Service Questions: Head Pulley Leaking Oil & Excessive Conveyor Returns

Service Questions with Mark & Louis: Head Pulley Leaking Oil & Excessive Conveyor Returns

The world of rock crushers is a place where raw power meets rugged terrain, where solid rock is transformed into valuable materials that build our world. Like any machinery, rock crushers face their fair share of challenges, and two common culprits that can disrupt their operation are head pulley oil leaks and excessive conveyor returns. Today, we’re embarking on a journey deep within the heart of the rock crushing industry to learn how to address those daunting challenges. We’ll explore the origins of these issues, and most importantly, the strategies and solutions that can help you keep your rock crusher running smoothly. So, gear up, because we’re about to discover the rock-solid solutions to these challenges in the world of rock crushers.

Why is my motorized Rulmeca head pulley leaking oil?

Service: We have seen a few in the past that had too much oil in them. When there is too much oil put in them, they build up pressure inside and force the oil out.

Q: How do I remove the excess oil?

S: All you need to do is rotate the head pulley until one of the two Allen Head Set Screws, located on the one end of the pully, are located at either 4:00 o’clock or at 8:00 o’clock. When the pulley is in this position the lower of the two screws should be removed and if the unit is overfilled, the excess oil will pour out, leaving you with the proper level of oil.

Q: How do I know it’s at the proper level of oil?

S: The proper level will be obtained when oil comes to a slow drip out of lower hole.

Q: How do I change the oil?

S: The top screw is the opening for adding oil. If it seems that the oil may have been jeopardized from excessive heat, the preferred oil is Mobil SHC630 or equivalent.

Q: What should I do if I find oil inside the electrical box?

S: According to Rulmeca, the manufacturer of the head pulley, a little bit of oil is not an issue. If there is a significant amount of oil and you are unsure, feel free to reach out to us and we will figure it out.

Q: What should I do if I want to replace the whole pulley?

S: If you are replacing one of these head pulleys, please note that on one end of the shaft there is an arrow stamped into shaft. This arrow must point towards the direction of the conveyor.  If the pulley is installed correctly the internal motor will be in the oil bath.  If it is not installed properly, the motor will burn up, causing larger issues.




I am getting a lot of returns on my conveyor. How can I minimize that?

Service: The first thing I would look at is your curtain settings. For example, if you want 1” minus I would try setting your secondary curtain to 1” and your primary curtain to 3”.

Q: How do I adjust the curtain?

S: For the secondary curtain adjustment: hydraulically extend the cylinder until the clevis lines up with the receiving hole in the rear of the bridge. Insert the retaining pin and extend the cylinder until the back set of shims, or closest to the rotor, are loose. To close the gap, remove the desired number of shims. Now, retract the cylinder and place the removed shims in the front pocket of shim box. NOTE: when moving shims, always move an equal number on each side.

For the primary curtain adjustment, start by loosening the dust covers. Under the dust covers and bridge you will find the adjusting nuts. Turn the adjusting nuts clockwise to open the setting, then counterclockwise to close the gap setting. NOTE: the gap setting is measured from the trailing edge of blow bar to the bottom edge of curtain.

Q: I did that, but now my returns are rolling down the belt.

S: Not a problem! If you have a closed-circuit plant, you can slow down the speed of your return conveyor. Slowing it down will keep the rocks from rolling down the conveyor. If you do not have a closed-circuit plant, reach out to our service department and we will figure it out together.

Q: I do have a closed-circuit plant; how do I slow down the return conveyor?

S: You can slow down the return conveyor by turning the potentiometer, which is found on the operator control panel, down. If you have any issues, give us a call!




In the demanding world of rock crushers, addressing head pulley oil leaks and excessive conveyor returns is not just an option; it’s a necessity for uninterrupted operations and profitability. As we wrap up this exploration of these challenges, remember that knowledge is your greatest tool in this endeavor. If you ever find yourself facing these issues or if you have further questions, don’t hesitate to reach out to Eagle Crusher’s experienced service technicians who specialize in rock crusher maintenance. They possess the invaluable expertise and insights needed to keep your crushing operation running smoothly, efficiently, and profitably. Your success in the rock crushing industry depends on your ability to conquer these challenges, and with the right guidance, you can ensure that your crushers keep crushing and your business keeps thriving.


The anticipation is building as the upcoming World of Asphalt / AGG1 promises a return to the thrill of in-person interactions. One of the most exciting aspects of this event is the opportunity to ask these questions face to face. The chance to approach our service technicians, engage with our sales team, and connect with like-minded individuals in real-time is sure to create a vibrant atmosphere of learning and camaraderie. As you prepare to converge in person once more, check out Eagle Crusher’s discount code to receive over 69% off your badge price.