8-97136574-0 OEM Fit Power Steering Pump 4HF1 4HE1 4HG1T Engine Compatible 100 bar Maximum Pressure Steering Oil Pump for ISUZU NPR NQR NPS
| Pump Type: | Vane-Type Hydraulic Pump | Nominal Displacement: | 7.0 Ml/r |
| Controlled Flow Rate: | 8.0 L/min | Maximum Pressure: | 100 Bar |
| Speed Range: | 500–5000 R/min | Inlet Port Size: | 17.5 Mm |
| Outlet Thread: | M12 × 1.25 | Rotation Direction: | Left-Hand |
| High Light: | 8-97136574-0 OEM Fit Power Steering Pump,4HF1 4HE1 4HG1T Engine Compatible Steering Oil Pump,100 bar Maximum Pressure Power Steering Pump |
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The Power Steering Oil Pump with OEM numbers 8-97136574-0 and 8971365740 is a verified direct-fit replacement for ISUZU NPR / NQR / NPS / NP / NQ series trucks equipped with 4HF1 / 4HE1 / 4HG1T diesel engines. This steering pump is the core power source of the hydraulic power steering system, converting the engine's mechanical energy into hydraulic energy to deliver stable, continuous hydraulic assistance to the steering gear — ensuring light and precise steering operation even at low speeds and under heavy loads.
The power steering pump is driven by the engine via a belt. It draws steering fluid (ATF or dedicated power steering fluid) from the reservoir, pressurizes it, and delivers it to the steering gear (or steering box). When the driver turns the steering wheel, the steering gear uses the hydraulic pressure to push the steering arm (or rack), turning the wheels.
This pump employs a vane-type hydraulic pump design: the rotor and cam ring are eccentrically arranged, and the vanes — under centrifugal force and hydraulic pressure — press against the cam ring inner surface, creating cyclic changes in sealed volume for oil suction and delivery. The pump incorporates an internal flow control valve and a safety valve (relief valve), ensuring a stable controlled flow (8.0 L/min) across varying engine speeds and automatically relieving pressure when the system exceeds 100 bar, protecting the entire hydraulic assist system from overload damage.
Replace the power steering pump when any of these symptoms appear:
- Heavy or stiff steering — internal pump wear causes insufficient output pressure and flow, most noticeable at low speeds or idle.
- Whining or hissing noise during steering — worn internal bearings, sticking vanes, or air ingress in the system increase operating noise.
- Steering fluid leakage — aged pump seals (oil seals, O-rings) allow fluid to seep from the pump shaft or housing joints.
- Steering wheel vibration or pulsation — a faulty flow control valve or internal pressure fluctuations cause uneven steering feel.
- Darkened steering fluid or metal debris — severe internal pump wear contaminates the hydraulic system with metal particles, potentially damaging the steering gear further.
- Complete loss of assist — a broken pump shaft or seized internal mechanism eliminates hydraulic assistance, making steering extremely heavy.
⚠️ Critical Inspection Note: Before replacing the steering pump, the steering system must be thoroughly flushed, the fluid in the reservoir replaced, and all lines and fittings checked for cleanliness. Never reuse old steering fluid. After installing the new pump, bleed the system (turn the steering wheel lock-to-lock several times at idle) and check fluid level and for leaks. Always inspect the drive belt tension and wear and replace if necessary.
