Yamada 770581 Check Valve Ball 35 mm, Buna-N for NDP-25 and NDP-32
The Yamada 770581 is a factory check valve ball used in NDP-25 and NDP-32 Series pumps. It is a simple part doing a demanding job - lifting off its seat and dropping back onto it on every stroke, several hundred times a minute, in whatever the pump happens to be moving.
Material choice matters here as much as anywhere in the pump. A ball has to resist the fluid chemically and resist abrasion mechanically, and it has to have enough mass to drop back onto its seat quickly at high cycle rates. Getting it wrong shows up as a pump that will not hold prime.
Key Features
- Genuine Yamada replacement check valve ball
- Material: Buna-N (NBR)
- Fits NDP-25 and NDP-32 Series pumps
- 4 per pump - two on the suction side and two on the discharge side
- Restores check valve sealing and suction lift
- Replace balls and valve seats as a matched set
Applications
- NDP-25 and NDP-32 Series pumps
- Restoring lost flow and slow priming
- Rebuilding a wet end after abrasive service
- Scheduled liquid end overhauls
- Replacing balls worn flat or undersize
- Marine, industrial and chemical transfer duty
Specifications
- Brand: Yamada
- Manufacturer: Yamada America
- Manufacturer Part Number: 770581
- Part Type: Check Valve Ball
- Material: Buna-N (NBR)
- Nominal Size: 35 mm
- Fits: NDP-25 and NDP-32 Series pumps
- Quantity Used: 4 per pump
- Series Port Size: 1 in on the NDP-25 Series
- Condition: New
Frequently Asked Questions
Q: Should all four balls be changed together?
Yes. They have done the same work, and a mixed set of new and worn balls gives uneven check action between the two chambers.
Q: Does ball wear damage anything else?
Indirectly. Operators compensate for the lost output with more air pressure, and the extra pressure is taken by the diaphragms and the center rod.
Q: How do I tell if a ball is worn?
Roll it on a flat surface and look along the edge. A worn ball wobbles or shows a dull flat band where it has been seating, and it will usually be visibly smaller than a new one when the two are held together.
Q: Do I have to replace the seats as well?
It is strongly advised. The ball and seat bed into each other, so a new ball on an old grooved seat seals against a worn profile and wears quickly to match 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 check valve ball.
CLRMarine
