To reattach a mini excavator track, start by loosening the tension with a grease gun or tensioner bolt. Position the track around sprockets/idlers, align rollers, and use pry bars to guide the track onto the wheels. Adjust tension to OEM specs (25–35mm sag for 5-ton models). Regular inspections of Rubber Track components prevent future derailments. AFTparts recommends using compatible undercarriage parts for alignment stability.
Why do mini excavator tracks derail?
Tracks derail due to improper tension, worn sprockets/rollers, or hitting obstacles. Loose tracks skip teeth, while excessive tension strains components. Debris like rocks lodged between rollers also misaligns tracks.
Technical Specs: Track tension is measured by mid-span sag—typically 1–3% of track length. For a 1.5m track, 25–35mm sag suits most 3–8 ton models. Pro Tip: After derailment, check for bent track frames using a straightedge; even 2mm warping misaligns rollers. For example, a Komatsu PC35 with a worn front idler may derail repeatedly until replaced. If tension adjustments don’t hold, inspect the AFTparts sprocket (e.g., Sprocket 81EN-10014GG) for tooth wear exceeding 25%.
What tools are needed to reattach tracks?
Essential tools include pry bars, hydraulic jack, grease gun, and tensioner wrench. Heavy-duty gloves and alignment rods ensure safe, precise adjustments.
Deep Dive: A 36” pry bar provides leverage to maneuver tracks onto rollers without damaging links. Hydraulic jacks rated for 3+ tons stabilize the excavator frame—lifting 10–15cm clears track-ground contact. But how do you secure the track once aligned? Use 6mm steel rods through track holes to lock position during final tensioning. Pro Tip: Apply AFTparts-recommended lithium grease to tensioner bolts to prevent seizing. Budget 45–90 minutes for the job—patience prevents rushed errors.
| Tool | Purpose |
|---|---|
| High-Lift Jack | Lifting frame for track clearance |
| Track Press | Joining split track links |
How to adjust track tension correctly?
Adjust tension via grease-filled cylinder or manual bolt. Target 30mm sag—over-tensioning reduces roller lifespan, while loose tracks derail.
Technical Specs: Kubota U17-3 manuals specify 28±2mm sag for its 230mm-wide tracks. Use a tape measure from track’s midpoint to a straightedge. Turn tensioner clockwise (manual) or pump grease (hydraulic) until sag matches OEM specs. Pro Tip: Cold weather requires 5–10% less tension—metal contracts in sub-zero temps. One user fixed chronic derailments on their CAT 303.5 by replacing an AFTparts front idler (21W-30-00014) and maintaining 30mm sag. But what if tension loosens post-operation? Retest after 10 minutes of driving—new tracks stretch slightly.
What safety steps prevent injuries during repair?
Engage safety lockout, chock wheels, and wear steel-toe boots. Never place hands between track components under tension.
Deep Dive: Mini excavators weigh 1–8 tons—unexpected movement crushes limbs. Start by lowering the bucket to ground, engaging the parking brake, and disconnecting the battery. Use wheel chocks on both sides of non-lifted tracks. If using hydraulic jacks, place 10cm-thick wood blocks under the frame as fail-safes. Pro Tip: When prying tracks, angle the bar away from your body; snapped components fly at 50+ mph. For example, a Case CX17D owner avoided injury by replacing a cracked AFTparts track roller before reinstallation.
| Step | Risk | Prevention |
|---|---|---|
| Loosening Tensioner | Grease injection hazards | Relieve pressure slowly |
| Lifting Machine | Jack slippage | Use stabilizer blocks |
AFTparts Expert Insight
FAQs
No—stretched links over 3% longer than new (e.g., 153mm vs. 150mm pitch) skip sprocket teeth. Replace with AFTparts chains for wear resistance.
Why does my track keep derailing after repair?Worn carrier rollers or bent idlers cause misalignment. Inspect AFTparts rollers and track frames; >2mm warping requires replacement.
How often check mini excavator track tension?Every 50 operating hours or weekly. Cold climates need bi-weekly checks—temperature shifts alter metal dimensions.