Clutch Disc 1878 007 046 Product Knowledge

OE Part No.: 1878 007 046;Alternative OEM Numbers: 21615194, 85013334, 7421639503. It is a 430 mm heavy‑duty clutch disc with torsional damper for European heavy‑duty trucks, SACHS 430WGTZ.

1. Core Technical Parameters

Application: Volvo FH12 / FM12 / FMX; Renault C/D/K/T series heavy‑duty trucks, compatible with AMT and manual transmissions.

2. Component Structure

Clutch Disc Steel Plate (Driven Plate)

Material: High‑carbon alloy spring steel plate, stamped, quenched and tempered. Strict control on flatness and end‑face run‑out. Resistant to thermal deformation to avoid high‑speed vibration and judder on take‑off.

Function: Connect friction facings and damper hub, transmit torque and allow minor axial elastic deformation.

Failure symptoms: Warped or wavy steel plate, rivet hole tearing. Consequences include clutch judder, incomplete disengagement.

Friction Facings (Aramid / Semi‑organic Asbestos‑Free Facing)

Double‑sided friction facings riveted to both sides of steel plate. High temperature resistance and anti‑burn performance for heavy‑duty conditions with frequent half‑clutch operation and uphill heavy loads.

Torsional Vibration Damper Assembly (Core Component)

Multiple sets of high‑stiffness damper springs and damping friction washers. Absorb engine torsional vibration, reduce gear‑shift shock and transmission noise, suitable for high‑torque diesel engines.

Fatigue or broken springs will cause idle‑speed vibration and impact noise during acceleration.

Spline Hub

24‑tooth internal spline to mate with gearbox input shaft. Worn splines with excessive clearance lead to gear‑shift impact and noise.

3. Material Highlights

Driven steel plate: Spring alloy steel. Heat‑treated for balanced strength and toughness, resistant to thermal warping. Steel plate deformation is irreversible. Replace directly once warped; straightening for reuse is prohibited.

Damper springs: Silicon‑manganese spring steel. Resistant to high‑temperature relaxation, maintains spring force under heavy‑load alternating impact.

Friction facings: Asbestos‑free aramid composite material with stable friction coefficient and high heat resistance. Must avoid oil contamination. Oil‑soaked facings result in slipping and burnt facings.

4. Typical Failure Modes

Excessive facing wear: Rivet heads exposed, slipping and power loss. Replace when rivet depth approaches facing surface.

Warped / wavy steel plate: Caused by overheating from prolonged half‑clutch. Symptoms: take‑off judder, incomplete disengagement, gear‑grinding when shifting.

Broken / loose damper springs: Knocking impact noise at idle or under acceleration.

Worn spline hub: Excessive clearance with input shaft, gear‑shift impact.

Burnt & carbonized facings: High temperature from continuous slipping, facings turn black and hard with reduced friction coefficient.

Repair Note: Discard directly if steel plate shows distortion, cracks or elongated rivet holes. Reuse after straightening is strictly forbidden.

5. Installation & Service Key Points

When replacing this clutch disc, inspect flywheel and pressure plate surface simultaneously. Re‑surface or replace if flywheel groove depth＞0.5 mm or pressure plate warps. Premature failure will occur if only the disc is replaced.

Check pilot bearing (input shaft pilot sleeve). Sticking pilot bearing causes incomplete clutch disengagement.

Apply a small amount of special spline grease on splines before installation. Keep grease completely away from friction facings.

Tighten bolts diagonally and evenly to ensure coaxiality and prevent high‑speed vibration.

After installation, adjust clutch pedal free travel and bleed air from slave & master cylinder.

6. Sourcing & Part Identification (After‑market & Foreign Trade)

Genuine SACHS part: Stamped marking and part number 1878 007 046 on steel plate, complete damper springs and damping washers.

For aftermarket alternatives, verify key dimensions: 430 mm outer diameter, 24‑tooth spline, 64 mm hub height, torque capacity ≥2600 N·m. Wrong spline or hub height leads to assembly failure.

QC inspection items: Steel plate flatness, firm rivets, intact damper springs without looseness or fracture, no cracks or missing blocks on friction facings.

7. Selling Points for Foreign‑Trade Product Page

‑ 430 mm heavy‑duty clutch disc for Volvo & Renault heavy‑duty trucks, rated torque 2600 N·m, ultimate torque 3500 N·m. ‑ Heat‑resistant heat‑treated steel substrate, anti‑warp performance, tightly‑controlled end‑face run‑out. ‑ Multi‑set long‑travel torsional damper springs, effectively filter engine torsional vibration, lower gear‑shift shock and transmission noise. ‑ Aramid composite friction facings, excellent high‑temperature & anti‑burn performance, long service life under heavy‑load and uphill working conditions. ‑ Standard 24‑tooth spline hub, direct OE replacement for 1878007046, cross‑reference OE numbers: 21615194 / 85013334 / 7421639503.

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