Jaw Crushers Support

Download the Jaw Crushers Troubleshooting Guide

McLanahan Corporation’s Jaw Crusher Troubleshooting Guide provides corrective actions that can be taken when troubleshooting this equipment, including what to do if the machine fails to start; if the electric motor is operating, but the pitman is not rotating; if the bearings are hot to the touch; and if there is noise at the toggle. 

Jaw Crusher Maintenance

How much, how often and what type of grease should I use?

First, always refer to the machine-specific manual. Too much or too little grease will cause high bearing temperature. The general rule for manual grease is to apply ¼lb per bearing every eight hours of operation. It is best to grease the bearings at the end of the shift while they are warm to evenly displace the grease to the bearing rollers. Over time, a wet bead or line of grease should be seen between the labyrinth seal and the bearing housing.

When your Jaw Crusher is new, use Mobilux EP2 for temperatures above 30°F and Mobilux EP1 for temperatures below 30°F. When using an automatic greaser, use Mobilux EP1 for temperatures above 30°F and Mobilux EP0 for temperatures below 30°F.

I hear a knocking sound in the crusher when it is running empty and I can't find it?

Start by loosening the tension spring assemblies and adjusting both equally compressing tension springs by ¾”. Test run the Jaw Crusher on empty and listen for the knock noise. If the knocking is still present, tighten the tension springs at ¼” rates until the knocking noise is gone. Do not exceed 1-1/2” tension spring compression.

If after adjusting the tension springs properly the knocking noise is still present, further inspection of the tension springs, rods, toggle plate, toggle seat, push beam and thrust plate is required.

How long can I run my jaw dies?

There is no set time frame, as each site’s material has different wear characteristics. An indication that your jaw die needs replaced is a drop off in production. Jaw dies have a peak and valley configuration and should be flipped or replaced before the peak is worn away to the valley.

What do I do if the bottom wears faster than the rest of the jaw die?

Remove material that is the same size as the closed-side setting of the jaw die from the feed before it enters the crushing chamber. Keep the crushing chamber two-thirds full for even wear. Also, keeping the Vibrating Grizzly Feeder bar spacing clean and open will help eliminate fine material from carrying over into the crushing chamber.

Operational Best Practices

How can I catch potential issues before they lead to downtime?

Keep a log of your Jaw Crusher’s run empty motor amperage and cost downtime to establish a baseline by which to reference. For example, if your Jaw Crusher normally runs 95 amps empty and suddenly the amps start climbing higher, you know you have an issue, either electrical or mechanical. If you have been logging your cost down time and the motor amps are climbing but the cost down time has stayed the same, this points to an electrical issue. If the motor amps climb and cost down time decreases, this is a mechanical issue. With simple checks and keeping a log of information, planned maintenance can be scheduled.

Should I keep a stock of parts on-site?

Yes. It is better to be proactive and have a stock of wear parts on-site rather than continuing to produce on worn parts and risking damage to the crusher, not to mention the lost production.

How can I minimise downtime?

Follow the manufacturer’s maintenance schedule to keep production steady. There is a good chance that when the primary crusher is down, the rest of the plant is down and production is lost.

What should I look for during the daily inspections?

  • Check that the jaw die and key/heel bolts are tight.
  • Check that the discharge area is free of buildup. Also, check the discharge setting on the jaw crusher and inspect the toggle plate for cracks.
  • Listen for any knocking sound from the toggle while the crusher is running empty, and adjust the toggle as needed.
  • Check for any unusual vibration while the crusher is running empty.
  • Lubricate the four bearings.

What items should I check during weekly inspections?

  • Log motor amps and cost downtime along with bearing temperatures.
  • Inspect the feed hopper for loose bolts and cracks.
  • Inspect the flywheels for material buildup.
  • Check the drive belt tension.

Recommended Spare Parts

McLanahan Corporation recommends that you keep certain Jaw Crusher replacement parts at your facility.

Part Name

Moveable Jaw Die Wedge, Key and Heel Wedge Bolts/Washers/Nuts 
Tension Rod Assemblies
Toggle Plate and Toggle Seat 
Stationary Jaw Die with Key/Heel Wedge Plates

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