| Verification Item | Data / Standard | Source / Method |
|---|---|---|
| Part Number (Short) | 8-97136574-0 | eBay, HUSUZO, multilingual product pages |
| Part Number (Long) | 8971365740 | HUSUZO, multilingual product pages |
| Official Part Name | PUMP ASM; OIL,P/S | HUSUZO product page |
| Vehicle Models | ISUZU NPR / NQR / NPS / NP / NQ | FridayParts, multilingual product pages |
| Engine Compatibility | 4HF1 / 4HE1 / 4HG1T | FridayParts, multilingual product pages |
| Pump Type | Vane-Type Hydraulic Pump | Product specification |
| Nominal Displacement | 7.0 ml/r | JAR Parts specification |
| Maximum Pressure | 100 bar | JAR Parts specification |
| Controlled Flow Rate | 8.0 L/min | JAR Parts specification |
| Speed Range | 500 – 5000 r/min | JAR Parts specification |
| Inlet Port Size | 17.5 mm | JAR Parts specification |
| Outlet Thread | M12 × 1.25 | JAR Parts specification |
| Rotation Direction | Left-Hand | JAR Parts specification |
| Net Weight | Approx. 2.4 – 5.1 kg | isuzu-truckspares, Persian product page |
| H/S Code | 841360100 | isuzu-truckspares specification |
| Certification | ISO9001 / TS16949 | isuzu-truckspares specification |
| Warranty | 12 Months | FridayParts, isuzu-truckspares |
| Cross-Reference OEM | 8-97136574-1 / 8971365741 | FridayParts |
| Cross-Reference OEM | 8-97115135-0 / 8971151350 | HUSUZO |
| Cross-Reference OEM | 8970851282 / 8-97085128-2 | FridayParts |
| Cross-Reference OEM | 8973886510 / 8973886511 | eBay, Everychina |
| Cross-Reference OEM | 8973572130 / 8973572131 | eBay, Everychina |
| Cross-Reference OEM | 8971365730 | Everychina |
| Cross-Reference OEM | 8-98006793-4 / 8980067934 | isuzu-truckspares |
| Brand | Model | Chassis | Engine | Years |
|---|---|---|---|---|
| ISUZU | ELF | NKR66 / NKR71 | 4HF1 / 4HG1 | 1994–2002 |
| ISUZU | NPR | NPR66 / NPR70 / NPR71 | 4HF1 / 4HE1 | 1990s–2000s |
| ISUZU | NQR | NQR70 / NQR71 / NQR75 | 4HF1 / 4HE1 / 4HG1T | 1996–2000s |
| ISUZU | NPS | NPS66 / NPS71 | 4HF1 | 1990s–2000s |
| ISUZU | NP / NQ | — | 4HF1 / 4HE1 | — |
| Engine Model | Displacement | Common Applications |
|---|---|---|
| 4HF1 | 4.3L | NPR66, NQR70, NKR66, NPS66 |
| 4HE1 | 4.8L | NPR70, NQR70, NQR75 |
| 4HG1T | 4.6L Turbo | NQR71, NKR71 |
⚠️ Important Fitment Notes:
- This steering pump is designed for the 4HF1 / 4HE1 / 4HG1T engine family. Confirm your specific engine model and year before ordering.
- The 8-97136574-0 is the primary OEM number. The 8-97136574-1, 8-97115135-0, 8970851282, 8973886510, 8973572130, 8971365730, and 8-98006793-4 are cross-reference numbers for the same application. Verify your exact OEM number against your original component.
- Before replacing the steering pump, the steering system must be thoroughly flushed, the fluid in the reservoir replaced, and all lines and fittings checked for cleanliness. Never reuse old steering fluid.
- After installing the new pump, bleed the system (turn the steering wheel lock-to-lock several times at idle) and check fluid level and for leaks.
- Always inspect the drive belt tension and wear and replace if necessary.
- For right-hand drive (RHD) vehicles, verify line routing. Refer to the ISUZU workshop manual for the correct procedure.
📌 Fitment Verification: To ensure 100% accurate matching, please provide the VIN or chassis number before ordering. We will verify it through the ISUZU global EPC system.
