OE Quality
60-Day Returns

Dorman M39451 Brake Master Cylinder
Reliable Brake Master Cylinder for Chrysler, Dodge, and Plymouth Vehicles
The Dorman M39451 Brake Master Cylinder is engineered to restore proper brake hydraulics in select Chrysler, Dodge, and Plymouth models. Designed with an aluminum body and a 21mm bore diameter, this master cylinder includes a reservoir to ensure consistent brake fluid delivery and performance.
Key Features of the Dorman M39451 Brake Master Cylinder
- Constructed from durable aluminum for corrosion resistance and longevity
- Includes an integrated reservoir for brake fluid storage
- 21mm master cylinder bore diameter for precise hydraulic pressure
- Two outlets with 3/8-24 inch thread diameter for rearward and secondary connections
- Compatible with multiple Chrysler, Dodge, and Plymouth models including Charger, LeBaron, and Town & Country
Detailed Product Description
The Dorman M39451 Brake Master Cylinder is designed to meet the hydraulic braking needs of various Chrysler, Dodge, and Plymouth vehicles such as the Charger, Acclaim, and Sundance. Its aluminum construction provides a lightweight yet durable solution resistant to rust and wear. The 21mm bore diameter ensures accurate pressure generation for effective braking response. This master cylinder comes with a built-in reservoir, eliminating the need for a separate fluid container, and features two outlets with standardized 3/8-24 inch threads for secure brake line connections. Note that mounting hardware is not included with this part.
Common Applications and Issues Addressed
- Restores brake pressure in vehicles experiencing soft or spongy brake pedal feel
- Replaces master cylinders with leaking or damaged reservoirs
- Solves brake fluid contamination or loss due to cracked or corroded master cylinders
- Addresses brake failure symptoms caused by internal seal wear or bore damage
- Ensures proper hydraulic function in Chrysler, Dodge, and Plymouth models listed in the fitment
Installation Notes and Tips
- Ensure brake system is properly bled after installation to remove air pockets
- Verify compatibility with your specific vehicle model and year before installation
- Use appropriate brake fluid as specified by the vehicle manufacturer
- Inspect brake lines and fittings for wear or damage during replacement
- Mounting hardware must be sourced separately as it is not included
Quality Assurance and Warranty Information
Dorman parts are manufactured to meet or exceed OEM standards for fit, form, and function. The M39451 Brake Master Cylinder undergoes rigorous quality control to ensure reliable performance. Warranty coverage details can be obtained from the product documentation or the manufacturer’s website.
| Brand | Dorman |
| Part Number | M39451 |
| Mounting Hardware Included | No |
| Master Cylinder Bore Diameter | 21 |
| Master Cylinder Material | Aluminum |
| Reservoir Included | Yes |
| Sensor Included | No |
| Number of Outlets | 2 |
| Package Contents | Master cylinder |
| Rearward Outlet Size | 3/8-24 in |
| Secondary Outlet Thread Diameter | 3/8-24 in |
This part fits 82 vehicles. Search below:
| Year | Make | Model | Submodel | Position | Notes |
|---|---|---|---|---|---|
| 1994 | Dodge | Shadow | N/A | Brake Master Cylinder with a 21mm bore size | |
