SACHSVALEOWABCOZF CLUTCHSINOTRUK Clutch Cover & Disc Common Faults & Professional Repair TipsPart 1: Common Typical Faults of HOWO Clutch Pressure Plate & Clutch Disc1. Clutch Vibration & Jitter When Starting Off Phenomenon: Obvious shaking of cab when starting under load, especially when carrying heavy cargo. Trigger Causes: Friction surface of clutch disc glazed, cracked or partial wear after long-term heavy load; Uneven spring pressure of pressure plate diaphragm spring, individual spring fatigue failure; Deformed clutch pressure plate friction surface; Loose flywheel fixing bolts or flywheel surface warpage. 2. Clutch Slippage (Power Loss, High Exhaust Temperature) Phenomenon: Engine revs rise sharply while vehicle speed increases slowly, burning smell from clutch, climbing inability with full load. Trigger Causes: Over-worn clutch disc friction lining, rivets exposed; Diaphragm spring of pressure plate loses elasticity, insufficient clamping force; Oil leakage from crankshaft rear oil seal / transmission input shaft oil seal contaminates friction plate; Improper free travel of release bearing (too small). 3. Difficult Gear Shifting & Gear Grinding Noise Phenomenon: Hard to engage gears, obvious grinding sound when shifting; clutch pedal pressed to bottom but power not completely cut off. Trigger Causes: Release bearing stuck or damaged; Diaphragm spring fingers uneven wear, incomplete separation of pressure plate; Clutch disc hub splines rusted & stuck on transmission input shaft; Excessive free travel of clutch pedal. 4. Abnormal Noise From Clutch Assembly Noise when stepping on clutch pedal: Damaged release bearing, dry lubrication; Noise when releasing clutch: Broken disc damping springs, loose disc rivets; Metallic friction noise during driving: Exposed rivets scraping pressure plate / flywheel. 5. Clutch Pedal Too Soft / Too Hard Soft pedal: Partial fracture of diaphragm spring, air inside hydraulic clutch pipeline; Stiff pedal: Rust & deformation of diaphragm spring fingers, stuck release fork. Part 2: Step-by-Step Repair & Troubleshooting Solutions
Fault 1: Starting Vibration & Jitter Repair
Dismount gearbox, take out clutch assembly; inspect flywheel surface first. Grind flat if warped, replace flywheel when deformation exceeds 0.2mm.
Check pressure plate diaphragm springs one by one: Replace whole pressure plate if any spring fatigues, cracks or height difference over 1.5mm.
Replace worn, glazed clutch disc; choose high-friction non-asbestos clutch disc matching SINOTRUK models.
Clean oil stain on flywheel and pressure plate completely; repair leaking crankshaft rear oil seal at the same time if oil contamination exists.
After installation, adjust clutch release bearing free travel to standard 3–5mm; test drive after finishing four-wheel alignment.
Fault 2: Clutch Slippage Repair
Check for oil leakage of engine rear oil seal and transmission front oil seal first; replace FKM high-temperature oil seal to avoid repeated oil seepage.
Measure friction lining thickness of clutch disc: Replace disc when residual thickness less than 3mm.
Test clamping force of pressure plate diaphragm spring; replace pressure plate if elasticity declines.
Adjust clutch pedal free travel to standard value to ensure full clamping of pressure plate.
Remind customer to avoid long-time half-clutch operation when climbing or overloading to extend service life.
Fault 3: Difficult Gear Shift & Grinding Noise Repair
Replace failed release bearing and fill high-temperature lithium grease during installation.
Trim uneven worn diaphragm spring fingers or directly install new pressure plate.
Polish rusted input shaft splines, apply anti-seize grease; replace clutch disc if hub splines severely worn.
Adjust clutch pedal free travel to eliminate incomplete separation failure.
Fault 4: Clutch Abnormal Noise Repair
Noise on pressing pedal: Directly replace release bearing, inspect release fork for deformation.
Noise on releasing pedal: Replace clutch disc with broken damping springs; avoid single-side replacement, match pressure plate and disc as a set.
MMetallic scraping sound: Immediately replace clutch disc to prevent rivets scratching flywheel (high cost of flywheel repair).
Fault 5: Clutch Pedal Too Soft / Hard Repair
Soft pedal: Bleed air from clutch master/slave cylinder hydraulic pipeline; replace broken diaphragm spring; inspect master cylinder for internal leakage.
Stiff pedal: Clean & lubricate release fork and spring fingers; replace rusted & deformed pressure plate assembly.
Part 3: Maintenance & Installation Key Notes (For Overseas Repair Shop Customers)
It is recommended to adopt complete clutch kits (pressure plate + clutch disc + release bearing) for replacement, separate replacement easily causes mismatching and repeated failure.
Our products are compatible with SACHS, ZF, VALEO, EATON standard dimensions, interchangeable for heavy-duty trucks.
After each clutch overhaul, oil seals of engine and gearbox must be inspected synchronously; FKM skeleton oil seals effectively resist high temperature and salt corrosion for tropical overseas markets.
Strictly prohibit overloading and long half-clutch driving, which are the main causes of rapid clutch wear for all trucksPremium Clutch Replacement Parts | SINOTRUK Clutch Service Guide
We supply full clutch kits including pressure plate, clutch disc and release bearing compatible with SACHS, ZF, VALEO, EATON standards.
Above professional fault diagnosis and step-by-step repair skills help overseas repair workshops solve common clutch jitter, slipping, hard shifting and abnormal noise problems, reducing vehicle downtime and rework rate. All spare parts adopt wear-resistant friction material and high-elastic diaphragm spring, ideal for heavy-duty HOWO light dump trucks.