| Feature | Benefit + Verification Signal |
|---|---|
| Vane-Type Hydraulic Pump Design | Compact, smooth-running design delivering stable hydraulic assistance across a wide speed range — verified by JAR Parts specification. |
| 7.0 ml/r Displacement / 8.0 L/min Controlled Flow | Precision-matched to the 4HF1/4HE1 steering system flow requirements for responsive steering and linear feel — verified by JAR Parts specification. |
| 100 bar Maximum Pressure | Delivers sufficient hydraulic assistance under heavy loads and low speeds for light steering effort — verified by JAR Parts specification. |
| Integrated Flow Control Valve & Safety Valve | Automatically regulates output flow and prevents system overpressure, protecting the steering gear, lines, and seals — verified by product specification. |
| 500–5000 r/min Wide Speed Range | Adapts to the full diesel engine operating range from idle to high speed with stable assist output — verified by JAR Parts specification. |
| Cast Iron Housing (some configurations) | High structural strength, pressure resistance, and excellent heat dissipation — verified by Persian product page "Cast Iron" specification. |
| ISO9001 / TS16949 Certified | Controlled manufacturing process with full traceability — verified by isuzu-truckspares certification information. |
| 12-Month Warranty | Manufacturer-backed one-year warranty for fleet and commercial operations — verified by FridayParts and isuzu-truckspares. |
| QC Item | Verification Method / Standard |
|---|---|
| Pump Housing Mounting Holes | CMM, 100% inspection |
| Shaft Diameter & Spline | CMM, 100% inspection |
| Inlet / Outlet Port Dimensions | CMM / thread gauge, 100% inspection |
| Flow Characteristics (8.0 L/min) | Flow test bench, 100% inspection |
| Pressure Characteristics (100 bar) | Pressure test bench, 100% inspection |
| Relief Valve Opening Pressure | Pressure test bench, 100% inspection |
| Internal Leakage | Leakage test, 100% inspection |
| Rotation Flexibility | Functional test, 100% inspection |
| Noise Test | Noise tester, 100% inspection |
| Material Hardness | Rockwell hardness tester, batch sampling |
| Surface Finish | Visual inspection — no cracks, no porosity, no corrosion |
| Batch Traceability | Material lot number + production date |
| Packaging Protection | Anti-rust oil + VCI film + carton |
⚠️ IMPORTANT: Steering system service must be performed by a qualified technician. Before replacing the steering pump, drain the old fluid and thoroughly flush the system. Never reuse old steering fluid. The system must be thoroughly bled after installation.
- Preparation: Disconnect the battery negative terminal. Place a drain pan under the steering pump. Remove the drive belt.
- Removal: Disconnect the inlet and outlet lines from the steering pump. Remove the pump mounting bolts and withdraw the old pump.
- Inspection: Inspect the mounting bracket for cracks or deformation. Check the lines and fittings for damage or blockage. Inspect the drive belt for wear.
- Installation: Install the new pump onto the bracket and torque the mounting bolts to specification. Connect the inlet and outlet lines.
- Filling & Bleeding: Fill the reservoir with the specified new steering fluid. With the engine at idle, turn the steering wheel lock-to-lock several times to bleed air from the system. Check and top up the fluid level.
- Leak Check: Inspect all fittings, the pump body, and lines for leaks.
- Road Test: Perform a road test to verify proper steering assist, absence of abnormal noise, and no leaks.
| Fastener | Torque |
|---|---|
| Steering Pump Mounting Bolts | Per ISUZU workshop manual specification |
| Outlet Line Fitting (M12×1.25) | Per ISUZU workshop manual specification |
| Inlet Line Clamp | Per ISUZU workshop manual specification |
- Every 10,000 km: Check steering fluid level and condition. Inspect the pump and lines for leaks.
- Every 40,000–50,000 km: Inspect drive belt tension and wear. Check the pump for abnormal noise during operation.
- Every 2 years: Replace the steering fluid and thoroughly flush the system.
- When steering feels heavy or abnormal noise is detected: Inspect pump pressure, flow, and system sealing immediately.
- Standard Packaging: Anti-rust oil + VCI film + neutral carton.
- Custom Packaging: Neutral box, color box, or customer-branded packaging.
- Suitable For: Steering system repair shops, ISUZU parts distributors, fleet maintenance centers.
- Supply Capacity: Stable batch supply with batch-level quality reports available.
- MOQ: 1 PCS
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