When your ABS warning light comes on in your vehicle, it might be time to get down and dirty. First, check the fuses connected to your ABS system. There may be a couple of these to check, so make sure you look in the owner?'s manual for all possible fuses and their respective locations. If you find a bad fuse, exchange it with a new one and check to see if the ABS warning light is still on. If it does not stay lit after changing out the fuse, then your problem is solved. If it does remain lit, you will need to clean your ABS sensors.
Safety, as it is in every situation, will be the most important factor in this process. When preparing your vehicle for this endeavor, there are certain steps to take to ensure all goes well while work is in progress. Be sure to chock the tires so the car does not roll backwards and off the jack stands. Set the parking brake as well. Before raising the vehicle, remove the hub cap from the tire from which you will be working and loosen the lug nuts. Loosen every other lug nut until all lug nuts are loose, but do not remove any lug nuts until the tire is in the air. Using a jack, raise the front end of the vehicle and place a jack stand under each side of the frame. This will allow you to turn the wheels from side to side and let you get to difficult areas under the vehicle.
Once the vehicle is in the air, remove the lug nuts and the tire. Then remove the brake caliper by taking out the two bolts from the back of it. The brake caliper is the curved piece that rests on the brake rotor. Once the caliper is off, be sure to set it on something to keep the brake line from being stressed. Putting stress on this brake line can cause serious damage and eventually lead to brake failure. With the caliper off, pull off the brake rotor and set this aside. You can now get to the ABS sensor located on the steering knuckle. The sensor is usually held in place with a hex bolt. Unscrew the hex bolt and gently remove the sensor. Clean the sensor with a rag removing any carbon buildup and gunk on it. Now, with a clean ABS sensor, you can clean the teeth within the steering knuckle and on the wheel bearing.
On the back side of the steering knuckle, unbolt the bolts that attach it to the wheel bearing. On the front, pry the dust cover off with a screwdriver. Under the dust cover, you will find the spindle nut. This can be removed with a standard ratchet. The size of the socket will vary depending on the vehicle type. Once the spindle nut is off, gently slide out the wheel bearing from the steering knuckle. Notice the teeth and the dirt and grime on them. This will trigger your ABS warning light. The same will occur with dirt on the inside of the steering knuckle as well. Clean both with a rag and pipe cleaners. With the inside and outside and sensor clean, you can begin putting the unit back together.
Replacing everything in the unit will typically work in the reverse order of disassembling it. Begin by reinserting the wheel bearing into the steering knuckle. Be sure to align the ABS sensor ring in the same position that it was in before disassembly. Reinstall the spindle nut and dust cover along with the bolts from the backside of the steering knuckle. Replace the ABS sensor ring and secure with the hex bolt. Reset the rotor over the threads. Installing a lug nut on the bottom thread helps to hold the rotor in place while resetting the brake caliper.
Without resetting the brake caliper before reinstalling it, it can be a difficult task to replace it. To reset the caliper, take out the brake pad from the side opposite of the pistons and leave the pad in place on the piston side. Using a C-clamp, place it on the brake pad and backside of the pistons. Tighten the clamp to compress the piston. This will allow the caliper slide back on to the rotor with ease. Replace the caliper with the same bolts. Before replacing the wheel, make sure all the wires and lines are attached and secure. This will keep them from snagging or tearing on something after completion. Replace the wheel and secure it with lug nuts. The lug nuts do not need to be completely tightened until after the wheel is lowered.
Once the wheel is secured, lower the vehicle, remove the jack stands from under the vehicle and tighten the lug nuts with a lug wrench. Remove the chock blocks and take off the parking brake. Start the vehicle and take it for a test drive. If the ABS warning light comes on, it may be a faulty sensor and needs to be replaced. If the warning light does not come on, then consider it a successful mission and enjoy the ride.
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