Before starting work, be aware of the dangers of hydraulic fluid and asbestos dust. Begin by applying the handbrake and chocking the front wheels, then slacken the rear wheel nuts, jack up the rear of the car, and support it on axle stands. Remove the roadwheel, and to minimize fluid loss, have an assistant depress and hold the brake pedal while attaching a length of plastic hose to the bleed screw on the caliper, placing the other end in a clean container. Unscrew the bleed screw slightly to allow fluid to flow, then close it when the flow slows and secure the pedal in the depressed position using a pedal jack or a length of wood. Alternatively, use a brake hose clamp to gently clamp the rear flexible hydraulic hose. Clean around the hydraulic union on the caliper and slacken the hose union half a turn before removing the rear brake pads. Unclip the handbrake inner cable fitting from the lever on the caliper and detach the outer cable from the bracket. Undo the caliper from the flexible hose union, being prepared for fluid spillage and plugging or capping the open unions. Currently, no parts are available for overhauling the calipers, so if they are faulty, they must be renewed, although exchange units can be obtained from a Volvo dealer or parts specialist. For refitting, reattach the brake hose to the caliper, finger-tightening the union, then reattach the handbrake cable to the caliper lever and bracket, and refit the brake pads. Tighten the hose union securely, ensuring the hose isn't twisted or kinked, then remove any brake hose clamp or pedal jack and bleed the hydraulic system. Finally, apply the footbrake a few times to settle the pads, refit the roadwheel, lower the car, and tighten the wheel bolts in a diagonal sequence to the specified torque.