Complete Guide to Removing the Starter on a CAT 931B Skid Steer

[MikePhua]

The CAT 931B Skid Steer is a reliable and durable piece of heavy equipment, commonly used for digging, lifting, and other earth-moving tasks. However, like any machine, the starter motor can eventually fail, causing difficulty in starting the engine. If you're experiencing problems with your CAT 931B and suspect the starter motor is the culprit, this guide will walk you through the process of removing and replacing it.
This article covers everything you need to know about starter motor removal for the CAT 931B, from understanding the symptoms of a faulty starter to step-by-step instructions, tools required, and helpful tips for installation.
Symptoms of a Faulty Starter on the CAT 931B
Before diving into the removal process, it's important to confirm that the starter motor is indeed the source of the problem. Some common symptoms of a faulty starter motor include:

1. Clicking Sound: When you turn the key or press the starter button, you hear a clicking noise but the engine does not turn over.
   
2. No Response: The engine does not respond at all when you attempt to start the machine, and there’s no sound from the starter motor.
   
3. Intermittent Starting: The starter motor works intermittently, and sometimes the engine starts fine while other times it doesn't start at all.
   
4. Slow Cranking: The engine cranks very slowly and struggles to start, which could indicate a problem with the starter motor or its components.
   

If you experience any of these symptoms, it's a good idea to inspect the starter motor for faults. If the starter motor appears damaged or worn out, removal and replacement are necessary.
Tools and Equipment Needed for Starter Removal
To perform the starter motor removal on your CAT 931B, you’ll need a few essential tools and equipment:

• Wrenches and Socket Set: For removing bolts and nuts.
  
• Ratchet and Extension: To reach hard-to-access bolts.
  
• Screwdrivers: To remove smaller components and electrical connections.
  
• Wire Brush: For cleaning electrical terminals and contacts.
  
• Torque Wrench: To reassemble the starter motor with the correct torque settings.
  
• New Starter Motor: If you're replacing the old one.
  
• Safety Gear: Gloves and safety glasses for protection.
  

Step-by-Step Guide to Removing the Starter Motor

1. Safety First
   • Before starting any work, ensure the skid steer is parked on a level surface and the engine is turned off. Disconnect the negative terminal of the battery to avoid electrical shorts or accidental starting of the engine.
     
   • Wear appropriate safety gear, including gloves and safety glasses, to protect yourself from any debris or sharp parts.
     
2. Locate the Starter Motor
   • The starter motor on the CAT 931B is typically located on the lower part of the engine, near the flywheel housing. It’s mounted on the engine block and secured with bolts.
     
   • Depending on the machine's configuration, it may be necessary to remove other components to gain clear access to the starter motor, such as air filters or hydraulic lines. Take care not to damage any parts during the disassembly.
     
3. Disconnect the Electrical Wiring
   • Begin by removing the electrical connections from the starter motor. Typically, there will be two connections: a large wire from the battery (positive terminal) and a smaller wire that activates the starter solenoid.
     
   • Use a wrench or socket to carefully disconnect these wires. If corrosion is present on the terminals, use a wire brush to clean the connections before removing them to avoid damage.
     
4. Remove the Starter Motor Mounting Bolts
   • The starter motor is typically secured with two or three bolts. Using a wrench or socket set, carefully remove the bolts that secure the starter motor to the engine block.
     
   • If the bolts are difficult to access, use a ratchet extension to reach the fasteners. In some cases, you may need to remove or move other components (such as air hoses or covers) to create enough space.
     
5. Remove the Starter Motor
   • Once the bolts are removed, carefully slide the starter motor away from the engine block. It may require some wiggling or slight prying to free it from its position.
     
   • Be cautious during this process to avoid damaging the surrounding components. If the starter motor is stuck, gently tap it with a soft hammer to loosen it.
     
6. Inspect the Starter Motor and Components
   • After removing the starter motor, inspect it for signs of wear, such as burnt or corroded parts. Pay close attention to the solenoid, which is the component responsible for engaging the starter motor when you turn the key.
     
   • If you find any damaged parts, it's best to replace the starter motor entirely rather than attempt repairs.
     

Installing the New Starter Motor
Once you've removed the faulty starter motor, it's time to install the new one. Here's how to properly install a replacement starter:

1. Position the New Starter
   • Position the new starter motor in place, ensuring it aligns correctly with the engine block and mounting holes.
     
   • If needed, replace any gaskets or seals that may have been disturbed during the removal process.
     
2. Secure the Starter Motor
   • Install the mounting bolts and torque them to the manufacturer’s recommended specification. Make sure the starter motor is securely fastened to the engine block.
     
   • Use a torque wrench to tighten the bolts to the correct torque to avoid over-tightening or under-tightening.
     
3. Reconnect the Electrical Wires
   • Reconnect the electrical connections to the starter motor. Start by attaching the large wire from the battery to the positive terminal on the starter.
     
   • Next, reconnect the small wire that activates the starter solenoid. Ensure the connections are tight and clean to ensure optimal performance.
     
4. Test the New Starter Motor
   • Reconnect the negative terminal of the battery and attempt to start the machine. The engine should crank and start smoothly.
     
   • If the engine does not start, double-check all electrical connections to ensure there are no loose wires or faulty connections.
     

Common Issues to Watch For
When removing and replacing the starter motor on a CAT 931B, there are a few common issues to keep in mind:

• Corroded Electrical Connections: Over time, the electrical terminals can corrode, leading to poor connections. Always inspect and clean the terminals before reinstalling the starter motor.
  
• Sticking Solenoid: If the starter motor still doesn’t engage after replacement, the solenoid may be stuck or faulty. This is a common issue, particularly in older machines.
  
• Starter Motor Failure: If your machine experiences frequent starter motor failures, it could be a sign of a larger electrical or mechanical issue, such as a faulty alternator or weak battery.
  

Conclusion
Removing and replacing the starter motor on a CAT 931B skid steer is a straightforward process, provided you follow the correct steps and use the right tools. Regular maintenance of the starter motor and electrical system can prevent unexpected breakdowns and ensure your machine starts reliably every time. Always use OEM (Original Equipment Manufacturer) parts and follow proper safety protocols to ensure a successful repair. By performing these steps yourself, you can save time and money, and keep your CAT 931B running smoothly for years to come.