Troubleshooting Charging and Final Drive Issues on the Takeuchi TB015

[MikePhua]

The Takeuchi TB015 and Its Compact Excavator Legacy
The Takeuchi TB015 is a compact excavator introduced in the early 2000s, designed for tight-access jobs in landscaping, utility trenching, and small-scale demolition. Takeuchi, founded in Japan in 1963, pioneered the compact excavator category and remains a respected name in precision hydraulic equipment. The TB015, weighing approximately 1.5 metric tons, features a swing boom, rubber tracks, and a simple mechanical layout that appeals to owner-operators and small contractors.
Despite its compact size, the TB015 is built with a full-featured hydraulic system and planetary final drives. Like many machines in its class, it can suffer from electrical charging issues and final drive seal failures—especially as it ages or is exposed to harsh environments.
Battery Charging Failure and Alternator Access Challenges
One common issue reported by TB015 owners is the battery failing to charge during operation. In some cases, the alternator warning light is non-functional due to a blown bulb, masking the underlying problem. When the engine is running, no voltage reaches the battery, suggesting either a failed alternator or a broken voltage regulator.
Key diagnostic steps:

• Measure voltage at the battery terminals with the engine running (should exceed 13.5V)
  
• Inspect alternator belt tension and condition
  
• Check for corrosion or loose connections at the alternator terminals
  
• Confirm whether the voltage regulator is internal or external to the alternator
  

Accessing the alternator on the TB015 can be difficult due to its location beneath the seat and body panels. Removing the ROPS canopy and side panels may be necessary. Some operators have opted for temporary solutions like solar trickle chargers to maintain battery voltage during short-term use, especially when lighting systems are not required.
Final Drive Gear Oil Blockage and Seal Leakage
Another issue involves the final drive gear oil system. On one side, the gear oil drains and fills normally. On the other, no oil flows in or out, and attempts to inject gear oil result in leakage from the center of the track area. This suggests a failed seal or blocked internal passage.
Upon removing the front cover, the drive appears packed with sludge and mud, indicating contamination and possible seal degradation. The final drive uses a planetary gear system housed in a sealed unit, and the seal failure allows gear oil to escape into the track area.
Terminology:

• Final drive: A gear reduction unit that transmits hydraulic motor torque to the track sprocket
  
• Planetary gears: A gear system with a central sun gear surrounded by planet gears, used for torque multiplication
  
• Brass bushing seal: A two-part seal system using brass rings and an O-ring to prevent oil leakage
  

Disassembly and Seal Replacement Procedure
To access and replace the failed seal, the following steps are recommended:

• Retract the idler and remove the track
  
• Unbolt and remove the final drive cover (typically held by hex screws)
  
• Extract the planetary gear set and sun gear
  
• Remove the large snap ring using heavy-duty snap ring pliers
  
• Separate the outer hub and track driver from the machine
  
• Remove the bearings and inspect for wear or damage
  
• Replace the brass bushing seal and O-ring
  

Some technicians report that the bearings in the TB015 final drive are prone to failure every few years due to stress and contamination. When bearings fail, they often destroy the seal, making seal-only replacement ineffective. A full rebuild with new bearings and seals can cost over $1,500 in parts alone, with Takeuchi bearings priced at $400+ each and seals exceeding $500.
Temporary Solutions and Project-Based Repairs
For operators needing short-term functionality, filling the final drive with 00 grease—a semi-fluid lubricant—can provide temporary protection. While not ideal, this method allows the machine to operate without immediate seal replacement. Grease flows slowly and may not leak through a failed seal as readily as gear oil.
In one case, a user flushed the contaminated drive, filled it with 00 grease, and completed a summer project without further leakage. No metal fragments were found during flushing, suggesting internal gears were intact.
Starter and Alternator Access Lessons
Accessing electrical components like the starter and alternator often requires significant disassembly. Removing the ROPS, seat, and surrounding panels is necessary to reach the starter motor. One operator reported replacing the starter after a failure in a muddy excavation site, learning the machine’s layout through hands-on experience.
Tips for electrical service:

• Use local rebuild shops for alternator and starter replacements to avoid OEM markup
  
• Label wires and take photos during disassembly to aid reassembly
  
• Replace corroded terminals and use dielectric grease to prevent future issues
  

Conclusion
The Takeuchi TB015 remains a capable compact excavator, but age-related issues like charging failure and final drive seal leaks can complicate ownership. With methodical diagnostics, temporary workarounds, and a willingness to disassemble, many problems can be addressed without full component replacement. For operators balancing budget and performance, the TB015 offers a platform that rewards mechanical curiosity and practical ingenuity. In compact excavation, sometimes the smallest machine teaches the biggest lessons.