Robbins & Myers 320-4439-001 Shaft Pin for Moyno 500 Model 367
The 320-4439-001 is the shaft pin used at the drive shaft connection on the Moyno 500 Models 36701, 36704 and 36751. It is the small hardened component that locks the flexible joint to its mating part, and it carries the full output torque of the pump across that connection every revolution.
Pins wear by working in their holes. Each revolution reverses the load slightly, and over time the pin and the bore both pick up an oval. The symptom is a knock at the pump end that comes and goes with load, and the consequence is uneven wear in the stator because the rotor no longer follows its intended path. Once a pin shows flats or a waisted section it has to be renewed, and the holes it sits in need checking for elongation at the same time. The service manuals call this the shaft pin on bare shaft pumps and the motor pin on motorised units; it is the same item in the same place.
Key Features
- Genuine Robbins & Myers Moyno replacement shaft pin
- hardened steel construction
- Fitted at the drive shaft connection of the drive train
- Matched to the Moyno 500 Models 36701, 36704 and 36751
- Removes the play that causes knocking and uneven stator wear
- Inexpensive item worth renewing whenever the joint is out
Applications
- Moyno 500 Models 36701, 36704 and 36751 progressing cavity pumps
- Renewal during a flexible joint replacement
- Curing a knock at the pump end of the drive train
- Repair after a sheared pin following a shock load
- Planned overhaul of the wet end and drive connection
- Industrial, marine and dockside pumping installations
Specifications
- Brand: Robbins & Myers
- Manufacturer: Robbins & Myers (Moyno)
- Manufacturer Part Number: 320-4439-001
- Part Type: Shaft pin
- Material: hardened steel
- Location: Drive shaft connection
- Fits: Moyno 500 Models 36701, 36704 and 36751
- Condition: New
Frequently Asked Questions
Q: Should it be replaced on a routine service?
On any service that gets as far as the joint, yes. The part is inexpensive and the labor to reach it has already been spent, so leaving an old pin in place is a false economy.
Q: Can a standard dowel or roll pin be substituted?
It is not worth the risk. These pins are hardened and sized for a specific fit in double shear, and a general purpose pin that looks identical can shear under load and take the joint with it.
Q: How many are used in a pump?
That depends on the build, since some joints are pinned at one end only and others at both. Send a picture of the pump plate and we will confirm the quantity your pump takes.
Q: The pin holes look oval. Does that matter?
Yes. A new pin in an elongated hole will be loose from the day it goes in, and the knocking returns quickly. Elongated holes usually mean the mating component needs replacing as well.
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 shaft pin before you order.
CLRMarine
