8970369290 OEM Fit Brake Vacuum Booster 8"+9" Tandem Dual-Diaphragm for ISUZU NPR 4HF1
| Booster Type: | Vacuum Tandem (Dual-Diaphragm) | Effective Size: | 8"+9" |
| Material: | Metal (Iron / Aluminium) | Diaphragm Material: | NBR (Nitrile Butadiene Rubber) |
| Engine Compatibility: | 4HF1 / 4JH1 / 4KH1 | Vehicle Models: | ISUZU NPR / NPR71 / NPR66 / 600P |
| OEM Part Number: | 8970369290 / 8-97036929-0 | Condition: | Brand New — 100% Quality Inspected |
| High Light: | 8970369290 OEM Fit Brake Vacuum Booster,8"+9" Tandem Brake Vacuum Booster,ISUZU NPR 4HF1 Brake Booster |
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The Brake Vacuum Booster with OEM numbers 8970369290 and 8-97036929-0 is a verified direct-fit replacement for ISUZU NPR / NPR71 / NPR66 / 600P series light and medium-duty trucks equipped with 4HF1 / 4JH1 / 4KH1 diesel engines. This booster utilises engine intake vacuum to create a pressure differential that amplifies the driver's brake pedal force, delivering light, linear braking output even under full-load conditions and effectively reducing driver fatigue on long hauls.
The brake vacuum booster is mounted between the brake master cylinder and the brake pedal. When the pedal is depressed, the control valve opens, allowing atmospheric pressure to enter one side of the booster chamber while engine vacuum acts on the other side. This pressure differential acts on the internal diaphragm, multiplying the pedal force by the boost ratio before transmitting it to the master cylinder piston, thereby achieving sufficient hydraulic pressure with reduced pedal effort. This unit employs an 8"+9" tandem dual-diaphragm design, providing a larger effective boost area than a single-diaphragm booster of the same diameter.
Replace the booster when any of these symptoms appear:
- Hard or stiff brake pedal — a failed booster cannot amplify pedal force, requiring significantly greater effort to stop the vehicle.
- Engine stalls or idles roughly when braking — a leaking booster diaphragm causes a vacuum leak that upsets the engine air-fuel mixture.
- Hissing noise from the brake pedal area — indicates diaphragm or control valve seal failure.
- Longer pedal travel or slow pedal return — internal mechanical failure prevents the pedal from returning properly.
- Vehicle pulling or insufficient braking force — a ruptured diaphragm causes uneven or lost boost assistance.
| Verification Item | Data / Standard | Source / Method |
|---|---|---|
| Part Number (Short) | 8970369290 | Japanese Isuzu-Truckspares; NAKOL product page |
| Part Number (Long) | 8-97036929-0 / 8-97036-929-0 | NAKOL product page; Persian Autopart-Masters |
| Part Name | Brake Vacuum Booster | Multilingual product pages (Japanese/German/Dutch/Indonesian) |
| Vehicle Models | ISUZU NPR / NPR71 / NPR66 / 600P | Guneybaglilar; NAKOL product page |
| Engine Compatibility | 4HF1 / 4JH1 / 4KH1 | NAKOL product page |
| Booster Size | 8"+9" Tandem (Double Diaphragm) | NAKOL product page |
| Material | Metal (Iron / Aluminium) | NAKOL product page |
| Brand | BZLP / NAKOL | Japanese Isuzu-Truckspares; NAKOL product page |
| Certification | ISO/TS 16949 | Third-party system audit |
| Warranty | 12 Months | NAKOL product page; Japanese Isuzu-Truckspares |
| MOQ | 10–50 PCS (varies by supplier) | Indonesian Isuzu-Truckspares; NAKOL product page |
| Packaging | Neutral Carton / Customer Brand | Multilingual product pages |
| Part Number | 8970369290 | Product Name | Brake Vacuum Booster |
| Car Model | NPR | Engine Model | 4HF1 |
| Condition | 100% Brand New | Size | Standard |
| Weight | Standard | Origin | China Mainland |
| Main Market | Middle East, Asia, Africa, South America, North America & Europe | Package | Neutral Packing Or Make It As Requested |
| Material | High-strength aluminum alloy & precision bearings | Cooling Type | Engine coolant circulation |
| Installation | Direct OEM replacement | Quality Standard | OEM equivalent / ISO quality control |
| Brand | Model | Chassis | Engine | Years |
|---|---|---|---|---|
| ISUZU | NPR | NPR | 4HF1 | 1990s–2000s |
| ISUZU | NPR71 | NPR71 | 4HF1 | 1990s–2000s |
| ISUZU | NPR66 | NPR66 | 4HF1 | 1990s–2000s |
| ISUZU | 600P | NKR | 4KH1 / 4JH1 | 1990s–2000s |
| Engine Model | Displacement | Common Applications |
|---|---|---|
| 4HF1 | 4.3L | NPR, NPR71, NPR66 |
| 4JH1 | 3.0L | 600P |
| 4KH1 | 3.0L | 600P |
- This booster is designed for ISUZU NPR / NPR71 / NPR66 / 600P series with 4HF1 / 4JH1 / 4KH1 engines. Confirm your specific model and year before ordering.
- The 8970369290 is the primary OEM number. The 8-97036929-0 / 8-97036-929-0 are alternative formats for the same part. Verify against your original component.
- Disconnect the battery negative terminal and relieve brake system pressure before installation.
- Never reuse old vacuum hoses or check valves.
- Thoroughly bleed the brake system after installation.
- For right-hand drive (RHD) vehicles, verify vacuum 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 |
|---|---|
| 8"+9" Tandem Diaphragm Design | Provides a larger effective boost area than a single-diaphragm booster of the same diameter for a lighter pedal feel — verified by NAKOL product page specification. |
| Precision-Stamped Steel Housing | Front and rear housings are precision-stamped from high-quality cold-rolled steel with refined welding, offering high structural strength and resistance to vacuum collapse or leakage — verified by NAKOL product description. |
| Oil-Resistant NBR Diaphragm | The core rubber diaphragm is made from nitrile butadiene rubber (NBR), offering excellent elasticity, anti-aging and anti-fatigue properties for stable sealing under long-term frequent use — verified by NAKOL product description. |
| Precision-Machined Push Rod & Piston | The push rod and piston assembly undergoes precision machining and surface treatment for smooth, jitter-free movement, with a boost ratio precisely matching the original vehicle design — verified by NAKOL product description. |
| Fast Response & Linear Braking Force | The booster delivers fast response and linear, stable brake force output — gentle braking with light pedal pressure and powerful stopping power with heavy pressure — verified by NAKOL product description. |
| Multi-Brand Availability (BZLP / NAKOL) | Multiple brand options to suit different markets and budgets — verified by multilingual product pages. |
| ISO/TS 16949 Certified | Full traceability with material certificates and batch inspection reports — third-party system audit. |
| QC Item | Verification Method / Standard |
|---|---|
| Housing Dimensions | CMM, 100% inspection |
| Diaphragm Dimensions & Appearance | CMM + visual, 100% inspection |
| Vacuum Tightness | Vacuum decay test, 100% inspection |
| Boost Ratio | Booster performance test bench, 100% inspection |
| Push Rod Travel & Return | Functional test, 100% inspection |
| Check Valve Function | Functional test, 100% inspection |
| Material Hardness | Rockwell hardness tester, batch sampling |
| Coating Thickness | Coating thickness gauge, batch sampling |
| Batch Traceability | Material lot number + production date |
| Packaging Protection | Anti-rust oil + VCI film + carton |
- Preparation: Disconnect the battery negative terminal. Drain the brake fluid reservoir. Disconnect the vacuum hose from the booster check valve.
- Removal: Remove the clevis pin connecting the brake pedal to the booster push rod from inside the cab. Remove the mounting nuts securing the booster to the firewall. Remove the master cylinder from the booster. Carefully withdraw the old booster.
- Inspection: Inspect the firewall mounting surface, brake pedal, and clevis for wear or damage. Check the vacuum hose and check valve for cracks or deterioration.
- Installation: Verify the new booster push rod length matches the original component. Install the new booster onto the firewall and torque the mounting nuts to specification. Install the master cylinder and torque the nuts to specification.
- Reconnection: Connect the brake pedal to the push rod with the clevis pin. Install a new check valve and vacuum hose. Fill with fresh DOT 3 or DOT 4 brake fluid.
- Bleeding: Bleed the brake system thoroughly to remove all air. Check for leaks at all connections.
- Pedal Test: Pump the brake pedal several times with the engine off to verify a firm pedal. Start the engine and verify the pedal drops slightly (indicating proper vacuum assist).
- Road Test: Perform a road test at low speed to verify proper braking performance.
| Fastener | Torque |
|---|---|
| Booster Mounting Nuts (Firewall) | Per ISUZU workshop manual specification |
| Master Cylinder-to-Booster Nuts | Per ISUZU workshop manual specification |
| Vacuum Hose Clamp | Per ISUZU workshop manual specification |
- Every 10,000 km: Check brake fluid level and condition. Inspect vacuum hose and check valve for cracks or leaks.
- Every 40,000–50,000 km: Inspect booster operation. Check for hissing noise or hard pedal.
- Every 2 years: Replace brake fluid regardless of mileage.
- When hard pedal or engine stall during braking is detected: Inspect booster, check valve, and vacuum hose immediately.
- When replacing the brake master cylinder: Always inspect booster push rod length and vacuum sealing.
- Standard Packaging: Anti-rust oil + VCI film + neutral carton.
- Custom Packaging: Neutral box, color box, or customer-branded packaging.
- Suitable For: Brake system repair shops, ISUZU parts distributors, fleet maintenance centers.
- Supply Capacity: Stable batch supply with batch-level quality reports available.
- MOQ: 10–50 PCS (varies by supplier).
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