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Introduction
This Special Instruction provides the procedure to replace 7M-8651 Armature of 123-9776 Starting Motor Armature As on all Cat® products.
Do not perform any procedure in this Special Instruction until you have read the information and you understand the information.
Safety Section
The information, specifications, and illustrations in this publication are based on information that was available at the time that the publication was written. The specifications, torques, pressures, measurements, adjustments, illustrations, and other items can change at any time. These changes can affect the service that is given to the product. Obtain the complete and most current information before you start any job. Cat dealers have the most current information available.
Work safely. Most accidents that involve product operation, maintenance, and repair are caused by failure to observe basic safety rules or precautions. An accident can often be avoided by recognizing potentially hazardous situations before an accident occurs. A person must be alert to potential hazards. This person should also have the necessary training, skills, and tools to perform these functions properly.
Safety precautions and warnings are provided in this instruction and on the product. If these hazard warnings are not heeded, bodily injury or death could occur to you or to other persons. Caterpillar cannot anticipate every possible circumstance that might involve a potential hazard.
Therefore, the warnings in this publication and the warnings that are on the product are not all inclusive. If the tools, the procedure, the work method, or your actions are not recommended by Caterpillar, ensure that the tools and your actions are safe for you and for others.
Ensure that all personnel are safe when using a tool, procedure, work method, or operating technique not recommended by Caterpillar. Ensure that the product will not be damaged or the product made unsafe by the operation, lubrication, maintenance, or the repair procedures that are used.
Note: Always use proper eye protection when performing any mechanical repairs to a vehicle and any installation or repairs to starting motors. Failure to use proper eye protection can lead to serious and permanent eye damage.
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Do not operate or work on this product unless you have read and understood the instruction and warnings in the relevant Operation and Maintenance Manuals and relevant service literature. Failure to follow the instructions or heed the warnings could result in injury or death. Proper care is your responsibility. |
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Failure to follow all safety guidelines prescribed in this document and by governing authorities and regulatory agencies may result in severe injury or death of personnel or machine damage. |
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When removing a major component or attachment, ensure that it is properly blocked or secured before removing mounting hardware. An assembly that is disconnected without proper blocking may shift or fall, resulting in serious injury or death of personnel or machine damage. |
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Personal injury or death can result from improper maintenance procedures. To avoid injury or death, follow the procedures exactly as stated below. |
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Personal injury can result from improper handling of chemicals. Make sure you use all the necessary protective equipment required to do the job. Make sure that you read and understand all directions and hazards described on the labels and material safety data sheet of any chemical that is used. Observe all safety precautions recommended by the chemical manufacturer for handling, storage, and disposal of chemicals. |
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Climbing equipment may be required to access this service point. Refer to the Operation and Maintenance Manual, "Mounting and Dismounting" topic for safety information. |
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Before servicing/performing maintenance on the machine, electrical power must be physically disconnected; battery plugs must be disconnected from the batteries, or the trailing cable must be unplugged, and warning tags and padlocks shall be applied by a certified electrician. Certified electricians shall perform or direct any electrical work, including any energized testing, repair work in controllers, motors, or other approved compartments, and shall insure that all compartments are properly closed and inspected prior to re-energization. All applicable lock out and tag out procedures must be followed. |
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Do not operate the machine if any guards or covers are missing or inadequately secured. Personnel could be seriously injured or machine damage may occur. |
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Observe the safe working load limits of all lifting and blocking devices and keep a safe distance from suspended/blocked loads. Personnel may be seriously injured or killed by falling loads. |
Machine Preparation
- Move the machine to a level surface.
- Apply parking brake. Turn engine key switch to OFF position.
Show/hide table
Illustration 1 g00104545 - Perform Lockout Tag Out procedure by attaching a warning tag to the machine controls.
Replacement Procedure
Note: Always disconnect battery ground before removing or replacing cables at the starter. Failure to disconnect the battery ground cable can lead to serious injury.
Disassembly
- Remove vehicle leads connected to the starter, noting their positions for reinstallation of starter, and remove starter.
- Remove the solenoid lead from the ground stud in the commutator end (CE) housing, and note position of the ground stud or mark the CE housing and frame for reinstallation.
- Remove six screws from the commutator end.
- Remove three plugs from the frame to allow removing three field leads to positive bushes attaching screws for 12 V, 24 V, and 32 V models or two field leads to positive brushes attaching screws for 64 V models.
- Remove the CE housing and armature assembly as a unit. It is best to remove them together to keep the brushes contained.
- Pull the brush assemblies back and contain that position with the brush springs to release the armature.
- Remove the smaller thrust washes from commutator of the armature and larger thrust washer from the DE. These washers must be placed on the new armature.
Assembly
- Apply bearing type grease onto the larger thrust washer and install onto the armature shaft DE and install the smaller brake washer onto the armature shaft CE.
- Place the armature commutator into the brush plate cavity and release the brushes.
- Apply bearing type grease onto CE housing’s outer diameter where the O-ring is seated and apply a small amount of SAE20 oil into the bushing area, being careful not to get any oil on the brushes.
- Install the CE housing, brush-plate and armature on the starter with the screws, assuring the same position as removed.
- Attach the three field leads to positive brushes with attaching screws for 12 V, 24 V & 32 V models or two field leads to positive brushes with attaching screws for 64 V models over the plug holes. Torque screws to
2.26 to 4.52 N·m (20 to 40 lb in) for punched holes or3.62 to 5.20 N·m (32.04 to 46.02 lb in) for extruded holes. These screws must be carefully aligned to prevent cross threading. - Install the six attaching screws into the CE housing and torque to
16.27 to 22.03 N·m (144.00 to 194.98 lb in) . - Install the three plugs to the frame. Torque to
8.13 N·m (71.95 lb in) . - Reinstall starter and connect cables and other leads, as removed.
- Reconnect the negative cable to the battery.