Adjusting the tracks on a Caterpillar 312 excavator is a fundamental maintenance task essential for ensuring operational efficiency, safety, and longevity of the undercarriage components. Improper track tension accelerates wear on rollers, idlers, sprockets, and track links, potentially leading to premature failure, derailment, or increased fuel consumption. This guide outlines the systematic procedure for tension adjustment, adhering to Caterpillar’s specifications and engineering best practices.
(how to adjust tracks on 312 cat excavator)
Pre-Adjustment Preparations
1. Parking and Safety: Position the machine on a level, solid surface. Lower the bucket, boom, and stick to the ground. Engage the parking brake and shut off the engine. Remove the ignition key. Wear appropriate personal protective equipment, including safety glasses and gloves. Ensure the work area is clear of personnel and obstructions.
2. Track Inspection: Clean debris from the tracks and undercarriage. Visually inspect for damaged links, loose bolts, or excessive wear. Measure existing track sag to determine if adjustment is necessary. For the Cat 312, the standard sag specification is typically 20–40 mm (0.8–1.6 inches), measured midway between the front idler and sprocket. Use a straight edge placed across the track rails and a tape measure for accuracy. Consult the specific Operation & Maintenance Manual for model-verified tolerances.
Adjustment Procedure
The Cat 312 employs a hydraulic tensioning system using grease to actuate the front idler cylinder. Adjustment involves adding or releasing grease via a zerk fitting.
– Increasing Tension (Reducing Sag):
– Locate the grease fitting on the tensioner cylinder behind the front idler.
– Attach a high-pressure grease gun filled with Caterpillar multi-purpose grease (or equivalent meeting Cat specifications).
– Pump grease slowly in short bursts, pausing to recheck sag. Avoid over-tensioning, as excessive pressure can damage the cylinder or seals.
– Stop once sag is within the 20–40 mm range.
– Decreasing Tension (Releasing Sag):
– Place a container beneath the tensioner to catch expelled grease.
– Carefully loosen the grease fitting ¼ to ½ turn using a wrench. Do not remove it entirely.
– Allow grease to seep out incrementally. Tighten the fitting intermittently to check sag.
– Stop once desired tension is achieved. Wipe excess grease and secure the fitting.
Post-Adjustment Verification
1. Settlement Check: Operate the excavator slowly forward and backward over 10 meters to distribute grease evenly. Re-measure sag. Readjust if outside tolerance.
2. Operational Test: Perform light digging operations to confirm smooth track movement. Listen for abnormal noises indicating binding or excessive slack.
Critical Considerations
– Temperature: Adjust tracks at ambient temperature. Hot tracks expand, leading to inaccurate sag measurement.
– Avoid Over-Tensioning: Exceeding specifications strains components, increasing wear and power loss. Under-tensioning risks derailment and track slap damage.
– Grease Quality: Use only manufacturer-recommended grease. Contaminated or incompatible lubricants compromise cylinder integrity.
– Frequency: Inspect tension every 250 operating hours or weekly under severe conditions. Replace tensioner seals if grease leakage persists.
Conclusion
(how to adjust tracks on 312 cat excavator)
Precise track tension on the Cat 312 excavator optimizes traction, reduces undercarriage wear, and prevents unscheduled downtime. Adherence to prescribed tolerances, correct tools, and methodical verification ensures peak performance. Always prioritize safety protocols and consult the official Cat O&M manual for model-specific guidance. Regular maintenance records should document adjustments to track component lifecycle and inform future service intervals.