Robbins & Myers 320-6515-000 Fluoroelastomer Flexible Joint for Moyno 500 Model 36701
This FPM fluoroelastomer flexible joint couples the drive shaft to the rotor in the Moyno 500 Models 36701 and 36751. Torque passes straight through it while the joint absorbs the orbiting movement of the rotor inside the stator. Without it the rotor could not follow its path and the pumping element would bind within a few revolutions.
Joints wear because they never stop articulating. Every revolution flexes the boot and works the internal bearing surfaces, and abrasive liquid that finds its way past a split boot accelerates the process sharply. The early sign is a knock or clatter at the pump end that changes with speed, and the late sign is a joint that lets go completely and leaves the rotor turning freely inside the stator with no output at all. Inspect the boot for splits and the joint for free play whenever the wet end is opened.
Key Features
- Genuine Robbins & Myers Moyno replacement flexible joint
- FPM fluoroelastomer construction
- Sized for the Moyno 500 Models 36701 and 36751 drive train
- Transmits full pump torque while absorbing the eccentric rotor motion
- Removes the play that causes knocking and uneven stator wear
- Direct replacement, no modification required
Applications
- Moyno 500 Models 36701 and 36751 progressing cavity pumps
- Replacing a joint with a split boot or visible free play
- Curing a knock or clatter at the pump end of the drive
- Routine renewal during a stator and rotor rebuild
- Restoring drive to a pump that turns but produces no flow
- Industrial, marine and dockside pumping installations
Specifications
- Brand: Robbins & Myers
- Manufacturer: Robbins & Myers (Moyno)
- Manufacturer Part Number: 320-6515-000
- Part Type: Flexible joint, rotor to drive shaft
- Material: FPM fluoroelastomer
- Quantity Used: One per pump
- Fits: Moyno 500 Models 36701 and 36751
- Condition: New
Frequently Asked Questions
Q: Why does a split boot matter if the joint still drives?
Because the boot is what keeps lubricant in and the pumped liquid out. Once it splits, grit reaches the working surfaces and the joint moves from gradual wear to rapid failure, usually within a small fraction of its normal life.
Q: Should the joint be renewed every time the stator is changed?
On abrasive or heavily loaded duties it is good practice, since the labor is already paid for and the joint is only reachable with the wet end open. On clean light duty a careful inspection for play and boot condition is usually enough.
Q: What makes the carbon steel and stainless versions different?
Material choice follows the liquid and the rest of the pump build rather than performance. A stainless joint suits corrosive and washdown service where a carbon steel one would rust, and the two carry separate part numbers for that reason.
Q: The pump turns but nothing comes out. Could the joint be the cause?
It is one of the first things to check. A joint that has failed completely leaves the shaft turning while the rotor stays still or wanders, so the pump sounds normal and delivers nothing. Turn the shaft slowly by hand and watch whether the rotor follows it.
Not sure this is the right part? Send us a Picture of the pump plate on your pump and the CLR Marine team will confirm the correct flexible joint before you order.
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