Onan 132-0304 Water Pump Washer
The Onan 132-0304 Water Pump Washer spreads the clamping load from its fastener, protects the surface underneath it, and in some positions provides the locking action that keeps the fastener from backing off under vibration. It is specified for its position rather than chosen by outside diameter alone.
Washers are easy to lose during a service and easy to substitute wrongly. A lock washer that has already been compressed has lost most of its spring and will not hold the fastener, and a plain washer of the wrong thickness changes the clamped stack. Fit new ones during a rebuild. This part is listed for Onan water pump 132-0284 on MAJB 2.5 and 3.0 kW generator sets. It is one of two different washers in this pump, so check the part number rather than the look of the part.
Key Features
- Correct bore, outside diameter and thickness for its position
- Spreads fastener clamping load and protects the surface beneath
- Maintains joint clamp under vibration and thermal cycling
- Direct replacement for the original Onan part
- Cheap to keep as a spare alongside pump fasteners
Applications
- Raw water pump service on Onan marine generator sets
- Reassembly after an impeller, cover or bearing change
- Replacing corroded or flattened original washers
- Building a pump spares kit for the season
Specifications
- Brand: Onan
- Manufacturer Part Number: 132-0304
- Part Type: Washer
- Fits: Onan water pump 132-0284 on MAJB 2.5 and 3.0 kW generator sets
- Quantity Per Pump: 1
- Condition: New
- Shipping Weight: 0.02 lb
Frequently Asked Questions
Q: Is stainless always the right choice?
Not always. Use the specified part, because mixing metals in a salt water environment can set up galvanic corrosion at the joint.
Q: Do I need one under every fastener?
Only where the original had one. Adding washers where none were fitted changes the clamped length of the fastener.
Q: How many should I buy?
Most owners order a small surplus, since these are easy to drop into a bilge and awkward to source in a hurry.
Q: Can I reuse a lock washer?
It is a false economy. Once compressed it has lost its spring and will not stop the fastener backing off.
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 washer.
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