Yamada 631421 Spring Washer for NDP-40 to NDP-80
The Yamada 631421 is the genuine replacement spring washer specified for NDP-40, NDP-50 and NDP-80 Series pumps. It is the correct grade and length for the joint it belongs to.
Tighten in sequence to the factory figure, working across the joint rather than around it. That is what keeps the clamping load even, and it matters far more on a joint sealed by an elastomer bead than on a plain metal to metal face.
Key Features
- Genuine Yamada replacement spring washer
- Fits NDP-40, NDP-50 and NDP-80 Series pumps
- 4 per pump in the assembly that uses it
- Correct grade, length and thread for the joint
- Keeps clamping load even around elastomer sealed faces
- Direct replacement for corroded, stretched or missing hardware
Applications
- NDP-40, NDP-50 and NDP-80 Series pumps
- Pump rebuilds and scheduled overhauls
- Replacing corroded or seized hardware
- Making up a complete set after a strip down
- Marine installations where corrosion takes fasteners first
- Industrial and transfer pump service
Specifications
- Brand: Yamada
- Manufacturer: Yamada America
- Manufacturer Part Number: 631421
- Part Type: Spring Washer
- Fits: NDP-40, NDP-50 and NDP-80 Series pumps
- Quantity Used: 4 per pump
- Series Port Size: 2 in on the NDP-50 Series
- Condition: New
Frequently Asked Questions
Q: What happens if one is left loose?
The clamping load is uneven, the joint weeps at that point, and the remaining fasteners carry more cyclic load than they were meant to.
Q: Can I use a standard bolt from a hardware store?
It is not advisable. Grade, length and thread are chosen for the joint, and a substitute that stretches or bottoms out changes the clamping load on a face that is sealed by an elastomer bead.
Q: Why did the original corrode so badly?
Salt air and washdown get into the threads and stay there. On marine installations the fasteners are usually the first part of the pump to need attention, well before anything internal.
Q: What torque should I use?
The factory figure for that joint, applied in sequence across the joint rather than around it. Even clamping is what keeps the sealed faces sealed.
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 spring washer.
CLRMarine
