Hydraulic Oil Selection for Clutch Master Cylinder
As a core component of the hydraulic transmission system, the choice of hydraulic oil in the clutch master cylinder directly affects the clutch's response accuracy and service life. For manufacturers and users selecting an OEM clutch master cylinder, choosing the correct fluid becomes even more essential to ensure stable long-term performance.
I. Hydraulic Transmission Principle: The Magic of Incompressible Liquid
When the driver depresses the clutch pedal, the master cylinder piston is pressurized, pushing the brake fluid, which is then transmitted to the slave cylinders through a closed pipeline. Utilizing the incompressible property of liquid, the mechanical force applied by the pedal is amplified into hydraulic energy, pushing the release bearing to achieve rapid clutch disengagement and engagement. Many reputable manufacturers, especially those engaged in factory supply clutch master cylinder production, design their cylinders based on these principles to ensure consistent responsiveness. This process is similar to a “relay race of force,” with the hydraulic fluid completing pressure transmission within 0.3 seconds, ensuring smooth gear shifting.
II. Brake Fluid Selection Standards: DOT3/DOT4
1. Mainstream vehicle models require brake fluid conforming to DT3/DOT3 or DT4/DOT4 standards. The fluid must possess the following characteristics:
2. High-Temperature Stability: Boiling point must be above 230℃ (dry state) and 155℃ (wet state) to avoid vapor lock during frequent gear shifts;
3. Low-Temperature Flowability: Kinematic viscosity ≤1800mm²/s at -40℃ ensures rapid response in cold environments;
4. Corrosion Resistance: Protects metal parts and rubber seals, preventing aging and leakage.
Because hydraulic systems are sensitive, choosing fluids recommended by a trusted clutch master cylinder supplier helps ensure compatibility and reliability.
III. Key Precautions：
1. Mixing fluids is strictly prohibited. Vehicles requiring DOT3 from the manufacturer can be upgraded to DOT4, but the reverse is not permitted.
2. Some AMT transmissions require ATF fluid; this must be confirmed by checking the reservoir cap markings.
Regular Inspection and Replacement：
Brake fluid is prone to absorbing water and deteriorating; it is recommended to replace it every 2 years or 40,000 kilometers. If the fluid becomes cloudy, the pedal feels weak, or there is continuous pressure loss, the master cylinder seal must be checked immediately.
Operating Instructions：
1. Air must be purged before adding fluid to prevent air locks that could cause clutch failure.
2. Prioritize original equipment manufacturer (OEM) or other certified brands. Speaking of which, I have to recommend KOMP Auto Parts Company. It's a brake cylinder and clutch cylinder factory from China. Their products are affordable, high-quality, and come with a 1-year or 30,000km warranty.
Special Note: Professional racing cars or vehicles operating under extreme conditions may require DOT5.1 standard fluid; however, do not blindly upgrade civilian vehicles.
As a core component of the hydraulic transmission system, the choice of hydraulic oil in the clutch master cylinder directly affects the clutch's response accuracy and service life. For manufacturers and users selecting an OEM clutch master cylinder, choosing the correct fluid becomes even more essential to ensure stable long-term performance.
I. Hydraulic Transmission Principle: The Magic of Incompressible Liquid
When the driver depresses the clutch pedal, the master cylinder piston is pressurized, pushing the brake fluid, which is then transmitted to the slave cylinders through a closed pipeline. Utilizing the incompressible property of liquid, the mechanical force applied by the pedal is amplified into hydraulic energy, pushing the release bearing to achieve rapid clutch disengagement and engagement. Many reputable manufacturers, especially those engaged in factory supply clutch master cylinder production, design their cylinders based on these principles to ensure consistent responsiveness. This process is similar to a “relay race of force,” with the hydraulic fluid completing pressure transmission within 0.3 seconds, ensuring smooth gear shifting.
II. Brake Fluid Selection Standards: DOT3/DOT4
1. Mainstream vehicle models require brake fluid conforming to DT3/DOT3 or DT4/DOT4 standards. The fluid must possess the following characteristics:
2. High-Temperature Stability: Boiling point must be above 230℃ (dry state) and 155℃ (wet state) to avoid vapor lock during frequent gear shifts;
3. Low-Temperature Flowability: Kinematic viscosity ≤1800mm²/s at -40℃ ensures rapid response in cold environments;
4. Corrosion Resistance: Protects metal parts and rubber seals, preventing aging and leakage.
Because hydraulic systems are sensitive, choosing fluids recommended by a trusted clutch master cylinder supplier helps ensure compatibility and reliability.
III. Key Precautions：
1. Mixing fluids is strictly prohibited. Vehicles requiring DOT3 from the manufacturer can be upgraded to DOT4, but the reverse is not permitted.
2. Some AMT transmissions require ATF fluid; this must be confirmed by checking the reservoir cap markings.
Regular Inspection and Replacement：
Brake fluid is prone to absorbing water and deteriorating; it is recommended to replace it every 2 years or 40,000 kilometers. If the fluid becomes cloudy, the pedal feels weak, or there is continuous pressure loss, the master cylinder seal must be checked immediately.
Operating Instructions：
1. Air must be purged before adding fluid to prevent air locks that could cause clutch failure.
2. Prioritize original equipment manufacturer (OEM) or other certified brands. Speaking of which, I have to recommend KOMP Auto Parts Company. It's a brake cylinder and clutch cylinder factory from China. Their products are affordable, high-quality, and come with a 1-year or 30,000km warranty.
Special Note: Professional racing cars or vehicles operating under extreme conditions may require DOT5.1 standard fluid; however, do not blindly upgrade civilian vehicles.