Checking and adjusting track sag is vital to CTL and compact excavator maintenance.
Track that’s too tight can lead to excessive wear. If it’s too loose, the machine can feel unstable and the track can actually come loose from the sprocket. Experts at John Deere’s Commercial Worksite Products division offered the following tips for maintenance managers in the company’s Worksite Journal.
Step 1: On a CTL, bring the machine to a complete stop. Lower the boom to raise the front end of the tracks approximately 8 inches off the ground. On a compact excavator, be sure the blade is in an upward position. Then rotate the cab 90 degrees and use the bucket to carefully life one side of the machine. Turn off the engine, and safely exit the cab.
Step 2: After removing any debris between the track and the sprocket, locate the third roller from the rear of the machine and measure the distance between the bottom of the roller and the top of the track. The distance is known as your track sag.
Step 3: Check your operator’s manual for track sag specifications.
Step 4: If the track tension doesn’t match the spec, remove the cover plate located on the frame of the undercarriage (this is on CTLs only). This will give you clear visibility to the track adjuster valve and the grease fitting.
Step 5: To tighten track tension, connect a grease gun to the grease fitting and add grease until the track idler extends far enough to bring track sag within the recommended limits. To loosen track tension, slowly turn the track adjuster valve counterclockwise, which allows grease to escape through the bleed hole. When the amount of track sag is satisfactory, turn the track adjuster valve clockwise to tighten.
Step 6: With the track sag within the recommended limits, reattach the cover plate (again, on CTLs only). Repeat Steps 1 through 6 on the opposite side of the machine.
Not all undercarriages or machines are the same, so be sure to consult your owner’s manual for both specifications and proper procedures. Your dealer will also be a valuable source of information.
