Brake Booster / Master Vac Assembly 8973015350 8-97301535-0 For ISUZU D-MAX 2002–2003 TFR TFS 4JA1 — OEM-Spec Aftermarket, 24.5×24.5×24cm, 6-Month Warranty

The Brake Booster / Master Vac Assembly with OEM references 8973015350 / 8-97301535-0 is a verified replacement brake assist component for the ISUZU D-MAX (TFR/TFS) pickup, specifically the 2002–2003 model years equipped with the 4JA1 (2.5L diesel) engine. Cataloged under the ISUZU factory description "MASTER VAC ASM;BRK" (Master Vacuum Assembly; Brake), it is the vacuum brake booster that amplifies driver pedal force to reduce braking effort and shorten stopping distance.

The brake booster is the vacuum-assisted servo unit mounted between the brake pedal and the master cylinder. It uses engine vacuum (or vacuum pump supply on diesel engines) to create a pressure differential across an internal diaphragm, multiplying the force applied to the master cylinder piston. Without a functioning booster, pedal effort becomes extremely high and braking distances increase dramatically — a critical safety concern for a loaded commercial pickup.

This unit is supplied as an OEM-specification aftermarket component under the YIMI / CHINA AFTERMARKET brand designation, with a reference actual size of 24.5 × 24.5 × 24 cm (packaging size 25 × 24.5 × 24 cm) and a 6-month quality guarantee. It is widely cross-referenced in the aftermarket, including the DLJ Auto Parts reference 8-97301-535-0 (listed for D-MAX TFR/TFS 05-) and the Italur reference 8-97301535-0-IM (listed for Chevrolet D-MAX).

• OEM Description & Product Type Verified: "MASTER VAC ASM;BRK" — confirmed by Japanese, German, Dutch, and Russian supplier factory data for 8973015350 / 8-97301535-0.
• Vehicle & Engine Coverage Verified: ISUZU D-MAX 2002–2003, engine 4JA1 — confirmed across YIMI/Ecer portals and independent supplier listings.
• Dimensions Verified: Actual size 24.5 × 24.5 × 24 cm; packaging size 25 × 24.5 × 24 cm — confirmed by YIMI/Ecer factory data.
• Warranty & MOQ Verified: 6-month quality guarantee; MOQ 10 PCS; supply capacity 10,000 pcs/month — confirmed by YIMI/Ecer supplier data.
• Cross-Reference Density Verified: 8973015350, 8-97301535-0, 8-97301-535-0, 8-97301535-0-IM, WW-DX0038, F01G0610FJ are consistently grouped as interchangeable/related references across DLJ Auto Parts, Italur, Ecer, and additional international catalogs.
• Brand Reference Verified: YIMI / CHINA AFTERMARKET — confirmed as the supplier brand for this booster family.

• Hard brake pedal / excessive pedal effort: The most common symptom. The booster no longer amplifies pedal force, requiring heavy stomping to stop the vehicle — especially noticeable at low engine speeds or during repeated braking.
• Hissing or air-leak noise from the booster area: A ruptured diaphragm or failed check valve allows vacuum to escape, producing a persistent hissing or "fsss" sound from the engine bay or under the dashboard.
• Longer stopping distance / delayed brake response: Insufficient vacuum assist means the brakes engage later and with less force, extending stopping distances — a critical safety concern for a loaded D-MAX pickup.
• Brake pedal does not return quickly: A booster with internal valve damage can prevent the pedal from returning promptly, affecting drivability and safety.
• Intermittent power assist loss: Vacuum leaks can cause the assist to fade after the first pedal application, requiring repeated pumping to maintain braking force.
• Rough idle or engine stumble when braking: A failed booster diaphragm can allow unmetered air to enter the intake manifold, disrupting idle quality on the 4JA1 diesel.

