1. Introduction
This manual provides essential information for the proper installation, operation, and maintenance of your Dorman M390384 Brake Master Cylinder. This component is engineered to deliver reliable braking performance, matching the design and function of original equipment on specific Mazda Protege models from 1997 and 1998. Constructed from new, high-quality materials, it ensures a safe and durable replacement for your vehicle's braking system.
Please read this manual thoroughly before attempting any installation or service to ensure safety and optimal performance.
2. Safety Information
WARNING: Improper installation or maintenance of brake components can lead to serious injury or death. If you are not experienced with automotive brake system repairs, it is highly recommended to seek assistance from a qualified professional mechanic.
- Always wear appropriate personal protective equipment (PPE), including safety glasses and gloves, when working on brake systems.
- Brake fluid is corrosive and can damage paint and other surfaces. Avoid contact with skin and eyes. In case of contact, flush immediately with water.
- Never mix different types of brake fluid. Use only DOT 3 or DOT 4 brake fluid as specified by your vehicle manufacturer.
- Ensure the vehicle is securely supported on jack stands before working underneath it. Never rely solely on a jack.
- Keep children and pets away from the work area.
- Dispose of old brake fluid and components according to local environmental regulations.
3. Setup & Installation
The Dorman M390384 Brake Master Cylinder is designed for a precise fit and performance. For detailed, vehicle-specific installation procedures, always consult your vehicle's official service manual. The following steps are general guidelines.
3.1 Compatibility
This master cylinder is compatible with the following vehicles:
- Mazda Protege: 1997, 1998
Always verify fitment using your vehicle's specific make, model, and trim level.
3.2 Pre-Installation Checks
- Inspect the new Dorman M390384 master cylinder for any signs of damage during shipping.
- Ensure all necessary tools and new brake fluid (DOT 3 or DOT 4) are available.
- Confirm the replacement part matches the original master cylinder in design and port configuration.
Figure 1: Dorman M390384 Brake Master Cylinder, showing the reservoir and main body.
This image displays the Dorman M390384 Brake Master Cylinder from an angled perspective. It features a translucent white fluid reservoir with a black cap, connected to a silver-colored metal cylinder body. Electrical wiring and connectors are visible, indicating sensor integration. This view highlights the overall assembly and primary components.
3.3 General Installation Steps
- Preparation: Disconnect the vehicle's battery. Place a drain pan under the master cylinder to catch spilled brake fluid.
- Fluid Removal: Use a syringe or turkey baster to remove as much old brake fluid as possible from the reservoir.
- Disconnect Lines: Carefully disconnect the brake lines from the master cylinder. Be prepared for fluid leakage. Cap the lines to prevent contamination and excessive fluid loss.
- Remove Mounting Nuts: Unbolt the master cylinder from the brake booster.
- Remove Old Unit: Carefully remove the old master cylinder from the vehicle.
- Bench Bleeding (Recommended): Before installing the new master cylinder, it is highly recommended to bench bleed it. This involves filling the reservoir with new brake fluid and using a special kit (often included or sold separately) to remove air from the master cylinder itself. Follow the instructions provided with the bench bleeding kit.
- Install New Unit: Mount the new Dorman M390384 master cylinder onto the brake booster, ensuring a proper seal. Tighten mounting nuts to vehicle manufacturer specifications.
- Connect Lines: Reconnect the brake lines to the new master cylinder. Tighten fittings securely but do not overtighten.
- Fill Reservoir: Fill the master cylinder reservoir with new, clean brake fluid to the MAX line.
- System Bleeding: Bleed the entire brake system to remove any air introduced during the installation process. Start with the wheel furthest from the master cylinder and work your way closer. Refer to your vehicle's service manual for the correct bleeding sequence.
- Final Checks: Check for any leaks around the master cylinder and brake lines. Pump the brake pedal several times to ensure a firm pedal feel. Reconnect the battery.
Figure 2: Top-down view of the Dorman M390384 Brake Master Cylinder.
