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Dorman M39846 Brake Master Cylinder
Dorman M39846 Brake Master Cylinder
The Dorman M39846 brake master cylinder is a direct replacement for select 1988 Toyota 4Runner and Toyota Pickup applications. Built with a cast iron body, integrated reservoir, and sensor provision, it is engineered to match the original master cylinder’s design, function, and performance.
Key Features
- Direct replacement brake master cylinder for select Toyota vehicles
- Cast iron master cylinder construction for durable service
- Reservoir included for a complete hydraulic assembly
- Sensor included for vehicles equipped with the original sensor setup
- 0.938 in. bore diameter for OE-style brake pedal and hydraulic response
- Two outlet design with M10 x 1.0 rearward outlet thread
- Part number M39846 for easy identification and ordering
Detailed Description
Dorman M39846 is precision-engineered to replicate the original master cylinder used on specific Toyota brake systems. It is made from new, high-quality materials and built to restore proper hydraulic pressure delivery in the brake system. This part cross-references Beck/Arnley 072-8371 and Centric Parts 130.44406 for the same application. Compatible with 1988 Toyota 4Runner and 1988 Toyota Pickup, this brake master cylinder is a practical OE-style replacement when the original unit is worn, leaking, or no longer maintaining consistent pedal feel.
Common Issues It May Solve
- Brake fluid leakage from a worn master cylinder body or seals
- Soft, sinking, or inconsistent brake pedal feel
- Loss of hydraulic pressure in the brake system
- Brake warning light concerns related to master cylinder sensor function
- Reduced braking performance caused by internal master cylinder wear
Installation Notes and Tips
Before installation, verify bore diameter, outlet thread size, and sensor connection against the original unit. Bench bleed the master cylinder before connecting brake lines to help remove trapped air from the hydraulic circuit. Because mounting hardware is not included, reuse or source the correct hardware as needed. After installation, inspect all brake line connections for leaks and bleed the full brake system according to the vehicle service procedure.
Quality Assurance
Dorman designs this master cylinder to match the original part’s fit and function using new materials for dependable replacement service. The M39846 is built for specific Toyota brake applications and is intended to support consistent hydraulic performance in the brake system.
| Brand | Dorman |
| Part Number | M39846 |
| Mounting Hardware Included | No |
| Master Cylinder Bore Diameter | 0.938 |
| Master Cylinder Material | Cast iron |
| Reservoir Included | Yes |
| Secondary Outlet Thread Diameter | 10 |
| Sensor Included | Yes |
| Number of Outlets | 2 |
| Package Contents | Master cylinder |
| Rearward Outlet Size | M10 x 1.0 |
| Thread Pitch | 1.0 |
This part fits 2 vehicles. Search below:
| Year | Make | Model | Drive Type | Liters | Cylinders | Position | Notes |
|---|---|---|---|---|---|---|---|
| 1988 | Toyota | 4Runner | 3.0L | V6 | N/A | ||
| 1988 | Toyota | Pickup | 4WD | 3.0L | V6 | N/A | Wheel Cylinder compatible with 1/2 Ton vehicles with a 15/16 inch bore size. |
* 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.