Yamada 771344 Inner Center Disk for NDP-15
The Yamada 771344 is the genuine replacement inner center disk specified for NDP-15 Series pumps. It is one of the pair of plates that sandwich the diaphragm and connect it to the center rod.
The edge of the disk is the critical surface. Every stroke bends the diaphragm at exactly the line where the disk stops supporting it, so a burr, a lifted edge or corrosion pitting on that rim is stamped into the new diaphragm as a stress raiser and starts a crack there. Look at the rim with a fingernail rather than only with your eyes.
Key Features
- Genuine Yamada replacement inner center disk
- Fits NDP-15 Series pumps
- Two per pump
- Clamps the diaphragm bead evenly on the center rod
- Smooth support rim so the diaphragm flexes where it should
- Direct replacement, no modification required
Applications
- NDP-15 Series pumps
- Diaphragm changes and liquid end rebuilds
- Replacing a disk with a burred or corroded rim
- Service after a sudden diaphragm failure
- Restoring even clamping on the diaphragm bead
- Marine, industrial and transfer duty
Specifications
- Brand: Yamada
- Manufacturer: Yamada America
- Manufacturer Part Number: 771344
- Part Type: Inner Center Disk
- Fits: NDP-15 Series pumps
- Quantity Used: Two per pump
- Series Port Size: 1/2 in on the NDP-15 Series
- Condition: New
Frequently Asked Questions
Q: How tight should the assembly be?
To the factory torque, no more. Overtightening pinches the diaphragm bead and starts a tear at the clamp line, which is one of the most common causes of a short diaphragm life.
Q: Can I clean up a rough rim rather than replace the disk?
Light polishing of a metal disk is acceptable if it leaves a smooth radius. Anything that leaves a sharp edge or removes the radius does more harm than the original burr.
Q: Does an abrasion pad do the same job?
No. A pad sits against the diaphragm to take abrasive wear on solids laden duty, extending diaphragm life. The disk carries the clamping load.
Q: Should both sides be replaced together?
If one disk is being replaced because of damage, check the opposite one closely. They share the same stroke and usually the same condition.
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 inner center disk.
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