Do-it-yourself Ford Focus 2 rear caliper repair

In detail: do-it-yourself repair of the rear caliper ford focus 2 from a real master for the site my.housecope.com.

Image - DIY repair of the rear caliper ford focus 2

Brake system:
1 - the main brake cylinder;
2 - hydraulic drive reservoir;
3 - brake fluid level sensor;
4 - vacuum amplifier;
5 - pedal assembly bracket;
6 - ABS block;
7 - tubes of the main brake cylinder;
8 - tubes of brake mechanisms of rear wheels

The service brake system is hydraulic, double-circuit, with diagonal division of the circuits. One of the circuits of the service brake system provides the operation of the brakes of the left front and right rear wheels, and the other - of the right front and left rear wheels.
In normal mode, when the system is healthy, both circuits work. In the event of failure (depressurization) of one of the circuits, the other circuit provides braking of the car, albeit with less efficiency. The service brake system includes the wheel brakes, pedal assembly, vacuum booster, brake master cylinder, hydraulic reservoir, anti-lock braking system, as well as connecting pipes and hoses.

Image - DIY repair of the rear caliper ford focus 2

Pedal assembly with vacuum booster and master brake cylinder:
1 - brake pedal;
2 - pedal assembly bracket;
3 - vacuum amplifier;
4 - the main brake cylinder;
5 - hydraulic drive tank

The brake pedal is of the suspended type. A brake signal switch is installed in the pedal assembly bracket - its contacts close when the brake pedal is pressed, as well as a switch that issues a signal to the electronic control unit that the brake pedal is pressed. The vacuum brake booster is designed to reduce the force that must be applied to the brake pedal when braking the car by using a vacuum in the intake manifold of a running engine. The booster is located between the brake pedal and the brake master cylinder and is secured with four nuts to the pedal bracket. The vacuum amplifier is non-separable; if it fails, it is replaced with a new one.

Video (click to play).

Image - DIY repair of the rear caliper ford focus 2

Brake master cylinder with reservoir:
1 - the main brake cylinder;
2 - a sealing ring;
3 - hydraulic drive reservoir;
4 - the screw securing the reservoir to the master brake cylinder

The brake master cylinder is attached to the booster housing with two nuts. On top of the cylinder there is a common reservoir for the hydraulic drive of the brake system and clutch, in which there is a supply of fluid. On the body of the tank there are marks of the maximum and minimum liquid levels. A liquid level sensor is installed in the reservoir, which, when the liquid level drops below the MIN mark, turns on the warning lamp in the instrument cluster. The sensor is a reed switch, the contacts of which are closed under the action of a magnet in a float located in the tank. When the liquid level drops, the float is lowered, and the approach of the magnet closes the contacts.
When the brake pedal is pressed, the master cylinder pistons move, creating pressure in the hydraulic drive, which is supplied through pipes and hoses to the working cylinders of the wheel brake mechanisms.

Image - DIY repair of the rear caliper ford focus 2

Front brake caliper

The front wheel brake mechanism is a disc, with a floating caliper, which includes a single-piston wheel cylinder.

Image - DIY repair of the rear caliper ford focus 2

Front brake pads:
1 - inner block;
2 - external block

The brake pads of the front and rear wheels differ in design. The inner pads of the front brakes have spring clips for installation in the piston of the brake cylinder.

Image - DIY repair of the rear caliper ford focus 2

The front brake disc is ventilated for better cooling. The brake pad guide is attached to the steering knuckle, and the caliper is attached with two bolts to the guide pins installed in the shoe guide holes.Protective plastic covers are installed on the fingers. When braking, the pressure of the fluid in the hydraulic drive of the brake mechanism increases and the piston, moving out of the wheel cylinder, made integral with the caliper, presses the inner brake pad against the disc. Then the caliper (due to the movement of the guide pins in the holes of the shoe guide) is shifted relative to the disc, pressing the outer brake pad against it. A piston with a rubber sealing ring is installed in the cylinder body. Due to the elasticity of this ring, a constant optimum clearance is maintained between the disc and the brake pads.

