Bobcat 843 Chain and Auxiliary Connector Leaks: Maintenance Insights and Field Wisdom

[MikePhua]

Bobcat 843 Chain and Auxiliary Connector Leaks: Maintenance Insights and Field Wisdom
Chain Case Rattles and Drive Chain Wear
Operators of the Bobcat 843 skid steer occasionally report hearing drive chains rubbing against the chain case, especially during turns or under load. This symptom often points to excessive slack or elongation in the chains. While some consider removing a link using an offset connector, experts caution that this is a temporary fix at best. Replacing the chains entirely is recommended, especially if the machine sees regular use.
Loose chains can accelerate wear on sprockets and axle seals, and may even compromise the integrity of the chaincase. A technician from Missouri advised inspecting the sprockets during chain replacement and considering axle seal renewal while the assembly is open—an approach that saves labor in the long run.
Auxiliary Hydraulic Connector Leaks
Another common issue involves leaking auxiliary hydraulic couplers on the front arm. These connectors are designed to be self-sealing under pressure, but accidental engagement or wear can cause fluid seepage. If the leak is persistent, replacing the couplers is often more cost-effective than attempting a rebuild.
According to Stucchi USA’s guide on hydraulic coupler leaks, operators should avoid over-tightening fittings and always depressurize the system before inspection. Using hands to detect leaks is discouraged due to the risk of fluid injection injuries—a hazard that has led to serious incidents in the past. Instead, technicians recommend using cardboard or paper to safely locate leaks.
Loopback Hose vs. Replacement
Some users consider installing a loopback hose to recycle fluid between couplers when not in use. While this can prevent leakage during idle periods, it requires purchasing two couplers, a hose, and fittings. In most cases, simply replacing the faulty couplers is more straightforward and reliable.
Chain Type and Sizing
The Bobcat 843 likely uses ANSI standard roller chains, possibly size 80 or 100 heavy-duty, though exact specifications vary by model year. Operators are advised to consult the service manual or measure the pitch and width directly. A technician in Minnesota noted that chain replacement is relatively inexpensive compared to the labor involved in accessing the chaincase.
A Story from the Field
In Massachusetts, an operator who had just rebuilt his 843 noticed both chain noise and hydraulic leaks during its first outing. After replacing the couplers and inspecting the chain tension, the machine ran smoothly for months. His experience highlights the importance of post-rebuild shakedown checks, especially on older equipment.
Industry Trends and Safety Notes
Hydraulic coupler leaks are not just a nuisance—they pose fire risks and environmental hazards. In 2024, several manufacturers began integrating connect-under-pressure couplers with improved seals and thermal resistance. These upgrades aim to reduce downtime and improve safety across job sites.
Meanwhile, Bobcat continues to refine its auxiliary hydraulic systems, with newer models featuring pressure-release buttons and color-coded couplers to simplify maintenance.
Final Thoughts
The Bobcat 843 remains a dependable machine, but like all aging equipment, it demands attention to detail. Whether you're chasing down a chain rattle or a hydraulic drip, the key lies in proactive inspection, informed part selection, and safe repair practices. With a bit of field wisdom and the right tools, even a decades-old skid steer can keep working like new.