Bobcat T86 Brake Pack Explained

[MikePhua]

When working with heavy tracked machines like the Bobcat T86 compact track loader, the brake pack is a critical component—especially in the drive or final drive motor assemblies. Below is a detailed, self-contained explanation of what “brake pack” means for the T86, common failure modes, signs of wear, and suggestions for repair or replacement.
Overview: What Is the Bobcat T86, and Why the Brake Pack Matters
The Bobcat T86 is a powerful compact track loader introduced with modern features: a 105 hp engine, advanced hydraulics, and options for high or “super flow” auxiliary systems. It is one of Bobcat’s heaviest compact track loaders, with an operating weight around 12,393 lb (≈ 5,620 kg) and a tipping load / rated operating capacity (50% of tip) near 5,429 lb.  Because of its weight and the torque involved in driving the tracks, each drive motor must also incorporate braking mechanisms to hold or control motion when hydraulic power is neutral or off.
In a tracked machine’s drive motor (also known as a final drive or hydrostatic motor), the brake pack refers to a stack of brake discs—inner and outer friction plates—that engage to stop rotation. In effect, it’s a multi-disc wet brake (often immersed or hydraulically actuated) integrated into the drive motor. Bobcat lists a replacement brake pack for the T86 drive motor (Bobcat part number 7323045), which includes both the inner and outer brake discs, pre-stacked and ready for installation.
The brake pack is located toward the outside of the drive motor when mounted.  It is considered a typical wear component because over time the friction surfaces degrade, chip, or get scored. Bobcat’s own parts catalog includes a Pack Brake for Track Loaders 7323045 as a genuine replacement, underscoring its official role in the design.
Symptoms & Failures Reported by Owners
In one user discussion, owners expressed frustration about the inability to release the brakes on a Bobcat tracked machine once engaged:

• One contributor stated: “No way to release brakes on a Bobcat track machine... you might try using a hydraulic power pack to apply pressure to release the brakes, but it still won’t roll easily.”
  
• Another asked whether disassembling the sprockets and forcing rotation might free stuck brakes.
  

These comments reflect real field challenges: a worn or stuck brake pack will prevent even neutral hydraulic flow from allowing free rotation. Because the brake pack is frictionally engaged to hold position or resist motion, if its discs bind, the drive motor may not turn freely when desired.
Discs may chip, become warped, or get scored from contamination or misalignment. Once the brake surfaces are compromised, stopping or controlling movement becomes problematic.
Key Components & Mechanics
Within the brake pack assembly:

• Inner and outer brake discs: Alternating friction plates that clamp against housing or rotor surfaces.
  
• Pre-stacked assembly: The brake pack often comes pre-stacked so the installer doesn’t need to sort and sequence discs manually.
  
• Hydraulic actuation or pressure: In many designs, a piston or hydraulic pressure compresses the stack to engage the brake; when pressure is removed, the brake should disengage.
  
• Seals & alignment: Proper sealing, correct clearances, and good alignment are vital to prevent bleed-over, leakage, or disc contamination.
  

Inspection & Replacement Guidelines
If you suspect brake pack issues in a T86, here’s a practical workflow:

1. Remove drive motor or access brake end
   Safely support the machine and isolate hydraulic pressure before disassembly.
   
2. Inspect brake discs
   Look for chipping, scoring, uneven wear or discoloration. Any major damage means replacement.
   
3. Check surfaces they contact
   The mating rotor or housing surfaces should be flat and smooth. If damaged, resurface or replace.
   
4. Evaluate actuation mechanism
   Check the piston, seals, return springs (if present), and hydraulic lines for wear or leakage.
   
5. Compare clearance & stack height
   Ensure the reassembled stack has correct end play and clearances as per factory or parts instructions.
   
6. Install new brake pack component
   Use the pre-stacked disc pack (e.g. part 7323045) if available, lubricating lightly in accordance with Bobcat’s guidance.
   
7. Test under load and at neutral
   After reassembly, run the machine, move the tracks, and verify that when controls return to neutral, brakes fully disengage and allow free coasting (to the extent designed).
   

Preventive Measures & Best Practices

• Avoid overheating: High temperatures accelerate friction disc wear.
  
• Keep hydraulic fluid clean: Contaminants in oil can abrade disc faces and damage seals.
  
• Avoid shock loads or abrupt movements that stress brake assemblies.
  
• At rebuild intervals, preemptively replace brake pack rather than waiting for extreme symptoms.
  
• Use genuine or high-quality disc packs to maintain proper tolerances and friction performance.
  

Conclusion
For the Bobcat T86, the brake pack is a vital wear item built into the drive motor assembly. It ensures that the machine can hold its position or resist motion when needed. Over time, friction discs degrade or bind, leading to symptoms like inability to roll or brake dragging. Diagnosis involves disassembly, visual inspection of disc condition, and testing of actuation systems. Many users agree that once the brake pack is faulty, it’s time for replacement rather than repair. If you have a T86 with braking or drive issues, planning for a new brake pack (like part 7323045) is a wise step.