Image - DIY repair of the rear caliper ford focus 2

Rear wheel brake:
1 - shoe guide;
2 - protective covers for guide pin bushings;
3 - guide fingers;
4 - return spring of the parking brake mechanism;
5 - protective cap of the pumping union;
6 - bushings of guide pins;
7 - fitting for bleeding the brake cylinder;
8 - support with a working cylinder;
9 - brake pads;
10 - spring clip of the outer shoe

The brake mechanism of the rear wheel is a disc, with a floating caliper, which includes a single-piston slave cylinder. The design of the rear brake cylinder is very complex, because combines a conventional hydraulic cylinder (similar in design to the front brake cylinder) and a parking brake mechanism.

Image - DIY repair of the rear caliper ford focus 2

Parking brake actuator on caliper:
1 - lever;
2 - lever shaft;
3 - returnable spring

The parking brake drive works as follows. The parking brake cable acts on the drive lever and turns it. The spring returns the actuator lever to its original position. The movement of the lever is transmitted to the threaded rod. During lever travel, the lever shaft causes the threaded rod to move out of the cylinder.

Image - DIY repair of the rear caliper ford focus 2

Rear brake caliper

Image - DIY repair of the rear caliper ford focus 2

Cylinder elements:
1 - threaded rod;
2 - rubber cuff;
3 - threaded bushing;
4 - piston

A bushing is screwed onto the threaded rod, installed in the piston. The threaded bush can be rotated in the piston. Moreover, when the sleeve is pressed against the inner surface of the piston with its conical belt A, turning is very difficult, and if the sleeve moves away from the piston, it turns easily on the thrust bearing. The sleeve in the piston is pressed (through the thrust bearing) by a spring. Thus, as the brake pads wear, the threaded bushing is screwed further from the threaded rod, allowing the piston to exit the cylinder while maintaining a constant parking brake stroke.

Image - DIY repair of the rear caliper ford focus 2

Piston elements:
1 - spring;
2 - washer;
3 - thrust bearing;
4 - sleeve cuff;
5 - piston;
A - tapered collar of the bushing

Image - DIY repair of the rear caliper ford focus 2

This design of the rear brake cylinder determines the way the piston is recessed into the cylinder when replacing the pads. The piston cannot simply be pushed into the cylinder. Using a lot of force will damage the parts. The piston must be screwed in clockwise and at the same time strongly pressed on it to ensure proper friction along the tapered shoulder and screw the sleeve onto the threaded rod of the parking brake actuator.

Image - DIY repair of the rear caliper ford focus 2

Brake pad guide

The shoe guide is attached to the trailing arm of the rear suspension.

Image - DIY repair of the rear caliper ford focus 2

Rear brake pads:
1 - inner block;
2 - external block

The inner pads of the rear brake mechanisms are spring-loaded to eliminate vibrations during the operation of the mechanism.

Image - DIY repair of the rear caliper ford focus 2

The rear brake disc, unlike the front brake disc, is non-ventilated.

Image - DIY repair of the rear caliper ford focus 2

Parking brake lever:
1 - front parking brake cable;
2 - an adjusting nut;
3 - parking brake lever;
4 - parking brake indicator switch

The parking brake lever, fixed between the front seats on the floor tunnel, is connected to two cables through a cable and an equalizer. The rear cable ends are connected to the parking brake actuator levers attached to the rear brake calipers. The parking brake is adjusted by turning the adjusting nut located on the tip of the front cable.
Most vehicles are equipped with anti-lock braking systems (ABS).

Image - DIY repair of the rear caliper ford focus 2

ABS unit:
1 - control unit;
2 - hole for connecting the tube of the master brake cylinder;
3 - hole for connecting the brake tube of the left front wheel;
4 - hole for connecting the brake tube of the right front wheel;
5 - hole for connecting the tube of the brake mechanism of the left rear wheel;
6 - pump;
7 - hole for connecting the tube of the brake mechanism of the right rear wheel;
8 - hydraulic block

Brake fluid from the brake master cylinder enters the ABS unit, and from there to the brakes of all wheels.
The ABS unit, mounted in the engine compartment on the left side member, near the bulkhead, consists of a hydraulic unit, a modulator, a pump and a control unit. ABS operates in response to the signals from the wheel speed sensors. The sensors are inductive.

Image - DIY repair of the rear caliper ford focus 2

The location of the wheel speed sensor on the steering knuckle

The front wheel speed sensor is installed in the steering knuckle hole and secured with a screw. The sensor drive disk is pressed onto the outer CV joint housing.

