Here's a general outline. Specific steps and torque specifications will vary slightly depending on the Bronco's trim and brake configuration (rear drum brakes are different from disc brakes). Consult a repair manual specific to your 1990 Ford Bronco for detailed instructions and diagrams. A Haynes or Chilton manual is a good investment.
Tools You'll Need:
* Jack and jack stands
* Lug wrench
* Wheel chocks
* Socket wrench set (metric)
* Torque wrench
* C-clamp (optional, but helpful for compressing caliper piston)
* Brake caliper piston compression tool (highly recommended)
* Wire brush or wire wheel
* Brake cleaner
* New brake rotors
* New brake pads (highly recommended to replace these at the same time)
* Penetrating lubricant (like PB Blaster)
Steps (for front disc brakes):
1. Safety First: Park on a level surface, engage the parking brake, and chock the rear wheels. Raise the front of the Bronco securely using the jack and place it on jack stands.
2. Remove the Wheel: Remove the lug nuts and take off the wheel.
3. Remove the Caliper:
* Use a socket wrench to remove the caliper mounting bolts. Sometimes these are stubborn; penetrating lubricant applied beforehand can help.
* Carefully support the caliper with a bungee cord or wire to prevent it from dangling and stretching the brake hose. Do *not* let the caliper hang by the brake hose.
4. Compress the Caliper Piston: This is crucial. Use a C-clamp and appropriate sized block of wood or a specialized piston compression tool to slowly push the piston back into the caliper. This creates space for the new, thicker rotor.
5. Remove the Old Rotor: The rotor should now be easily removable. It may be held on by a single screw or simply pressed on. If stuck, gently tap it from the back with a hammer and punch. Clean the hub thoroughly with a wire brush.
6. Install the New Rotor: Carefully install the new rotor onto the wheel hub. Make sure it sits flush and is properly centered.
7. Install the Caliper and Pads: If replacing brake pads, install the new pads. Then remount the caliper, ensuring it slides smoothly on the caliper pins. Torque the caliper mounting bolts to the manufacturer's specifications (consult your repair manual).
8. Replace the Wheel and Lug Nuts: Install the wheel and tighten the lug nuts in a star pattern (opposite nuts first) to the manufacturer's specified torque. Do not overtighten.
9. Lower the Vehicle and Repeat: Lower the vehicle, and repeat the process for the other front wheel. For rear disc brakes, the process is similar, although rear calipers might have a different mounting method. Rear drum brakes require a different procedure altogether.
10. Pump the Brakes: After reinstalling everything, get into the vehicle and pump the brakes several times to restore brake pressure.
11. Test Drive: Perform a test drive, cautiously at first, to ensure proper braking performance. If you hear any unusual noises or the brake pedal feels spongy, immediately stop and re-check your work.
Important Notes:
* Brake fluid: You might have a slight leak of brake fluid when compressing the caliper piston, so have some rags on hand.
* Anti-seize compound: Apply a thin layer of anti-seize lubricant to the caliper mounting pins to prevent them from seizing in the future.
* Proper torque: Using a torque wrench is essential to prevent damage to your brake system.
This is a general guide; your 1990 Ford Bronco's specific details may differ. Always refer to a repair manual specific to your vehicle for precise instructions and torque specifications. If you're unsure about any step, it's best to consult a qualified mechanic. Improper brake work can be extremely dangerous.
