Service & Parts
Gear Pump Service Kits & Repair Kits
Factory-matched rebuild kits for NAPCO 2-inch and 3-inch rotary gear pumps. One kit restores gears, bearings, seals, and gaskets in the field.
A gear pump service kit rebuilds a worn NAPCO rotary gear pump without buying a new unit. Match the kit to the pump: PK200C/PK200S for PA200, PK300C/PK300S for PA300. Each kit includes the drive and idler gear assemblies, roller bearings, mechanical seals, centercase gaskets, and 4 PB43 cover bolt O-rings. A typical rebuild takes 2–5 hours with hand tools and costs about 30–50% less than a replacement pump. For emulsion and stainless duty, start with PK300S on PA300S.
Why Rebuild Instead of Replace?
NAPCO repair kits restore a worn rotary gear pump to factory performance for less than a new pump. Most rebuilds finish on-site in 2–5 hours with standard hand tools. You keep the housing and piping in place. See pump repair kit vs replacement and the gear pump rebuild guide.
Choose Your Kit
Match your pump model to the corresponding repair kit. The first digit indicates port size (200 = 2-inch, 300 = 3-inch) and the suffix indicates material (C = ductile iron, S = stainless steel).
2-Inch Pump Kits (PK200 Series)
PK200C, Ductile Iron
For PA200C pumps. Includes PA250C/PA251C drive and idler gear assemblies on ductile-iron shafts (nitrile gears; Viton optional), PM038 bearings, PM036/PM037 seals, centercase gaskets, and 4 PB43 cover bolt O-rings.
Best for: petroleum, lubricants, waste oil, adhesives plant transfer
View kit details →PK200S, Stainless Steel
For PA200S pumps. Includes PA250S/PA251S drive and idler gear assemblies on induction-hardened stainless shafts (nitrile gears; Viton optional), PM038 bearings, PM036/PM037 seals, centercase gaskets, and 4 PB43 cover bolt O-rings.
Best for: chemicals, solvents, food-grade fluids, corrosive liquids, emulsion transfer on 2-inch lines
View kit details →3-Inch Pump Kits (PK300 Series)
PK300C, Ductile Iron
For PA300C pumps. Includes PA350C/PA351C drive and idler gear assemblies on ductile-iron shafts (nitrile gears; Viton optional), bearings, seals, centercase gaskets, and 4 PB43 cover bolt O-rings. Kit weight approximately 34 lb.
Best for: high-volume fuel transfer, heavy industrial fluids, adhesives
View kit details →PK300S, Stainless Steel
For PA300S pumps. Includes PA350S/PA351S drive and idler gear assemblies on induction-hardened stainless shafts (nitrile gears; Viton optional), bearings, seals, centercase gaskets, and 4 PB43 cover bolt O-rings.
Best for: emulsion explosives / ammonium nitrate blends, chemical transfer, corrosive high-volume duty
View kit details →What’s in Every NAPCO Service Kit
Drive & Idler Gear Assemblies
Gear assemblies on ductile-iron or induction-hardened stainless shafts. Standard gears are nitrile. Viton optional where approved.
Front & Rear Bearings
Roller bearings (PM038) rated for continuous operation up to 100 PSI
Mechanical Seals
PM036 and PM037 seals that prevent leakage at the drive shaft entry point
Gaskets & Cover Bolt O-rings
Centercase gaskets (PM007G01 / PM007G02) and 4 PB43 cover bolt O-rings
Ductile Iron vs. Stainless Steel Kits
Ductile Iron (C)
- Corrosion Resistance
- Moderate. Suited for petroleum-based and non-corrosive fluids
- Typical Applications
- Fuel transfer, lubricants, waste oil, adhesives
- Temperature Range
- Standard industrial temperatures
- Cost
- Lower cost option
Stainless Steel (S)
- Corrosion Resistance
- High. Resists acids, solvents, and corrosive chemicals
- Typical Applications
- Chemical processing, food & beverage, pharmaceuticals, solvents
- Temperature Range
- Wider range including hot chemical processes
- Cost
- Premium. Justified when corrosion resistance is critical
| Feature | Ductile Iron (C) | Stainless Steel (S) |
|---|---|---|
| Corrosion Resistance | Moderate. Suited for petroleum-based and non-corrosive fluids | High. Resists acids, solvents, and corrosive chemicals |
| Typical Applications | Fuel transfer, lubricants, waste oil, adhesives | Chemical processing, food & beverage, pharmaceuticals, solvents |
| Temperature Range | Standard industrial temperatures | Wider range including hot chemical processes |
| Cost | Lower cost option | Premium. Justified when corrosion resistance is critical |
Not sure which material is right for your application? See our Stainless Steel vs. Ductile Iron guide for a detailed comparison.
