Problems with front brakes

You will have to use a c-clamp or brake piston compressing tool to get that piston back in, while you have the brake master cylinder fluid reservoir cap off.

For front brake pads replacement you need only usually wrench set, inclusive 7 mm allen key also. But for rear brake pads replacement you need obligatory a special caliper piston pressing tool, in order to press back rear caliper piston with parking brake automatic adjustment!!! For front brake pads. First you must verify yours front brake disc diameter: 280 mm or 288 mm. (On my car y have 288 mm). After that you can buy the brake pads (with wear sensor). For change front brake pads you must raise vehicle, remove wheels, extract the retaining spring of the caliper, and remove the caliper as follow: 1. Do not disconnect the brake hose from the caliper, and do not allow the caliper to hang by the brake hose! 2. Remove top and bottom caps (on back side of the caliper) for access to guide pins, then unbolt and remove them from the brake carrier. Remove the caliper. 3. Now you must thoroughly clean the brake calipers (free of grease). 4. Remove outer brake pad from brake carrier. 5. Pull inner brake pad out of brake caliper piston. 6. Check up the brake fluid level on the reservor, and emptying if neccessary! 7. Push piston back into brake caliper housing. 8. Install inner brake pad (with expanding spring) in brake caliper piston. (Arrow marked on pad - if exist, must point in direction of brake disc rotation when vehicle is moving forward). 9. Install outer brake pad into brake carrier. 10. Bolt brake caliper housing to brake carrier using two guide pins. Tightening torque is 25 Nm. 11. Install both caps. 12. Insert retaining spring into brake caliper housing. Important: Depress the brake pedal firmly several times while the car is stationary so that the brake pads adjust to their normal operating positions!!! Check brake fluid level and top up if neccessary!!!

Loosen the brake fluid reservoir cap to allow pressure to escape. Use a large C clamp connecting it to the front of the piston and back of the housing. Turn the screw on the clamp to compress the brake piston then release the clamp. The piston will remain compressed allowing you the fit the housing over the new brake pads.

you have an airlock in the system.air compresses fluids dont.bleed the brakes to clear.

caliper bolts are 7 mm Torx head.

SECTION 206-03: Front Disc Brake 2000 Focus Workshop Manual
REMOVAL AND INSTALLATION Brake Pads Removal
CAUTION: If brake fluid is spilt on the paintwork, the affected area must be immediately washed down with cold water.

1. Loosen the wheel nuts.

1. Raise and support the vehicle. For additional information, refer to Section 100-02 .

1. Remove the wheel.

1. Detach the brake hose from the support bracket.

1. Detach the outer brake pad retaining clip.

1. NOTE: Pull the caliper outwards to release the piston.
   Detach the caliper.
   1. Remove the bolt covers.
   1. Remove the bolts.

1. CAUTION: Suspend the caliper to prevent load being placed on the brake hose.
   Support the brake calipers.

1. Lift the outer pad retaining clip over the spring retaining lugs.

1. Remove the outer brake pad.

1. Remove the inner brake pad.

Installation

1. CAUTION: If the caliper piston is retracted into the housing, brake fluid will be displaced from the master cylinder.
   Fully retract the caliper piston.

1. CAUTION: Make sure the brake disc faces are clean before installation.
   Install the inner brake pad.

1. CAUTION: Make sure the brake disc faces are clean before installation.
   Install the outer brake pad.

1. Push the outer retaining clip over the spring retaining lugs.

1. Install the caliper.
   1. Install the bolts.
   1. Install the bolt covers.

1. Install the brake hose onto the support bracket.

1. Locate the outer pad retaining clip.

1. Install the wheels.

1. Check the fluid level in the brake fluid reservoir.

it has front and rear disc brakes, disc brakes are very simple to change out. Most disc brakes have two bolts that hold them on, one on the bottom one on the top on the inside of the brake caliper, they may be an allen head, or just a bolt. Remove them counter-clockwise. After you remove the two bolts, lift up and away on the caliper and the whole assembly will come off. Once you pull the assembly off you will see the two pads, one of them is driven by a piston, the other one is fixed. Remove the fixed one, they just pop off (have little metal clips you may have to slide the pad off). Take a C-clamp or something comparable to squeeze with, place it on the back of the caliper and on the old pad thereby squeezing the cylinder back into the piston, once you squeeze the cylinder back into the piston, it will give you room needed for thicker new brake pads. Piston should retract with the c-clamp fairly easy, shouldn't be a whole lot of resistance. Remove c-clamp after you get it to retract and remove old pad. Put new pad on, just like you took the old ones off. All four are basically the same to change out, they all have two bolts holding them on. You pull those, get the pistons to retract and replace the worn pads, put them back on, line up holes, put bolts back in... and your good to go. When you get back in the car and turn the key on, you may have to pump the brakes a few times.

Sounds like the caliper needs replaced. Sometimes the pistons lock in the caliper and cause the brakes to drag. When the mechanic changed the brakes before, he pushed the pistons in all the way to accomodate the new brake pads. Now that they are wearing back down, it is getting to the warped spot in the caliper and starting to stick.

Installation

1. CAUTION: If the caliper piston is retracted into the housing, brake fluid will be displaced from the master cylinder.
   Fully retract the caliper piston.

1. CAUTION: Make sure the brake disc faces are clean before installation.
   Install the inner brake pad.

1. CAUTION: Make sure the brake disc faces are clean before installation.
   

2. Fully retract the caliper piston

3. Install the outer brake pad.

1. Push the outer retaining clip over the spring retaining lugs.

1. Install the caliper.
   1. Install the bolts.
   1. Install the bolt covers.

1. Install the brake hose onto the support bracket.

1. Locate the outer pad retaining clip.

1. Install the wheels.

1. Check the fluid level in the brake fluid reservoir.

if you are having problems with getting the piston to move back to fit the pads in, you need to screw the piston in using an allen key.
if you have forcefully tried to push it in it may be permanently damaged.

This might sound dumb, but if you haven't used a C-Clamp to push the piston in the caliper back in, then you will not be able to get it back on. Also the guides for the two bolts will need to be gently pushed back so they are not in the way of the bracket. Hope this helps.
Chris