How to Replace Front Brake Rotors

The serviceability of front brake rotors is determined by several factors. All rotors will show some scoring or grooves without any significant reduction in brake function. If the rotors have significant grooves over ten-thousandths of an inch, they are good candidates for replacement. Another factor to be considered is if they are worn below recommended factory specifications. This is the most common reason for replacement. The minimal thickness is marked on the rotor close to the center, and written in tiny increments, so a micrometer is necessary to measure the thickness. There are two types of rotors, and the procedure is somewhat different for each type. The first type is used mostly on front-wheel-drive vehicles, where the rotor comes off as one single unit. The second is on trucks and older rear-wheel-drive vehicles. This type of rotor houses the front wheel bearings.

Things You'll Need

• Floor jack
• 2 jack stands
• ½-inch drive air gun
• Set of ½-inch drive sockets
• Common screw driver
• 3/8 inch drive ratchet
• Set of 3/8-inch drive sockets
• Set of Allen head sockets
• Wire cutters
• Drip pan
• Set of metric wrenches
• Can of brake fluid
• Hammer

Instructions

Front-Wheel-Drive Vehicles

1. Raise the vehicle and support on jack stands. Remove the wheels. Place the drip pan under the caliper. Loosen the 10 mm bleeder screw on the top of the caliper.

2. Spread the brake pads apart with the common screwdriver. Place the screwdriver in the slot in the center of the caliper where the pads can be seen. With the nose of the screwdriver, pry between the rotor and the pad and pull the caliper outward toward you. The piston is being depressed into its housing as the caliper is pulled out. When the caliper comes to its limit outward, push the caliper back away from you and insert the screwdriver into the inside pad between the pad and the rotor. Once again pull the screwdriver toward you until the caliper piston is compressed into its bore.

3. Tighten the 10 mm bleeder screw. Remove the caliper and support it where it is not hanging on the brake hose. Letting the caliper hang on the brake hose will damage the hose and cause brake failure.

4. Remove the caliper support if it interferes with the removal of the rotor. Some vehicles don't require the removal of the support. Remove the rotor by pulling it off. If it is stuck, hit it with a hammer a few times between the studs.

5. Install the caliper support and caliper in the reverse order they were taken off. Install the wheels and let the vehicle down. Check the brake fluid and fill as necessary to the proper level.

6. Start the vehicle and pump the brakes very slowly until you have a high pedal. Remember that by expanding the calipers they have to re-adjust. You will not have any braking when you first start the car. Do not try to move the car until you have pumped the brake pedal sufficiently to feel a firm pedal.

Rear-Wheel-Drive Vehicles

1. Raise the vehicle and support on jack stands. Remove the wheels. Place the drip pan under the caliper. Loosen the 10 mm bleeder screw on the top of the caliper.

2. Spread the brake pads apart with the common screwdriver. Place the screwdriver in the slot in the center of the caliper where the pads can be seen. With the nose of the screwdriver, pry between the rotor and the pad and pull the caliper outward toward you. The piston is being depressed into its housing as the caliper is pulled out. When the caliper comes to its limit outward, push the caliper back away from you and insert the screwdriver into the inside pad between the pad and the rotor. Once again, pull the screwdriver toward you until the caliper piston is compressed into its bore.

3. Tighten the 10 mm bleeder screw. Remove the caliper and support it where it is not hanging on the brake hose. Letting the caliper hang on the brake hose will damage the hose and cause brake failure.

4. Remove the bearing cap in the center of the rotor. Remove the cotter pin. Remove the large nut that retains the bearings and rotor. Wobble the rotor with your hands and the front bearing will come out.

5. Reinstall the spindle nut with just a few threads. Grabbing the rotor with both hands, pull the rotor off with slight down pressure and with a quick jerk. The spindle nut will grab the rear bearing and seal as you pull the rotor off and come out at the same time.

6. Install the bearings into the new rotor. Grease the bearings first and install the rear large bearing then install the grease seal with the hammer. Install the rotor on the spindle and insert the front small bearing followed by the large washer and the retaining nut.

7. Tighten the retaining nut just until there is no longer any freeplay then tighten an additional 90 degrees. Do not over tighten the retaining nut as it will not allow the bearings to expand and they will wear out rapidly. Install the cotter pin.

8. Install the caliper support and caliper in the reverse order they were taken off. Install the wheels and let the vehicle down. Check the brake fluid and fill as necessary to the proper level.

9. Start the vehicle and pump the brakes very slowly until you have a high pedal. Remember that by expanding the calipers they have to re-adjust. You will not have any braking when you first start the car. Do not try to move the car until you have pumped the brake pedal sufficiently to feel a firm pedal.

Tips & Warnings

• Make sure the brakes work before you put the car in gear.