Emulsion and Stainless Rebuilds
Plants that run stainless PA300S or PA200S on emulsion or ammonium nitrate duty rebuild with the matching S kit, not a C kit.
PK300S rebuilds PA300S (up to 158 GPM @ 280 RPM). PK200S rebuilds PA200S on smaller lines. Use stainless housings and the S gear set when ammonium nitrate or corrosive oxidizer blends are in the fluid. For the buyer path on emulsion transfer, see explosives & mining and PA300S. Kit SKU page: PK300S. Surface and plant transfer only. Not borehole injection.
When to Rebuild Your Pump
Gear pumps are designed for long service life, but internal wear is inevitable, especially in abrasive or high-viscosity applications. Common signs that a rebuild is needed include declining flow rate at normal operating speed, increased noise or vibration, visible leakage at the shaft seal, and higher-than-normal power draw from the motor.
For a detailed checklist of wear indicators, read our guide: 5 Signs Your Gear Pump Needs a Rebuild. For an economic analysis comparing rebuild vs. replacement, see our rebuild vs. replace cost analysis.
Related Guides
Gear Pump Rebuild Guide
Step-by-step PA200 and PA300 field rebuild procedure
Repair Kit vs. Replacement
When a kit is enough and when the housing should be replaced
Field Maintenance Guide
Step-by-step field maintenance procedures for rotary gear pump systems
How Rotary Gear Pumps Work
Drive and idler gears, displacement, and why kits restore flow
Explosives & Mining
Stainless rebuild path for emulsion and ammonium nitrate transfer
PA300S
3-inch stainless pump. Rebuild with PK300S.
PK300S
Stainless service kit for PA300S emulsion and chemical duty
PA200S
2-inch stainless pump. Rebuild with PK200S.
PK200S
Stainless service kit for 2-inch emulsion and chemical lines
Pump Identification Guide
Identify your pump model, material, and port size from the nameplate
FAQs
What is in a NAPCO gear pump service kit?
Drive and idler gear assemblies, roller bearings, high- and low-pressure seals, centercase gaskets, and 4 PB43 cover bolt O-rings. Kits do not include the pump housing, end covers, wear plates, or assembly lubricant.
Which kit fits my pump?
Match port size and material. PA200C → PK200C. PA200S → PK200S. PA300C → PK300C. PA300S → PK300S. The first digit is port size; C is ductile iron; S is stainless.
How long does a rebuild take?
Most field rebuilds take 2–5 hours with standard hand tools when the kit matches the pump.
Is a rebuild cheaper than a new pump?
A typical rebuild runs about 30–50% less than buying a replacement pump, and you keep the installed housing and piping.
Which kit for emulsion explosives transfer?
Stainless duty: PK300S for PA300S, or PK200S for PA200S. See the explosives hub for plant and surface transfer context. Not for borehole injection.
Do you ship kits separately from pumps?
Yes. Repair kits are ordered by part number and ship when in stock. Lead times on pumps stay 6–8 weeks unless stock says otherwise.
Need a Repair Kit?
Contact NAPCO directly for pricing, availability, and technical support. Standard lead time is 6–8 weeks.
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