This image provides a top-down view of the Dorman M390384 Brake Master Cylinder. It clearly shows the black cap of the fluid reservoir with warning labels, and the translucent white reservoir body. The main cylinder body extends horizontally, with the piston rod visible at one end. This perspective is useful for identifying fluid level markings and cap orientation.
4. Operation
The brake master cylinder is a critical component of your vehicle's hydraulic braking system. When the brake pedal is pressed, the master cylinder converts the mechanical force into hydraulic pressure. This pressure is then transmitted through the brake lines to the wheel cylinders or calipers, which in turn apply the brake pads or shoes to slow or stop the vehicle.
The Dorman M390384 is a dual-circuit master cylinder, meaning it has two separate hydraulic circuits for safety. If one circuit fails, the other can still provide some braking capability, though with reduced effectiveness.
5. Maintenance
Regular inspection and maintenance of your brake system are crucial for safety and longevity. While the Dorman M390384 is a durable component, proper care ensures its optimal performance.
- Brake Fluid Level: Periodically check the brake fluid level in the master cylinder reservoir. It should be between the MIN and MAX lines. A consistently low fluid level may indicate a leak in the system or worn brake pads, which should be investigated immediately.
- Brake Fluid Condition: Brake fluid can absorb moisture over time, reducing its effectiveness. Consult your vehicle's service manual for recommended brake fluid flush intervals.
- Leak Inspection: Visually inspect the master cylinder, brake lines, and connections for any signs of brake fluid leaks. Address any leaks promptly.
- Pedal Feel: Pay attention to the feel of your brake pedal. A spongy, soft, or low pedal could indicate air in the system or a master cylinder issue.
6. Troubleshooting
If you experience issues with your braking system after installing the Dorman M390384 Brake Master Cylinder, consider the following common problems and potential solutions. Always consult a qualified mechanic if you are unsure about diagnosis or repair.
| Symptom | Possible Cause | Solution |
|---|---|---|
| Spongy or soft brake pedal | Air in the brake system; improper bleeding. | Re-bleed the entire brake system thoroughly. |
| Brake pedal goes to the floor | Internal master cylinder seal failure; severe air in system; major leak. | Inspect for leaks. If no external leaks, master cylinder may be faulty (unlikely for new part) or system still has air. Re-bleed. |
| Brake fluid leak around master cylinder | Loose brake line fittings; damaged O-ring/gasket; cracked reservoir. | Tighten fittings. Inspect O-ring/gasket for damage and replace if necessary. Inspect reservoir for cracks. |
| Brakes drag or remain partially applied | Residual pressure valve issue (unlikely for new part); brake pedal adjustment. | Check brake pedal free play and adjustment. Consult vehicle service manual. |
7. Specifications
Key specifications for the Dorman M390384 Brake Master Cylinder:
- Model: M390384
- Brand: Dorman
- Manufacturer: Dorman Products
- Item Weight: 1.4 pounds
- Product Dimensions: 12.13 x 6.5 x 4.63 inches
- Exterior Finish: Machined
- Material: New, high-quality materials (cylinder housing matches original casting material, rubber components are EPDM compound).
- Standards: Meets rigorous SAE International standards.
- Compatible Vehicles: Mazda Protege (1997, 1998)
- OEM Part Numbers (Cross-reference): 072-9238; 11-2522; 11-3249; 13-2522; 130.45414; 13387; 13616; 13896; 18M806; 355-80067; 83-14414; F142443; M-53414; M901041; M901258; MC142443; MC390384; MC390501; MC510260; BG1R-43-400; BG1R-43-40Z
8. Warranty & Support
8.1 Warranty Information
For detailed warranty information regarding your Dorman M390384 Brake Master Cylinder, please refer to the official Dorman Products warranty policy. This information is typically provided with your purchase or can be found on the official Dorman website.
8.2 Customer Support
If you have questions about installation, troubleshooting, or product compatibility, please contact Dorman Products customer support. You can find contact information and additional resources on the official Dorman website:
