To remove the front brake caliper, first be sure to apply the handbrake, and to loosen the front wheel nuts, first jack up the front of the car and place it on axle stands, before removing the relevant front roadwheel. Minimise losses of fluid by taking the master cylinder reservoir cap off and sealing it with polythene or brake hose clamp. Clean around the brake hose union on the caliper and slacken and remove the bolt, collecting the sealing washers and plugging the end of the hose to avoid fluid loss and entry of dirt. Remove the old sealing washers and clean spilled fluid with cold water. Next slacken and remove the upper and lower caliper guide pin bolts and lift the caliper away from the brake disc and remove the caliper from the car leaving the brake pads in position. For the overhaul, wipe away dust and dirt from the caliper, withdraw the partially-ejected piston and remove the dust seal. Extract the piston hydraulic seal carefully, and then clean all the parts with suitable cleaning mediums without the use of mineral-based solvents. Check all components for signs of wear or damage and renew any components that are not in good condition, particularly the cylinder bore and piston. If the assembly is suitable for re-use, get a repair kit and replace all rubber seals. On reassembly, make sure all parts are clean and dry, soak the piston and new piston seal in clean hydraulic fluid and install the new piston seal with fingers only. Fit the new dust seal and gently ease the piston in the cylinder bore. If renewing guide pins, lubricate the pin shafts and fit the gaiters, and put the pins in the caliper bracket. Before refitting, fill caliper with fresh hydraulic fluid by slackening the bleed screw and pumping until bubble free fluid comes out. Make sure the brake pads are fitted properly, press the caliper to position, press down and tighten the bolts of the guide pins according to the required torque. Install new sealing washers on both sides of the brake hose union, screw the brake hose union bolt in place, and tighten to the stated torque. Finally, remove any clamps or polythene, bleed the hydraulic system, refit the roadwheel, lower down the car and tighten the roadwheel nuts to the specified torque.