Image - DIY repair of the rear caliper ford focus 2

Rear wheel speed sensor:
1 - rear wheel hub;
2 - sensor;
3 - sensor fastening screw

The rear wheel speed sensor is attached to the rear wheel hub. If the rear wheel speed sensor fails, the sensor must be replaced.
When the vehicle is braking, the ABS control unit detects the beginning of wheel blocking and opens the corresponding modulator solenoid valve to release the pressure of the working fluid in the channel. The valve opens and closes several times a second, so you can make sure that the ABS is working by a slight tremor of the brake pedal at the time of braking.
ABS has a built-in brake force distribution (EBD) system, which acts as a pressure regulator in the hydraulic drive of the rear wheels brakes. If the rear wheels begin to block when the vehicle is braking, the intake valves of the rear wheel brakes in the modulator switch to the constant pressure maintenance mode, preventing a further increase in pressure in the working cylinders of the rear brakes.
In the event of a malfunction in the ABS, the braking system remains operational, but the wheels may lock. In this case, the corresponding fault code is written into the memory of the control unit, which is read using special equipment at the service center.

Image - DIY repair of the rear caliper ford focus 2

Image - DIY repair of the rear caliper ford focus 2

12. Remove the hold-down spring between the caliper and the caliper. You may have to tinker if it sour

This completes the analysis of the caliper.
Here is a photo of the swing arm seat

Image - DIY repair of the rear caliper ford focus 2

Image - DIY repair of the rear caliper ford focus 2

Image - DIY repair of the rear caliper ford focus 2

Image - DIY repair of the rear caliper ford focus 2

Image - DIY repair of the rear caliper ford focus 2

Image - DIY repair of the rear caliper ford focus 2 Image - DIY repair of the rear caliper ford focus 2

Further assembly in reverse order, applying grease to the required places. Between the flare nut and the piston body, on the piston surface with a thin layer, into the seat of the pivot arm. The boot was washed and smeared with silicone for 3 days. After being wiped off the outside.

Well, everyone here is so smart, I just met with a man today and he has a trick of tatal and so on the one hand, the caliper will not put anywhere on the one hand, and the boot is intact

To select an anther, you need to know the diameter of the piston and its maximum stroke. With this information, you can try to pick up a non-original boot in the store.
Or, for example, look here seinsa. es / en / home / home.asp

and for a 2-liter we get a set of kits:
D4365 Repair kit, Caliper | 54 | ATE front caliper repair kit
D4592 Repair kit, Caliper | 57 | ATE front caliper repair kit DIESEL.
D4612 Repair kit, Caliper | 38 | ATE rear caliper repair kit

having fun in Exist we get:
D4365 price 653,49r delivery time 2 days
compound:
Seinsa B7001 Threaded vent plug
Seinsa B6167 Gasket
Seinsa B4381 Bellow
Seinsa B5069 Bellow
Seinsa B5081 Bellow

Well, etc.
You can look for something cheaper.

Due to my own stupidity, I screwed up the rear right caliper. The question arose about replacing it. Prices for new ones, even non-originals, were not at all pleasing.And after a short search on the parsing, a support from a matryoshka with a fomoko stamp was bought for only 1 tr. The external condition was far from presentable. A layer of oxides mixed with dust from the pads, pieces of oxides even under the boot. But the parking brake mechanism worked. And once you bought it, you need to put it in order.

Here is a photo of the insides of the disassembled caliper

1. Clean from dirt, drain the remaining brake fluid

2. Remove the boot by gently prying it with a flat screwdriver around the perimeter. The boot is reinforced with a metal ring.

3. Press out the piston. Can be compressed air or by turning the hand brake lever

4. The piston consists of five parts. Body 2, cone nut 3, bearing 4, washer 5, spring 6. Easily disassembled. It is enough to pick up the edge of the spring and slander it.

5. Remove the O-ring 12

6. Remove the shaped lock washer 7.

7. Remove the spring 8, washer 9, screw 10 and key 11

8. Remove the return spring from the parking brake swing arm

10. Remove the pivot arm stopper.

11. Remove the swing arm

Here is a photo of the swing arm seat

Further assembly in reverse order, applying grease to the required places. Between the flare nut and the piston body, on the piston surface with a thin layer, into the seat of the pivot arm. The boot was washed and smeared with silicone for 3 days. After being wiped off the outside.

Watch an interesting video on this topic