Case 1150 Loader Electrical Issue Resolved

[MikePhua]

Overview of the Case 1150 Loader
The Case 1150 was a sturdy crawler loader built by J.I. Case between 1960 and 1971. It came with a powerful 6.6 L, six-cylinder diesel engine producing about 105 hp gross (92 hp net), coupled with a 4-speed power shift transmission. Its open-center hydraulic system held roughly 14 gal (53 L) fluid and operated at roughly 1650 psi, delivering up to 54 gpm of pump flow . This combination made it a dependable machine on farms and construction sites of its era.
The loader used a 24-volt charging system with two 12-volt batteries, providing 575 CCA each and using a negative-ground electrical layout .
Typical Electrical Challenges
Owners have reported several electrical issues, particularly with the charging system. Common symptoms include:

• Low charging voltage or inability to recharge batteries
  
• Frequent fuse blow-outs or relays failing unexpectedly
  
• Issues correlated with aging wiring or grounding problems
  

Breaking Down Possible Causes
Several factors can contribute to electrical malfunctions:

• Alternator failure: Even mechanical alternators wear out. Check voltage output under load and inspect brushes, regulator and diode integrity.
  
• Battery degradation: A 575 CCA battery may still deliver cranking voltage but fail under recharge. Measures:
  • Load test both batteries individually
    
  • Inspect for corrosion on terminals and tighten clamps
    
• Grounding and Fuse Boxes: Voltage drop across corroded chassis or poor ground points can cause erratic behavior. Cleaning and securing grounding straps often resolves strange fuse failures.
  
• Wiring and Split Loom: As insulation ages, chafing can create shorts, particularly near the engine bay or under the hood where vibration is highest.
  

Step-By-Step Troubleshooting

• Step 1: Measure System Voltage
  With the engine running at 1500–2000 rpm, voltage at battery terminals should read around 27–28 V. Lower readings suggest alternator or regulator issues.
  
• Step 2: Inspect Battery Health
  Perform a load test. Even if the engine starts fine, batteries may not hold charge.
  
• Step 3: Review Ground and Fuses
  Clean both battery ground clamps and the main chassis ground. Remove and clean all blade-type fuses and relay sockets.
  
• Step 4: Trace Charging Circuit
  Using a voltmeter, verify voltage at alternator output, fuses, and battery line continuity. A significant voltage drop between alternator and battery needs addressing.
  
• Step 5: Swap or Rebuild Alternator
  If alternator output is weak or inconsistent, rebuilding or replacing it often restores final charging function.
  

Maintenance Tips to Prevent Future Failures

• Replace battery terminals and cables every 5–7 years to avoid corrosion buildup.
  
• Clean chassis ground points every 500 hours to prevent electrical resistance.
  
• Install an upgraded high-amp alternator or higher-gauge wiring if additional lighting or hydraulic accessories are added.
  

A Tale From the Yard
A contractor working up an old Case 1150 loader discovered that it would run all day but wouldn’t start the next morning despite clear dash lights. After replacing the batteries and cleaning the grounds—borrowed from a neighboring tractor that had already been serviced—the loader charged normally. The fix cost less than a meal but restored reliable operation.
Quick Reference

• Symptoms: Low charge voltage, intermittently blown fuses, sagging system under load
  
• Check: Voltage at engine idle vs. high RPM; battery health via load test
  
• Fixes: Clean grounding points, tighten connections, test alternator output, replace aging cables
  
• Prevent: Regular maintenance of electrical contacts during hydraulic/service intervals
  

When working on vintage machines like the 1150, addressing the electrical system head-on—in stages—usually revives stability and reliability. With basic voltmeter readings, clean connectors, and proper grounding, most Case 1150 electrical troubles are well within reach to diagnose and fix.