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Dorman M390303 Brake Master Cylinder
Reliable Brake Master Cylinder for Chrysler, Jeep, and Plymouth Vehicles
The Dorman M390303 Brake Master Cylinder is designed to restore proper brake function in select Chrysler, Jeep, and Plymouth models. Engineered with an aluminum body and a 1-inch bore diameter, this master cylinder ensures consistent hydraulic pressure for safe braking performance.
Key Features of the Dorman M390303 Brake Master Cylinder
- Constructed from durable aluminum for corrosion resistance and longevity
- Includes reservoir for fluid storage and easy maintenance
- Two outlet ports with rearward outlet size M10 x 1.0 and secondary outlet thread diameter M12 x 1.0
- 1-inch master cylinder bore diameter for precise hydraulic control
- Package contains the master cylinder only; mounting hardware not included
- Compatible with Chrysler Cherokee, Jeep Grand Cherokee, and Plymouth Prowler models
Detailed Product Description
The Dorman M390303 Brake Master Cylinder is a critical component in the brake hydraulics system, responsible for converting pedal force into hydraulic pressure. Its aluminum construction offers a balance of strength and corrosion resistance, suitable for the demanding conditions faced by Chrysler Cherokee, Jeep Grand Cherokee, and Plymouth Prowler vehicles. The included reservoir simplifies brake fluid management, while the two outlet ports with specific thread sizes (M10 x 1.0 rearward outlet and M12 x 1.0 secondary outlet) ensure compatibility with factory brake lines. This master cylinder features a 1-inch bore diameter, providing the necessary hydraulic pressure for effective braking response.
Common Issues Addressed by This Brake Master Cylinder
- Brake pedal sinking or sponginess due to internal seal failure
- Brake fluid leaks from a worn or damaged master cylinder
- Reduced braking efficiency caused by insufficient hydraulic pressure
- Brake warning light activation related to master cylinder malfunction
- Inconsistent brake pedal feel or travel distance
Installation Notes and Tips
- Ensure brake system is properly bled after installation to remove air
- Verify thread sizes (M10 x 1.0 and M12 x 1.0) match vehicle brake line fittings
- Use recommended brake fluid type for Chrysler, Jeep, and Plymouth models
- Inspect related brake components for wear during replacement
- Mounting hardware is not included; retain original hardware or source separately
Quality Assurance and Warranty Information
Dorman manufactures the M390303 Brake Master Cylinder to meet or exceed OEM specifications for Chrysler Cherokee, Jeep Grand Cherokee, and Plymouth Prowler vehicles. While mounting hardware is not included, the product undergoes rigorous quality control to ensure reliable performance. Warranty coverage details should be confirmed with the point of purchase or manufacturer documentation.
| Brand | Dorman |
|---|---|
| Part Number | M390303 |
| Master Cylinder Bore Diameter | 1 |
| Master Cylinder Material | Aluminum |
| Mounting Hardware Included | No |
| Number of Outlets | 2 |
| Package Contents | Master Cylinder |
| Rearward Outlet Size | M10 X 1.0 |
| Reservoir Included | Yes |
| Secondary Outlet Thread Diameter | M12 X 1.0 |
| Sensor Included | No |
| Thread Pitch | 1.0 |
This part fits 16 vehicles. Search below:
| Year | Make | Model | Position | Notes |
|---|---|---|---|---|
| 2002 | Chrysler | Prowler | N/A | Compatible with 1-inch bore drum brake wheel cylinders. |
| 2001 | Jeep | Cherokee | N/A | Compatible with 1-inch bore drum brake wheel cylinders. |
| 2001 | Plymouth | Prowler | N/A | Compatible with 1-inch bore drum brake wheel cylinders. |
| 2000 | Jeep | Cherokee | N/A | Compatible with 1-inch bore drum brake wheel cylinders. |
| 2000 | Plymouth | Prowler | N/A | Compatible with 1-inch bore drum brake wheel cylinders. |
| 1999 | Jeep | Cherokee | N/A | Compatible with 1-inch bore drum brake wheel cylinders. |
| 1999 | Plymouth | Prowler | N/A | Compatible with 1-inch bore drum brake wheel cylinders. |
| 1998 | Jeep | Cherokee | N/A | Compatible with 1-inch bore drum brake wheel cylinders. |
| 1998 | Jeep | Grand Cherokee | N/A | Compatible with 1-inch bore drum brake wheel cylinders. |
| 1997 | Jeep | Cherokee | N/A | Compatible with 1-inch bore drum brake wheel cylinders. |
| 1997 | Jeep | Grand Cherokee | N/A | Compatible with 1-inch bore drum brake wheel cylinders. |
| 1997 | Plymouth | Prowler | N/A | Compatible with 1-inch bore drum brake wheel cylinders. |
| 1996 | Jeep | Cherokee | N/A | Compatible with 1-inch bore drum brake wheel cylinders. |
| 1996 | Jeep | Grand Cherokee | N/A | Compatible with 1-inch bore drum brake wheel cylinders. |
| 1995 | Jeep | Cherokee | N/A | Compatible with 1-inch bore drum brake wheel cylinders. |
| 1995 | Jeep | Grand Cherokee | N/A | Compatible with 1-inch bore drum brake wheel cylinders. |
* Always verify fitment with your vehicle's VIN if unsure. Submodel & trim restrictions may apply.
This part directly replaces or is cross-referenced with the following part numbers:
Cross-reference numbers are provided for identification purposes only. Always confirm fitment before ordering.