Steel Construction Alternator Vacuum Pump Oil Pipe with Banjo Fittings for ISUZU 4HG1 Engine ISO 9001 Certified
The alternator vacuum pump oil pipe carrying OEM numbers 8972286700 and 8-97228670-0 is a rigid or semi‑rigid lubrication line that supplies engine oil to the vacuum pump mounted on the back of the alternator on ISUZU 4HG1 diesel engines. It is a direct replacement for the original factory pipe used in NPR, NKR, and NQR series medium‑duty trucks from the late 1980s through the early 2000s.
The 4HG1 is a 4,334 cc inline‑four naturally aspirated diesel engine producing 88–96 kW (120–130 PS). Unlike gasoline engines, this diesel has no intake manifold vacuum, so a dedicated engine‑driven vacuum pump is required to generate vacuum for the brake booster (vacuum servo). On the 4HG1 – as on many ISUZU engines of that era – the vacuum pump is integrated with the alternator, mounted directly to its rear housing. The pump's internal rotor and vanes require a continuous supply of engine oil for lubrication and cooling. This oil pipe carries pressurised oil from the engine block (typically from an oil gallery port near the oil filter housing or main oil galley) to the vacuum pump inlet.
The pipe is made of steel tubing with formed ends and flared or banjo‑type fittings. It operates at engine oil pressure (typically 2–5 bar / 30–75 psi) and at temperatures up to 120°C. Over time, the original pipe may develop pinhole leaks from corrosion (especially in road‑salt regions), crack from vibration fatigue, or become clogged with sludge if oil changes were neglected. A failed oil pipe will starve the vacuum pump of lubrication, leading to pump seizure, loss of brake assist (hard pedal), and potential alternator damage. This replacement pipe restores proper oil flow and protects the vacuum pump from premature failure.
This ISUZU 4HG1 vacuum pump oil pipe directly replaces the factory pipe in the following configurations:
| Chassis | Engine | Years | Notes |
|---|---|---|---|
| ISUZU NPR66 | 4HG1 | 1987–1994 | Most common 4HG1 application |
| ISUZU NKR66 | 4HG1 | 1987–1994 | Light cab‑over |
| ISUZU NKR69 | 4HG1 | 1994–2002 | Late NKR chassis |
| ISUZU NPR69 | 4HG1 | 1994–2002 | Heavy‑duty chassis |
| ISUZU NQR71 | 4HG1 | 1994–2002 | Medium chassis |
| ISUZU 100P / 600P (selected) | 4HG1 | 1990–2000 | Some export variants |
| Chevrolet / GMC W‑series (rebadged) | 4HG1 | 1990–2000 | North American market |
The pipe is also compatible with the 4HF1 engine (predecessor of the 4HG1) that uses the same alternator‑mounted vacuum pump design. However, always verify the original pipe routing before ordering, as some 4HF1 applications use a different bend profile.
Each batch of the ISUZU alternator vacuum pump oil pipe undergoes the following quality control procedures:
| QC Item | Verification Method |
|---|---|
| Tube material | Certificate of analysis – steel grade (e.g., ST37 or equivalent) |
| Bend angle accuracy | Optical comparator or gauge fixture – within ±2 degrees of OE drawing |
| Overall length | Digital caliper measurement – ±1.5 mm tolerance |
| Fitting thread profile | Go/No‑go gauge for banjo bolt threads (M12*1.25 or M14*1.5) |
| Sealing washer seat | Visual inspection – no burrs or deformation on banjo face |
| Pressure test (batch sample) | Sample pipe pressurised to 10 bar for 30 seconds – no pressure drop |
| Coating thickness | Magnetic induction meter (for zinc coating) – minimum 5 microns |
| Visual inspection | 100% – no kinks, cracks, rust, or damaged fittings |
The facility holds ISO 9001:2015 certification. A certificate of conformance (COC) with batch traceability is available for wholesale orders. For first‑time buyers, a pre‑shipment inspection report with pipe dimensions can be provided for a sample order.
- Individual packaging: Sealed in anti‑rust VCI bag, placed in foam‑lined carton or poly bag
- Carton dimensions: 30 * 10 * 5 cm per unit
- Net weight: 0.10–0.15 kg; gross weight (with packaging): 0.20 kg
- Master carton: 200 units per export carton (approx. 45 * 35 * 25 cm, 18 kg)
- Lead time: 3–7 working days for stock orders; 15–20 days for production orders above 500 pieces
- Minimum order quantity: 1 piece (sample order available)
- Shipping methods: FedEx, UPS, DHL for samples; sea freight (LCL/FCL) from Shanghai, Ningbo, Guangzhou ports
- H/S Code: 8409.99 (engine parts)
For workshops performing a full vacuum pump service, the supplier also stocks rebuilt or new alternator‑mounted vacuum pumps for the 4HG1, as well as replacement banjo sealing washers (copper or aluminum). Contact the sales team with your forecasted monthly volume and destination port for a tiered price list.
The ISUZU 4HG1 alternator vacuum pump oil pipe 8972286700 is a direct‑fit steel lubrication line that carries engine oil to the vacuum pump on NPR, NKR, and NQR trucks. It prevents pump seizure, maintains brake assist, and protects the alternator. One part number covers multiple chassis, installs with basic tools, and is ISO 9001 certified. Order a sample today to restore proper oil flow to your 4HG1's vacuum pump.
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