Onan 518-0221 Water Pump External Retaining Ring
The Onan 518-0221 Water Pump External Retaining Ring is the positive stop that keeps a bearing, seal or shaft assembly located in the pump. It is designed to sit fully in its groove with the correct free tension, which is why a reused, sprung ring is a real risk rather than a saved dollar.
Replace this ring whenever the pump is stripped to the point where it has to come out. They cost very little, they cannot be reliably inspected for lost tension, and the failure mode when one lets go is expensive. This part is listed for Onan water pumps 131-0165 and 131-0267 on MCCK 4.0 and 6.5 kW, MDJE 7.5 kW and MDJ-A, B and E generator sets.
Key Features
- Sized to the Onan pump groove diameter and thickness
- Positively locates bearings, seals or shaft components
- Correct spring tension for a secure seat in the groove
- Single use part, fitted new at every rebuild
- Inexpensive insurance against internal movement
Applications
- Raw water pump rebuilds on Onan marine generator sets
- Reassembly after bearing or seal replacement
- Replacing rings corroded or sprung during disassembly
- Stocking as a spare with pump service parts
Specifications
- Brand: Onan
- Manufacturer Part Number: 518-0221
- Part Type: External Retaining Ring
- Fits: Onan water pumps 131-0165 and 131-0267 on MCCK 4.0 and 6.5 kW, MDJE 7.5 kW and MDJ-A, B and E generator sets
- Quantity Per Pump: 1
- Condition: New
- Shipping Weight: 1 lb
Frequently Asked Questions
Q: What happens if it is not fully seated?
It can pop out under load. The part it retains then moves, and the internal clearances that keep the pump working are lost.
Q: How do I check the groove?
Clean the salt out and look for rounding, widening or corrosion pitting. A damaged groove will not hold a new ring securely.
Q: Should I keep spares aboard?
They are small and inexpensive, and they are easy to lose or distort during a job, so most owners carry one or two.
Q: Can I reuse the ring I took out?
It is not recommended. Removal spreads it, and a ring that no longer grips the groove can work loose under vibration.
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 external retaining ring.
CLRMarine
