Mellott and Marion Machine LLC: Our Expert Approach to Symons 7′ Rebuilds

Cone crushers have a rich history in the aggregate industry. While some crushers have diminished in popularity over time, a specific cone crusher remains a top choice: The Symons 7 Foot Cone Crusher, commonly known as the Symons 7’. Our company alone has over 100 of these machines in our records. With its secondary, tertiary, and quaternary applications, it’s no wonder so many players in the industry use this large crusher.

Unfortunately, even the most popular and reliable pieces of equipment can fall victim to wear and tear. Since many Symons 7’ circulating today have been in use since the 1900s, most are in dire need of repairs on the machinery and upgrades on antiquated components.

Over the last decade, Mellott and Marion Machine LLC  has created an extensive rebuild process for these large cone crushers, with Marion and Mellott functioning as a team to complete the rebuild.  That is why when a customer came to us with a rebuild request, our teams were ready.

The customer had several safety and efficiency concerns. With those needs in mind, our Mellott Service Technicians worked hard to deliver a user-friendly and completely OEM-authorized Symons 7’.

This process involved many moving parts, multiple locations, and months of work. But it all started with a basic evaluation.

  1. Initial Evaluation by Experts This careful evaluation of the cone crusher in question is essential to the rest of the rebuild. It allows our experts to understand how much repair each crusher component requires. Because of the size and weight of the Symons 7’, a field disassembly was needed. Once this was completed, the various parts were shipped to our facility in Warfordsburg, PA. While there, each part of the machine, including the mainframe, adjustment ring, bull, eccentric, main shaft/head assembly, and counter box assembly, was examined.  During the evaluation, the components were measured by our large-scale specialized instruments. These measurements are taken for all our rebuilds to ensure OEM specifications and provide data for any replacement parts. After these tasks were completed, our Mellott Company team delivered a quote to the customer for the repairs. The quote was accepted, and the cone crusher was stripped entirely for the next part of the rebuild process.
  1. Machining for Maximum Efficiency and Safety The next part of this Symons 7’ rebuild included a trip to North Carolina. At our Southern Service Center, Marion Machine, the frame was machined and sandblasted as needed. Once our team in NC sent the frame back to our PA campus, the machine components were altered and reassembled with a couple of key improvements and modifications. These vital improvements included: Bushings Replacements Our Mellott Company technicians installed bronze bushings throughout the frame and secondary components for this rebuild and most of the others. These bushings are designed to be the soft, wearable pieces to the Symons 7’ puzzle. They are lubricated to protect each part of the crusher from severe wear. With these bushings in place, the giant machine won’t damage itself from the considerable friction and pressure exerted during operation. Hydraulic Upgrade This improvement was specifically requested for the rebuild, but most of our Symons 7’ rebuilds include it. Our Mellott technicians replaced a spring clamp system with a hydraulic system. This system upgrade vastly improves the cone crusher’s ability to deal with tramp iron, also known as uncrushable material. Tramp iron can introduce safety and delay issues during a crushing operation. 

    Before the hydraulic change, many customers will try to cut out the obstruction(s) themselves. This can relieve pressure on the crusher’s cavity very quickly. Pressure with that speed can be hazardous to whoever is cutting the tramp iron out. Our hydraulic system makes it much easier to do this by lifting the machine and relieving the pressure slowly in the cavity. The hydraulics allow any tramp irons to pass through cleanly and safely.

    This also saves downtime because any tramp irons or other obstructions can be cleared in 30 minutes instead of the 8 hours it would have taken without the hydraulics. These changes significantly increased this Symons 7 foot’s utilization and safety.

    After our service technicians added these improvements, the crusher was moved into the final rebuild step: Careful Field Reassembly, Installation, and Revaluation

    After our technicians painstakingly reassembled smaller components, the Symons 7’ was shipped back to the customer’s site the same way it left—in pieces.  Our team then reassembled the larger pieces that were sent. The next step was installation and field assembly. The installation aspect of the rebuild included final touches.

    • Our technicians conducted a careful inspection of the whole unit to make sure all sensor systems, oil flows, and pressure systems were functioning properly.
    • They also tested the crusher to ensure all the new bushings were commissioned and installed correctly.
    • Our team made sure the upgraded crusher was ready overall for optimal use by our customers.


    With each rebuilding step completed, this Symons 7’ was ready to do what it does best: crush!

    Looking for Cone Crusher Repairs?

    We hope this information has been helpful as you consider any Symons 7’ or other rebuild needs at your site.

    If you’re considering requesting a rebuild or have questions about our process, get in touch with us. At Mellott Company, and Marion Machine LLC,  we’re experts at navigating all of the different components of crusher rebuild, repairs, and assembly. We can guide you through how your cone crushers or other equipment can be improved and maintained.

    Get in touch with us today online or at 1-800-627-1639, and make sure your Symons 7’ is functioning at industry standard levels.

Our Metso HP 800 Mainframe had a loose shaft and we re-fit the shaft back to OEM specs with a 2-week-turnaround to get a 3.5-million-ton-plant back up and running.

Christopher Joyce Vulcan Materials of Winston-Salem, NC

We believe in Safety, Integrity, Commitment, Respect, and Excellence.