Clutch Master Cylinder

1. Basic Part Information

• Part Name: Clutch Master Cylinder

• Applicable Models: Mainly suitable for HOWO T5G, HOWO TX, and SITRAK series trucks.

• Appearance Features:

  • Reservoir: A translucent plastic reservoir with a black screw cap on top, used to store clutch hydraulic fluid (typically DOT4 brake fluid or specialized clutch fluid).

  • Cylinder Body: Black main body (hydraulic pump housing) with a rubber dust boot at the front end; contains an internal piston pushrod.

  • Mounting Structure: Includes a mounting bracket and bolt holes for installation on the cab floor or pedal bracket.

  • Electrical Connector: A black wiring connector visible on the side, typically for a clutch pedal position sensor or fluid level warning switch.

2. Function & Operation

• Hydraulic Transmission: When the driver depresses the clutch pedal, the piston inside the master cylinder moves, pressurizing hydraulic fluid. This fluid pressure is transmitted through a high-pressure hose to the clutch slave cylinder (booster cylinder), enabling clutch disengagement and engagement.

• Effort Reduction (Power Assistance): Uses hydraulic principles to multiply the force applied to the pedal, reducing driver effort.

• Protective Mechanism: Built-in return spring and seals ensure quick fluid return and rapid clutch re-engagement when the pedal is released.

3. Common Failures & Maintenance

• Fluid Leakage: Worn seals or loose line connections can cause hydraulic fluid leaks. Symptoms include fluid puddles under the vehicle or a drop in reservoir fluid level.

• Soft Pedal / Incomplete Disengagement: Air in the hydraulic system (needs bleeding), a sticking piston, or clogged lines can reduce or eliminate assist.

• Replacement Recommendation: If severe leakage or internal wear is present, replace the entire master cylinder. After replacement, bleed the system (remove air) and refill with the specified hydraulic fluid.