In case overhaul has been recommended by the problems such as fluid leakage, frozen piston, or broken bleeder screw, check every possible solution before commencing the process. Calipers that are new and factory rebuilt are exchanged on a basis of exchange, making the job easy. When rebuilding calipers, always have rebuild kits on hand and in either case, rebuild or replace these calipers in pairs. The first step is to loosen the lug bolts that hold the wheel, to engage the parking brake, to raise up the front part of the car and make sure that the front part is put on jack stands and then remove the relevant wheel. Wipe the brake system using brake system cleaner and leave the moisture to dry in a drip pan. Reduce the loss of fluids by taking out the master cylinder reservoir cap and covering it with cellophane. Wipe the surrounding of the fitting and unscrew the brake hose fitting nut without und screwing the hose off the caliper. Removing the caliper to get access, do not unconnect the brake hose. Unscrew the caliper in the brake hose, then remove the brake pad, and also take the caliper out of the vehicle. Again wipe the caliper with the brake system cleaner, kick off the partially ejected piston and remove the dust seal. In case the piston cannot be drawn manually, apply compressed air in a cautious manner and a cushion should be provided to avoid breakages. Carefully remove the piston hydraulic seal using a plastic or wooden object so as not to damage the caliper bore. Wipe all the parts using isopropyl alcohol, clean brake fluid, or brake system cleaner, and leave to dry. On VW calipers, remove the spacers of the caliper body bushings and on Girling calipers, remove the guide pins and dust boots. Inspect all elements of wear or damage, especially cylinder bore and piston, which must be changed in case of a scratch, wear or corrosion. In case the assembly can be used any more, get the proper repair kit and re-assemble all the rubber seals, dust covers and caps that have been disturbed during the dismantling. It is essential to make sure that all parts are clean and dry when reassembling, witness the piston and new piston seal in clean brake fluid and apply clean fluid to the surface of the cylinder bore. Insert the new piston seal in the lower groove of the caliper bore with fingers making sure it fits in place. Get the new dust boot past the piston and open the flanged part to the upper groove of the cylinder pushing the piston to the bottom of the bore and passing the lip of the dust boot in. Lubricate the spacers or guide pins with grease of the repair kit or copper-based high temperature brake grease, attach the new dust boots and fix the guide pins into the mounting bracket. Lastly, tighten the caliper to the maximum and attach the brake pads and caliper, tighten the brake line fitting nut, take off the cellophane in the master cylinder reservoir and bleed the hydraulic system. Once there has been minimum loss of brake fluid, then only the concerned front brake should be bled. Install the wheel, drop the vehicle on the ground, and screw the wheel bolts to the required torque.