODIFICATION MAY
COMPROMISE THE SAFETY OF THE MACHINE, SUBJECTING
OPERATOR(S) TO SERIOUS INJURY OR DEATH.
MEC’s policies and procedures demonstrate our commitment to Quality and our relentless ongo-
ing efforts towards Continuous Improvement, due to which product specifications are subject to
change without notice.
Any procedures not found within this manual must be evaluated by the individual to assure one-
self that they are “proper and safe.”
Your MEC Scissors Lift has been designed, built, and tested to provide many years of safe, de-
pendable service. Only trained, authorized personnel should be allowed to operate or service the
machine.
MEC, As Manufacturer, Has No Direct Control Over Machine Application And Operation. Proper
Safety Practices Are The Responsibility Of The User And All Operating Personnel.
If There Is A Question On Application And/Or Operation Contact:
Aerial Platform Sales Corp.
1775 Park Street, Suite 77 • Selma, CA 93662 USA
Ph: 1-800-387-4575 • 559-891-2488 • Fax: [phone]
www.mecawp.com

"3072RT / 3772RT / 3772RT HD" Service & Parts Manual - ANSI Specifications March 2008
Page III
GENERAL SAFETY TIPS
Regular inspection and conscientious maintenance is the key to efficient economical operation of
your scissors lift. It will help to assure that your equipment will perform satisfactorily with a mini-
mum of service and repair.
The actual operating environment of the machine governs the inspection schedule. Correct lubri-
cation is an essential part of the preventative maintenance to minimize wear on working parts
and ensure against premature failure. By maintaining correct lubrication, the possibility of me-
chanical failure and resulting downtime is reduced to a minimum.
NEVER PERFORM SERVICE ON THE MACHINE (WITH THE
PLATFORM ELEVATED) WITHOUT FIRST BLOCKING THE BEAMS
(SCISSORS) ASSEMBLY IN PLACE USING THE MAINTENANCE
LOCK!
•Block scissors assembly using Maintenance Lock if
machine is in the elevated/extended position.
•Never leave hydraulic components or hoses open.
They must be protected from contamination (includ-
ing rain) at all times.
•Never open a hydraulic system when there are con-
taminants in the air.
•Always clean the surrounding area before opening
hydraulic systems.
•Use only recommended lubricants. Improper lubri-
cants or incompatible lubricants may be as harmful
as no lubrication.
•Watch for makeshift “fixes” which can jeopardize
safety as well as lead to more costly repair.
Maintenance Lock In Position
3072RT
3772RT

March 2008 "3072RT / 3772RT / 3772RT HD" Service & Parts Manual - ANSI Specifications
Page IV
Hydraulic System
HYDRAULIC FLUID UNDER PRESSURE CAN PENETRATE AND
BURN SKIN, DAMAGE EYES, AND MAY CAUSE SERIOUS INJURY,
BLINDNESS, AND EVEN DEATH.
CORRECT LEAKS IMMEDIATELY.
Hydraulicfluid leaks under pressure may not always be visible.
Check for pin hole leaks with a piece of cardboard, not your hand.
Electrical System
Prevent damage to battery and/or electrical system;
• Always disconnect the negative battery cable first.
• Always connect the positive battery cable first.
If contact is made between the positive side of the battery and a metal surface on the machine
when the negative cable is installed a spark will occur. This can cause damage to the electrical
system, battery explosion, and personal injury.
Total System
Engine coolant level must be checked only after engine has cooled.
If radiator cap is removed while the coolant is at normal operating
temperature, pressure within the coolant system will force hot liquid
out through the filler opening and possibly cause severe scalding.
Failure to perform preventive maintenance at recommended
intervals may result in the unit being operated with a defect that
could result in injury or death of the operator.
Immediately report to your supervisor any Defect or malfunction.
Any defect shall be repaired prior to continued use of the scissors
lift.
Inspection and maintenance should be performed by qualified
personnel familiar with the equipment.