| 1994 | Plymouth | Sundance | N/A | Brake Master Cylinder with a 21mm bore size | |
| 1993 | Dodge | Shadow | N/A | Brake Master Cylinder with a 21mm bore size | |
| 1993 | Plymouth | Sundance | N/A | Brake Master Cylinder with a 21mm bore size | |
| 1992 | Dodge | Shadow | N/A | Brake Master Cylinder with a 21mm bore size | |
| 1992 | Plymouth | Sundance | N/A | Brake Master Cylinder with a 21mm bore size | |
| 1991 | Dodge | Shadow | N/A | Brake Master Cylinder with a 21mm bore size | |
| 1991 | Plymouth | Sundance | N/A | Brake Master Cylinder with a 21mm bore size | |
| 1990 | Dodge | Shadow | N/A | Brake Master Cylinder with a 21mm bore size | |
| 1990 | Dodge | Spirit | N/A | Brake Master Cylinder with a 21mm bore size | |
| 1990 | Plymouth | Sundance | N/A | Brake Master Cylinder with a 21mm bore size | |
| 1989 | Chrysler | LeBaron | GTS | N/A | Brake Master Cylinder with a 21mm bore size |
| 1989 | Dodge | Aries | N/A | Brake Master Cylinder with a 21mm bore size | |
| 1989 | Dodge | Lancer | N/A | Brake Master Cylinder with a 21mm bore size | |
| 1989 | Dodge | Shadow | N/A | Brake Master Cylinder with a 21mm bore size | |
| 1989 | Dodge | Spirit | N/A | Brake Master Cylinder with a 21mm bore size | |
| 1989 | Plymouth | Acclaim | N/A | Brake Master Cylinder with a 21mm bore size | |
| 1989 | Plymouth | Reliant | N/A | Brake Master Cylinder with a 21mm bore size | |
| 1989 | Plymouth | Sundance | N/A | Brake Master Cylinder with a 21mm bore size | |
| 1988 | Chrysler | LeBaron | N/A | Brake Master Cylinder with a 21mm bore size | |
| 1988 | Chrysler | New Yorker | N/A | Brake Master Cylinder with a 21mm bore size | |
| 1988 | Chrysler | Town & Country | N/A | Brake Master Cylinder with a 21mm bore size | |
| 1988 | Dodge | 600 | N/A | Brake Master Cylinder with a 21mm bore size | |
| 1988 | Dodge | Aries | N/A | Brake Master Cylinder with a 21mm bore size | |
| 1988 | Dodge | Daytona | N/A | Brake Master Cylinder with a 21mm bore size | |
| 1988 | Dodge | Lancer | N/A | Brake Master Cylinder with a 21mm bore size | |
| 1988 | Dodge | Shadow | N/A | Brake Master Cylinder with a 21mm bore size | |
| 1988 | Plymouth | Reliant | N/A | Brake Master Cylinder with a 21mm bore size | |
| 1988 | Plymouth | Sundance | N/A | Brake Master Cylinder with a 21mm bore size | |
| 1987 | Chrysler | LeBaron | Base | N/A | Brake Master Cylinder with a 21mm bore size |
| 1987 | Chrysler | LeBaron | Premium | N/A | Brake Master Cylinder with a 21mm bore size |
| 1987 | Chrysler | LeBaron | Turbo | N/A | Brake Master Cylinder with a 21mm bore size |
| 1987 | Chrysler | New Yorker | N/A | Brake Master Cylinder with a 21mm bore size | |
| 1987 | Chrysler | Town & Country | N/A | Brake Master Cylinder with a 21mm bore size | |
| 1987 | Dodge | 600 | N/A | Brake Master Cylinder with a 21mm bore size | |
| 1987 | Dodge | Aries | N/A | Brake Master Cylinder with a 21mm bore size | |
| 1987 | Dodge | Charger | N/A | Brake Master Cylinder with a 21mm bore size | |
| 1987 | Dodge | Daytona | N/A | Brake Master Cylinder with a 21mm bore size | |
| 1987 | Dodge | Shadow | N/A | Brake Master Cylinder with a 21mm bore size | |
| 1987 | Plymouth | Reliant | N/A | Brake Master Cylinder with a 21mm bore size | |
| 1987 | Plymouth | Sundance | N/A | Brake Master Cylinder with a 21mm bore size | |
| 1986 | Chrysler | Laser | N/A | Brake Master Cylinder with a 21mm bore size | |
