ISUZU ELF 4HK1 Clutch Release Bearing 1-31310012-0 81TKL4801 OEM Fit

The release bearing is a thrust ball bearing or angular contact bearing. Its inner ring mates with the release bearing seat, while the outer ring (or face) contacts the diaphragm spring release fingers. When the clutch pedal is depressed, the release fork pushes the bearing forward along the transmission input shaft axis via the seat, and the bearing face presses against the high-speed rotating diaphragm spring fingers. Because the diaphragm spring rotates with the engine while the bearing outer ring (or face) experiences high-speed relative sliding at the moment of contact, the release bearing must offer high-speed capability, wear resistance, and heat resistance.

The 81TKL4801 series bearing is manufactured from bearing steel, packed with long-life grease, and fitted with seals at both ends to prevent grease leakage and dust ingress. The 4HK1 is a 5.2L inline-four diesel engine widely used in ISUZU NPR / NQR / ELF series trucks.

Replace the release bearing when any of these symptoms appear:

• "Humming," "grinding," or "squealing" noise when the clutch pedal is depressed — worn bearing races, degraded grease, or pitted balls; the most typical release bearing failure signal.
• Abnormal clutch pedal free play or a "binding" feel — bearing seizure or face wear prevents smooth transmission of fork travel.
• Incomplete clutch disengagement or difficulty engaging gears — a severely worn bearing face cannot press the diaphragm spring to the full release position.
• Noise when the pedal is depressed that disappears when released — the bearing produces noise when contacting the diaphragm spring and stops under load when released.
• Visible burning, discoloration, or severe wear on the bearing face — heat or dry friction damage requiring immediate replacement.
• Binding sensation or excessive axial play when rotating the bearing — internal structural damage with seizure risk.

1. Preparation: Disconnect the battery negative terminal. Raise the vehicle and support the transmission. Remove the driveshaft and transmission.
2. Removal: Remove the release bearing and bearing seat from the first-shaft bearing cover. Check the bearing for smooth rotation and noise.
3. Inspection: Inspect the bearing face for burning or wear. Check the release bearing seat guide surface, release fork, and ball stud. Inspect the transmission first-shaft bearing cover guide surface.
4. Installation: Apply high-temperature grease to the bearing inner ring and guide surface. Install the new bearing onto the release bearing seat, ensuring correct seating.
5. Transmission Reinstallation: Install the transmission and connect the driveshaft. Check and adjust the release fork clearance to approx. 3–4 mm.
6. Pedal Check: Verify clutch pedal free play meets specification.
7. Road Test: Start the engine and test gear engagement in all gears for smoothness, complete clutch disengagement, and absence of abnormal noise.

• Every 10,000 km: Note any clutch pedal noise; check pedal free play.
• Every 40,000–50,000 km: Check release bearing rotation smoothness; whenever the clutch kit is replaced, the bearing and seat must be inspected.
• At clutch kit replacement: Always inspect and replace the release bearing, bearing seat, release fork, and ball stud as necessary.
• When clutch pedal noise or hard shifting is detected: Inspect the release bearing and bearing seat immediately.

• Standard Packaging: Anti-rust oil + VCI film + neutral carton.
• Custom Packaging: Neutral box, color box, or customer-branded packaging.
• Suitable For: Clutch and transmission 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).