Here's a general overview of the process. Specific steps might vary slightly depending on the exact model of your F-250. Always consult a repair manual specific to your vehicle's year and model for detailed instructions and torque specifications. A Haynes or Chilton manual would be invaluable.
Tools You'll Need:
* Socket wrench set (metric): Various sizes will be needed.
* Wrench set (metric): For various nuts and bolts.
* Brake line wrench: To avoid damaging brake lines.
* Pliers: Needle-nose and slip-joint.
* Open-end wrench: For bleeding the brakes.
* Brake fluid: DOT 3 or DOT 4, depending on your vehicle's specifications. Use fresh fluid.
* Clean rags or shop towels: To clean up spills and keep things tidy.
* Catch pan: To collect brake fluid.
* Vacuum bleeder (recommended): Makes bleeding the brakes much easier.
* New master cylinder: Ensure you get the correct one for your vehicle.
* Safety glasses: Protect your eyes from brake fluid splashes.
* Gloves: Protect your hands from brake fluid.
Steps:
1. Safety First: Disconnect the negative battery terminal.
2. Fluid Drainage: Open the bleeder valves on all four wheels to relieve pressure in the brake lines. This reduces the amount of fluid that spills when you disconnect the master cylinder.
3. Component Removal:
* Disconnect brake lines: Carefully loosen the brake lines connected to the master cylinder using a brake line wrench. Have a catch pan ready to collect the fluid.
* Disconnect the pushrod: Disconnect the pushrod from the brake pedal. This will vary depending on the setup, but usually involves a simple clip or retainer.
* Remove the master cylinder: Unscrew the bolts holding the master cylinder to the booster. This may require some maneuvering.
4. Installation of the New Master Cylinder:
* Install the new master cylinder: Carefully install the new master cylinder, ensuring it's properly seated and aligned.
* Reconnect brake lines: Tighten the brake lines to the new master cylinder using the brake line wrench. Don't overtighten.
* Reconnect pushrod: Connect the pushrod to the new master cylinder.
* Secure the master cylinder: Tighten the mounting bolts to the specified torque.
5. Bleeding the Brakes: This is crucial to remove air from the brake lines. This step usually starts with the furthest wheel from the master cylinder (usually a rear wheel). Follow the bleeding procedure precisely as outlined in your repair manual. You may need an assistant to pump the brake pedal while you open and close the bleeder valves. A vacuum bleeder makes this significantly easier.
6. Testing: After bleeding, carefully test the brakes. Pump the pedal several times to ensure firm, consistent pressure. If the pedal feels spongy or goes all the way to the floor, you likely have air in the system and need to bleed the brakes again. If you have any doubt about your bleeding procedure seek professional assistance.
7. Reconnect battery terminal: Reconnect the negative battery terminal.
Important Considerations:
* Brake fluid is corrosive: Clean up any spills immediately.
* Proper bleeding is essential: Improper bleeding can lead to brake failure.
* Torque specifications: Always refer to your repair manual for the correct torque specifications for all bolts and nuts.
* Professional help: If you are not comfortable with this repair, take your vehicle to a qualified mechanic. Brake system failure is extremely dangerous.
This is a general guide. Always consult a repair manual specific to your 1990 Ford F-250 for detailed instructions and safety precautions. The information provided here is not a substitute for professional advice.
