SDLG-E6650 Track Support Roller Ass’y/Heavy duty crawler chassis components manufacture/OEM quality spare parts factory supplier

CQC’s Bottom Roller Assembly is a critical component of the undercarriage system. Its primary functions are:

• Support Weight: It bears the main weight of the excavator and distributes it evenly across the track chain.
• Guide the Track: The dual flanges on each side of the roller keep the track chain aligned and prevent it from slipping off.
• Ensure Smooth Movement: Sealed internal bearings allow the roller to rotate smoothly as the track moves.

A failure in a bottom roller can lead to accelerated wear on the entire undercarriage (track links, pins, bushings, sprockets) and even pose a risk of track derailment.

Maintenance & Inspection

Regular inspection is crucial for maximizing the life of your undercarriage, which is one of the most expensive parts of an excavator to replace.

1. Flange Wear: Measure the width of the roller’s flanges. Compare it to the specification for a new roller. Worn-down flanges can no longer guide the track properly.
2. Tread Wear: The surface of the roller that contacts the track chain should wear evenly. A convex or “dished” shape indicates significant wear.
3. Seal Failure: Look for grease leaking from the roller seals or a dry, rusty appearance around the hub. A failed seal allows contaminants in, leading to rapid bearing failure and a seized roller.
4. Rotation: The roller should turn freely. A roller that does not spin or grinds when turned is failing and must be replaced immediately.

Inspection Interval: Check undercarriage components every 10 hours in severe conditions (abrasive rock, sand) and every 50 hours in normal conditions.

4. Replacement Guidance

Replacing a bottom roller on a machine of this size is a significant task that requires proper tools and safety procedures.

Tools & Equipment Needed:

• Heavy-duty hydraulic jack and solid cribbing blocks.
• High-torque impact wrench or large breaker bar with appropriate sockets (bolt sizes are typically very large, e.g., M20+).
• A lifting device (like the excavator’s own bucket or a crane) to handle the heavy roller assembly.
• Personal Protective Equipment (PPE) – steel-toed boots, gloves, safety glasses.

General Procedure:

1. Park Safely: Position the machine on a firm, level surface. Lower the attachment to the ground.
2. Block the Machine: Chock the tracks securely to prevent any movement.
3. Relieve Track Tension: Use the grease fitting on the front idler to carefully release hydraulic pressure and slacken the track. Warning: This can release high-pressure grease, so stand clear.
4. Support the Track Frame: Place a jack and blocks under the track frame near the roller to be replaced.
5. Remove Mounting Bolts: The roller is held on by two or three large bolts that thread into the track frame. These are often extremely tight and corroded. Heat (from a torch) or a powerful impact gun is often necessary.
6. Install New Roller: Remove the old roller, clean the mounting surface, install the new roller assembly, and hand-tighten the new high-tensile bolts. Always use new bolts; reusing old ones is a safety risk.
7. Torque to Spec: Use a torque wrench to tighten the bolts to the manufacturer’s specified value (this will be a very high torque).
8. Re-tension Track: Re-pressurize the track tensioner with a grease gun to achieve the correct track sag (specified in the operator’s manual).
9. Final Check: Remove all jacks and blocks, and perform a visual check before operation.