| 1986 | Chrysler | LeBaron | N/A | Brake Master Cylinder with a 21mm bore size | |
| 1986 | Chrysler | New Yorker | N/A | Brake Master Cylinder with a 21mm bore size | |
| 1986 | Chrysler | Town & Country | N/A | Brake Master Cylinder with a 21mm bore size | |
| 1986 | Dodge | 600 | N/A | Brake Master Cylinder with a 21mm bore size | |
| 1986 | Dodge | Aries | N/A | Brake Master Cylinder with a 21mm bore size | |
| 1986 | Dodge | Charger | N/A | Brake Master Cylinder with a 21mm bore size | |
| 1986 | Dodge | Daytona | N/A | Brake Master Cylinder with a 21mm bore size | |
| 1986 | Dodge | Lancer | N/A | Brake Master Cylinder with a 21mm bore size | |
| 1986 | Plymouth | Reliant | N/A | Brake Master Cylinder with a 21mm bore size | |
| 1985 | Chrysler | Laser | N/A | Brake Master Cylinder with a 21mm bore size | |
| 1985 | Chrysler | LeBaron | N/A | Brake Master Cylinder with a 21mm bore size | |
| 1985 | Chrysler | New Yorker | N/A | Brake Master Cylinder with a 21mm bore size | |
| 1985 | Chrysler | Town & Country | N/A | Brake Master Cylinder with a 21mm bore size | |
| 1985 | Dodge | 600 | N/A | Brake Master Cylinder with a 21mm bore size | |
| 1985 | Dodge | Aries | N/A | Brake Master Cylinder with a 21mm bore size | |
| 1985 | Dodge | Charger | N/A | Brake Master Cylinder with a 21mm bore size | |
| 1985 | Dodge | Daytona | N/A | Brake Master Cylinder with a 21mm bore size | |
| 1985 | Dodge | Lancer | N/A | Brake Master Cylinder with a 21mm bore size | |
| 1985 | Plymouth | Reliant | N/A | Brake Master Cylinder with a 21mm bore size | |
| 1985 | Plymouth | Turismo | N/A | Bore: 21 mm; w/Power Brakes | |
| 1984 | Chrysler | Laser | N/A | Brake Master Cylinder with a 21mm bore size | |
| 1984 | Chrysler | LeBaron | N/A | Brake Master Cylinder with a 21mm bore size | |
| 1984 | Chrysler | New Yorker | N/A | Brake Master Cylinder with a 21mm bore size | |
| 1984 | Chrysler | Town & Country | N/A | Brake Master Cylinder with a 21mm bore size | |
| 1984 | Dodge | 600 | N/A | Brake Master Cylinder with a 21mm bore size | |
| 1984 | Dodge | Aries | N/A | Brake Master Cylinder with a 21mm bore size | |
| 1984 | Dodge | Charger | N/A | Brake Master Cylinder with a 21mm bore size | |
| 1984 | Dodge | Daytona | N/A | Brake Master Cylinder with a 21mm bore size | |
| 1984 | Dodge | Rampage | N/A | Brake Master Cylinder with a 21mm bore size | |
| 1984 | Plymouth | Reliant | N/A | Brake Master Cylinder with a 21mm bore size | |
| 1984 | Plymouth | Turismo | N/A | Bore: 21 mm; w/Power Brakes | |
| 1983 | Chrysler | LeBaron | N/A | Brake Master Cylinder with a 21mm bore size | |
| 1983 | Chrysler | New Yorker | N/A | Brake Master Cylinder with a 21mm bore size | |
| 1983 | Chrysler | Town & Country | N/A | Brake Master Cylinder with a 21mm bore size | |
| 1983 | Dodge | 600 | N/A | Brake Master Cylinder with a 21mm bore size | |
| 1983 | Dodge | Aries | N/A | Brake Master Cylinder with a 21mm bore size | |
| 1983 | Dodge | Charger | N/A | Brake Master Cylinder with a 21mm bore size | |
| 1983 | Dodge | Rampage | N/A | Brake Master Cylinder with a 21mm bore size | |
| 1983 | Plymouth | Reliant | N/A | Brake Master Cylinder with a 21mm bore size | |
| 1983 | Plymouth | Turismo | N/A | Bore: 21 mm; w/Power Brakes |
* 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.