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Dorman M390321 Brake Master Cylinder
Reliable Brake Master Cylinder for Chevrolet Astro and GMC Safari
The Dorman M390321 brake master cylinder is designed specifically for Chevrolet Astro and GMC Safari models, providing dependable brake hydraulics performance. This aluminum master cylinder includes a reservoir and features a 1.25-inch bore diameter to ensure consistent braking pressure.
Key Features of the Dorman M390321 Brake Master Cylinder
- Compatible with Chevrolet Astro and GMC Safari vehicles
- Constructed from durable aluminum material
- Includes reservoir for brake fluid
- 1.25-inch master cylinder bore diameter for precise hydraulic control
- Two outlets with rearward outlet size of 1/2-20 and secondary outlet thread diameter of 9/16-18
- Package contains the master cylinder only; mounting hardware not included
Detailed Product Description
The Dorman M390321 brake master cylinder is engineered to meet the specific hydraulic requirements of Chevrolet Astro and GMC Safari models. Its aluminum construction offers corrosion resistance and long-lasting durability. The included reservoir simplifies installation and maintenance by providing an integrated brake fluid container. With a 1.25-inch bore diameter, this master cylinder delivers consistent hydraulic pressure to the braking system, ensuring reliable stopping power. The two outlet ports, sized at 1/2-20 for the rearward outlet and 9/16-18 for the secondary outlet, accommodate standard brake line fittings for straightforward connection.
Common Issues Addressed by This Brake Master Cylinder
- Brake pedal sinking or sponginess due to internal leaks
- Loss of hydraulic pressure affecting braking performance
- Brake fluid reservoir leaks or damage
- Corrosion or wear in the master cylinder bore
- Incompatible or damaged master cylinder causing brake failure
Installation Notes and Tips
- Ensure compatibility with Chevrolet Astro and GMC Safari before installation
- Bleed the brake system thoroughly after installation to remove air
- Use appropriate brake fluid as specified by the vehicle manufacturer
- Mounting hardware is not included; retain original hardware or source separately
- Inspect brake lines and fittings for wear or damage during installation
Quality Assurance and Warranty Information
Dorman manufactures the M390321 brake master cylinder to meet or exceed OEM specifications for Chevrolet Astro and GMC Safari vehicles. The aluminum construction and integrated reservoir contribute to long service life. While mounting hardware is not included, the product undergoes quality checks to ensure proper fit and function. Warranty details should be confirmed through the original product documentation or Dorman's official resources.
| Brand | Dorman |
|---|---|
| Part Number | M390321 |
| Master Cylinder Bore Diameter | 1.25 |
| Master Cylinder Material | Aluminum |
| Mounting Hardware Included | No |
| Number of Outlets | 2 |
| Package Contents | Master Cylinder |
| Rearward Outlet Size | 1/2-20 |
| Reservoir Included | Yes |
| Secondary Outlet Thread Diameter | 9/16-18 |
| Sensor Included | No |
This part fits 14 vehicles. Search below:
| Year | Make | Model | Position | Notes |
|---|---|---|---|---|
| 2002 | Chevrolet | Astro | N/A | Verify vehicle compatibility before purchasing 1.25" bore size drum brake wheel cylinder. |
| 2002 | GMC | Safari | N/A | Verify vehicle compatibility before purchasing 1.25" bore size drum brake wheel cylinder. |
| 2001 | Chevrolet | Astro | N/A | Verify vehicle compatibility before purchasing 1.25" bore size drum brake wheel cylinder. |
| 2001 | GMC | Safari | N/A | Verify vehicle compatibility before purchasing 1.25" bore size drum brake wheel cylinder. |
| 2000 | Chevrolet | Astro | N/A | Verify vehicle compatibility before purchasing 1.25" bore size drum brake wheel cylinder. |
| 2000 | GMC | Safari | N/A | Verify vehicle compatibility before purchasing 1.25" bore size drum brake wheel cylinder. |
| 1999 | Chevrolet | Astro | N/A | Verify vehicle compatibility before purchasing 1.25" bore size drum brake wheel cylinder. |
| 1999 | GMC | Safari | N/A | Verify vehicle compatibility before purchasing 1.25" bore size drum brake wheel cylinder. |
| 1998 | Chevrolet | Astro | N/A | Verify vehicle compatibility before purchasing 1.25" bore size drum brake wheel cylinder. |
| 1998 | GMC | Safari | N/A | Verify vehicle compatibility before purchasing 1.25" bore size drum brake wheel cylinder. |
| 1997 | Chevrolet | Astro | N/A | Verify vehicle compatibility before purchasing 1.25" bore size drum brake wheel cylinder. |
| 1997 | GMC | Safari | N/A | Verify vehicle compatibility before purchasing 1.25" bore size drum brake wheel cylinder. |
| 1996 | Chevrolet | Astro | N/A | Verify vehicle compatibility before purchasing 1.25" bore size drum brake wheel cylinder. |
| 1996 | GMC | Safari | N/A | Verify vehicle compatibility before purchasing 1.25" bore size drum brake wheel cylinder. |
* 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.