• Model year window is the first check: This booster is confirmed for 2002–2003 D-MAX in multiple factory catalogs. DLJ lists a related reference for 05- D-MAX, but production changes across the D-MAX platform may affect vacuum port location, sensor provision, or mounting bracket geometry. Provide the VIN for final confirmation.
• Sensor provision must be confirmed: Some D-MAX boosters carry a brake pedal or vacuum sensor. This standard aftermarket unit does not explicitly include a sensor provision. If the original booster has a sensor connector, confirm sensor compatibility before ordering — a missing sensor circuit will trigger a warning light and may affect brake assist logic.
• Cross-brand Chevrolet coverage: The 8-97301535-0-IM reference confirms this booster family also serves Chevrolet D-MAX applications. This makes it a cross-brand SKU for distributors serving both ISUZU and Chevrolet pickup populations.
• Cross-reference caution with F01G0610FJ: DLJ lists F01G0610FJ for D-MAX TFR/TFS 08-12 — this is a different year window from the 2002–2003 application of 8973015350. Do not assume interchangeability across the 2003/2005/2008 year boundaries without physical comparison.

1. 1Confirm the required part first: Verify that the original booster is the vacuum type and matches the 2002–2003 D-MAX / 4JA1 application. Check whether the original unit has a sensor provision that the replacement must match.
2. 2Safety first: Park on level ground, engage the parking brake, and chock the rear wheels. Disconnect the battery negative terminal.
3. 3Disconnect the vacuum source and check valve: Remove the vacuum hose from the booster check valve. Note the orientation for reassembly.
4. 4Disconnect the master cylinder: Unbolt the master cylinder from the booster. Support the master cylinder to avoid stressing the brake lines. Plug the lines if fully removed.
5. 5Remove the clevis pin from the brake pedal: From inside the cabin, remove the clevis pin connecting the booster pushrod to the brake pedal arm.
6. 6Remove the booster mounting bolts: From the engine bay, unbolt the booster from the firewall or pedal bracket. Extract the booster carefully.
7. 7Transfer components: If the original booster carries a check valve, gasket, or boot that is not included with the replacement, transfer it to the new unit. If a sensor is present on the original, confirm whether it can be transferred or must be ordered separately.
8. 8Install the new booster: Position the 8973015350 booster onto the firewall. Install the mounting bolts and torque to specification.
9. 9Reconnect the pushrod and master cylinder: Reconnect the clevis pin to the brake pedal. Reattach the master cylinder to the booster and torque the mounting nuts to specification.
10. 10Reconnect the vacuum hose and check valve: Ensure the check valve is oriented correctly and the hose is fully seated.
11. 11Bleed the brake system (if hydraulic lines were opened): Bleed the brakes according to the ISUZU procedure until clear, bubble-free fluid flows.
12. 12Test operation: With the engine running, depress the brake pedal and verify that assist is present (pedal should be noticeably easier to press than with the engine off). Check for hissing noises that would indicate a vacuum leak. Road-test at low speed before returning the vehicle to service.

• Inspect the booster vacuum hose and check valve at every brake service or every 20,000–30,000 km — a cracked hose or stuck check valve can mimic booster failure.
• Check for pedal feel changes during routine driving — a progressively hardening pedal indicates declining booster performance.
• Replace the booster at the first sign of hissing, hard pedal, or delayed assist — do not "monitor" a known-failing safety component on a commercial pickup.
• Confirm the sensor provision if replacing a sensor-equipped original booster — a missing sensor circuit will trigger a warning light and may affect brake assist logic.

• Standard packing: Neutral packaging or customer-requested packaging. Packaging size reference: 25 × 24.5 × 24 cm.
• Package contents: 1 × Brake Booster / Master Vac Assembly. Master cylinder, check valve, vacuum hose, sensor (if applicable), and mounting hardware are not included unless explicitly stated — confirm exact package contents at inquiry.
• Set options: Booster only (standard) / booster + check valve kit (subject to availability) — specify at inquiry.
• Suitable for: ISUZU D-MAX brake system repair shops, light commercial fleet maintenance departments, Chevrolet D-MAX service providers, spare parts distributors, and export wholesalers serving Southeast Asia, the Middle East, Africa, and Latin America.
• Related parts available: Brake master cylinder (8-97301-532-0 reference for D-MAX 2002–2012), vacuum check valve, vacuum hose, brake fluid, and complete D-MAX brake system service kits.