Yamada 706375 Center Rod for NDP-50
The Yamada 706375 is a factory center rod used in NDP-50 R generation pumps. It runs through the throat bearing in the center block and carries every bit of the load the air motor produces.
The rod wears where it passes through the bearing and the packing. A scored or undersize rod will not seal against the V-packing any more, which shows up as air escaping into the wet side of the center block, or as a pump that stalls mid stroke because it is losing air past the rod. Run a fingernail along the bearing area: any ridge you can feel is enough to cut the packing.
Key Features
- Genuine Yamada replacement center rod
- Fits NDP-50 R generation pumps
- One per pump
- Ties both diaphragm assemblies into one reciprocating unit
- Ground bearing surface for correct sealing against the packing
- Direct replacement, no modification required
Applications
- NDP-50 R generation pumps
- Air motor and center block overhauls
- Replacing a scored, pitted or bent rod
- Service after product contamination of the air side
- Rebuilds following a diaphragm failure
- Marine, industrial and transfer duty
Specifications
- Brand: Yamada
- Manufacturer: Yamada America
- Manufacturer Part Number: 706375
- Part Type: Center Rod
- Fits: NDP-50 R generation pumps
- Quantity Used: One per pump
- Series Port Size: 2 in on the NDP-50 Series
- Condition: New
Frequently Asked Questions
Q: Why is the rod for PTFE diaphragm pumps different?
PTFE diaphragms have a different stroke geometry and clamping arrangement, so the rod length and thread detail differ. Match the rod to the diaphragm type the pump is built with.
Q: What causes a bent rod?
Usually hydraulic shock from a valve closed suddenly against a running pump, or reassembly with the diaphragm plates misaligned. A bent rod wears the bearing on one side only.
Q: How do I know the center rod needs replacing?
Look and feel along the section that runs in the bearing. Scoring, pitting or a ridge at the end of the stroke means the packing cannot seal against it and the rod should be replaced rather than re-packed.
Q: The pump stalls part way through a stroke. Is the rod the cause?
It can be. A worn rod lets air leak past the packing so the air motor never builds enough pressure to complete the stroke. Check the air valve and pilot valve too, since they produce the same symptom.
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 center rod.
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