When you invest in a mobile impactor, you expect reliability, productivity, and consistent output. But like any piece of heavy equipment, even the toughest machines show signs when something isn’t right. The good news? Spotting these signals early keeps your production running smoothly and saves you costly downtime.

At RUBBLE MASTER, we know that keeping your crusher in top condition means paying attention to what your machine is telling you. 

Below are the most common warning signs that your crusher needs servicing and how to prevent bigger issues.

Unusual Sounds and Vibrations

A properly serviced impactor should run smoothly with minimal vibration. Grinding, rattling, or thumping noises usually point to mechanical issues. 

Possible causes:

• Loose or worn bearings
• Rotor imbalance caused by non-matching blow bars
• Broken blow bar
• Material blockages

Prevention:

• Regular lubrication and bolt tightening.
• Clearing debris from the crushing chamber.
• Keep the excavator cab open to listen to the machine closely during operation.

Decline in Crushing Efficiency

If your mobile impactor isn’t producing the tonnage or product quality it usually does, something is wrong.

Possible causes:

• Worn blow bars result in a too wide closed side setting and too much oversize material.
• Worn blow bars result in a too small difference between long and short hammers
• Blockages in the inlet or slabs riding on top of the blow bars
• Clogged pre-screen or finishing screen
• Slipping v-belts
• Screen meshes clogged with dirt
• Incorrect feeder speed

Prevention:

• Replace blow bars in time (see also 👉 hammer selection guide)
• Monitor the crusher inlet and outlet to identify blockages.
• Clean screen-deck regularly (e.g. remove trash).
• Adjust machine settings based on material properties.
• Adjust the closed-side setting to match wear progress.
• Tension v-belts according to the manual.

The new Setup Advisor on the latest RM 90X and RM 100X models helps you find the right setting for your application.