ISUZU NKR NPR Sub Spring Rubber 8972543870 OEM Fit

The Sub Spring Rubber with OEM numbers 8972543870 and 8-97254387-0 is a verified direct-fit replacement for ISUZU NKR / NPR / NQR series light and medium-duty trucks equipped with 4JB1 / 4HK1 / 4JJ1 / 4BD1 diesel engines. This rubber buffer is installed between the helper spring (sub spring) and the main spring or bracket. It cushions the impact of the helper spring under heavy loads, isolates vibration, prevents direct metal-to-metal contact and wear, and maintains the helper spring's preload state to ensure a smooth transition between unladen and fully laden conditions.

The sub spring rubber is an elastic limit and buffer element in the leaf spring suspension system. When the vehicle is unladen or lightly loaded, the helper spring does not contact the main spring, and the rubber buffer remains free or slightly compressed. As the load increases and the main spring deflects to a certain point, the helper spring begins to carry load, and the rubber buffer is compressed between the main and helper springs, absorbing impact energy and preventing hard metal-to-metal collision between the helper spring and the main spring or bracket.

The 8972543870 is manufactured from high-quality natural rubber with an embedded 4.5 mm steel insert as a reinforcement layer. This ensures the buffer does not tear or detach under long-term high-frequency compression and shear loads while maintaining stable elastic recovery. Compared to ordinary market parts, this product offers a longer service life and higher cost-effectiveness.

Replace the sub spring rubber when any of these symptoms appear:

• Metallic knocking or "clunking" noise from the rear suspension under heavy load — the rubber buffer is worn, flattened, or missing, causing direct metal contact between the helper spring and the main spring or bracket.
• Increased vibration or reduced ride comfort — the rubber has aged and lost elasticity, failing to effectively absorb helper spring impacts.
• Helper spring misalignment or abnormal noise — reduced buffer thickness or deformation causes unstable helper spring positioning under load.
• Visible cracks, tears, permanent deformation, or exposed steel insert — the rubber has failed or the steel insert has separated, requiring replacement.
• Abnormal wear or corrosion at the helper spring-to-main spring contact surface — metal-to-metal friction due to missing rubber isolation.

1. Preparation: Raise and support the rear axle, relieve leaf spring tension. Clean the helper spring and main spring/bracket contact surfaces.
2. Removal: Remove the U-bolts or bracket securing the helper spring and extract the old rubber buffer.
3. Inspection: Inspect the helper spring and main spring for cracks, deformation, or severe corrosion. Check the bracket for wear.
4. Installation: Position the new rubber buffer correctly between the helper spring and main spring/bracket. Verify no skewing.
5. Reassembly: Install the U-bolts or bracket and torque to specification.
6. Final Check: Verify the buffer is correctly seated and not extruded. Lower the vehicle.
7. Road Test: Perform a road test to confirm no abnormal noise under heavy load and proper suspension cushioning.

• Every 10,000 km: Inspect sub spring rubber for cracks, permanent deformation, or exposed steel.
• Every 40,000–50,000 km: Check buffer thickness and elasticity; replace if aged or flattened.
• At every rear suspension service: Always inspect the sub spring rubber and replace if any abnormality is found.

• Standard Packaging: Sealed bag + moisture barrier + neutral carton.
• Custom Packaging: Neutral box, color box, or customer-branded packaging.
• Suitable For: Suspension system repair shops, ISUZU parts distributors, fleet maintenance centers.
• Supply Capacity: Stable batch supply with batch-level quality reports available.
• MOQ: Small quantities accepted (quantity discounts available).