Toyota introduced the Scion xB in 2004. The following year, the Scion xB was equipped with a 1.5-liter, in-line four-cylinder engine, capable of producing up to 108 horsepower and 105 foot-pounds of torque. The 2005 xB was produced as a five-door wagon. It was offered with the option of two-wheel or four-wheel disc brakes. Over time, the pads on the brakes wear thin due to daily braking habits. When the brake pads wear thin, they need to be replaced. The Scion xB with four-wheel disc brakes has an enclosed emergency brake system inside the rear rotor, appropriately called the rotor/drum.
Remove the torque from the front wheel lug nuts. Turn the nuts counterclockwise with a tire iron to remove the torque, but do not remove the lug nuts yet. Raise the front end of the xB using a 2-ton (or greater capacity) jack. Place jack stands beneath the two front frame rails, just inside the lower control arms underneath the wagon. Remove the lug nuts completely from both front wheels and then remove both front wheels from the Scion.
Remove the caliper mounting bolts from the back of one of the calipers. This project is to be completed one side at a time. This will allow you to use the second side of the vehicle as a visual reference if you get stuck on how to reassemble something. The caliper is the large metal piece that wraps around the rotor. Turn the caliper bolts off of one caliper with a 3/8-inch drive ratchet and socket. Remove the bolts from the caliper completely. Remove the caliper from the brake assembly, using a small pry bar to remove the caliper if necessary.
Place the brake caliper directly behind the brake rotor assembly, on the lower control arm of the xB. The lower control arm is the triangular arm extending from the bottom of the brake assembly to the frame of the wagon. Do not let the caliper hang freely or you will damage the rubber brake hose attached to the caliper. Remove the brake pads from the caliper-mounting bracket, if they have not already fallen out. There is one pad on the front of the bracket and one on the rear, behind the brake rotor. Pull both off by hand.
Lubricate the backing plates or shim plates on the new pads, using a tube of caliper grease. Lightly coat the metal backing plates to reduce brake squealing during the initial wearing in of the pads. Install the new brake pads onto the caliper-mounting bracket so the greased sides are facing away from the brake rotor.
Install a 9-inch or larger C-clamp around the back and inner portion of the brake caliper. Place an old brake pad against the piston, which protrudes from the center of the caliper. Close the C-clamp onto the rear of the caliper and the old brake pad. Continue to turn the C-clamp tighter until the caliper piston has been completely retracted and the brake pad is flush with the inside of the caliper housing.
Install the caliper over the rotor and new brake pads. Install the caliper mounting bolts and tighten the bolts to 25 foot-pounds of torque with a 3/8-inch drive torque wrench. Spray the entire brake assembly down on the completed side, using a can of aerosol brake cleaner spray.
Repeat Steps 2 through 6 to complete the second front wheel. Reinstall both wheels onto the car only after you have confirmed that you've properly tightened the caliper bolts. Set the wheel lug nuts on both sides of the car and snug the wheel nuts to mount the wheels flush. Raise the front of the Scion xB with a jack and remove the jack stands from beneath the front of the car. Lower the vehicle to the ground. Immediately torque the wheel lug nuts to 90 foot-pounds of torque using a torque wrench and socket.
Sit in the driver's seat and slowly pump the brake pedal. It should take you at least three seconds to push the pedal all the way down if you are performing this step correctly. Repeatedly pump the brake pedal at least 10 times, or until the brake pedal stiffens and the brake tension has been reset to normal operating tension. Many shop accidents following a brake job are due to the technician not pumping the brake pedal properly before attempting to test drive the vehicle.
Repeat Steps 1 through 8 to complete the replacement of the rear brake pads, if the Scion xB is equipped with four-wheel disc brakes. The process for the rear pad replacement is identical to the one you just performed on the front brake pads. Make sure you follow all torque specifications directly and heed safety warnings.
