Brake caliper rear and its repair. Piston caliper brake rear

After the traditional drum brakes were replaced by increasingly disk systems, manufacturers had to find a solution to one very pressing problem. The fact is that in disk it is necessary to provide not expansion of pads, but on the contrary - their compression. Consequently, the traditional constructive scheme proved to be unsuitable. However, the decision was found quickly enough. The first effective device, called "brake caliper rear", appeared at the turn of the 50-60s of the last century. How does it work and what are the features of its maintenance and repair?

Schematic diagram of the rear brake caliper of the car

The systematic development of the technology of the production of disc brake systems of the car led to the fact that today the brake caliper support can have two different principal design schemes:

• Fixed;
• The construction of the so-called "floating brace".

The purpose of both schemes is identical. They allow you to turn the brake caliper rear into an active element that pushes the shoes to the wheel. But each of the designs has its own characteristics.

The fixed design of the brake caliper

Such a support consists of a metal central unit fixed on a special pivoting cam and working cylinders with pistons symmetrically placed on both sides of the brake disc. In the inoperative state, the pads are held by the springs in the parallel disk at a certain distance from it. When the brake pedal is depressed, the brake fluid entering simultaneously through a complex hose system drives the pistons, which compress the pads.

This design scheme is considered to be the most efficient for disk systems and is successfully used on cars with high engine power ratings. It is this brake caliper rear mounted on most SUVs, executive cars and sports cars.

Mechanism with floating bracket

The principal structural difference between this system and the traditional disc brake is that one of the pads is always in a static position. The braking process is as follows:

• When the pedal is pressed, the fluid exerts pressure on the piston of the brake cylinder;
• Thanks to the free travel of the clamp, the brake caliper piston leaves the cylinder casing and presses the second brake shoe;
• Continuing its movement along special guides, the clamp presses to the disc and the second brake shoe.

This scheme is often used in various brands of cars. In particular, the rear brake caliper ("Opel" is not an exception) often has a "floating" constructive scheme.

Importance of serviceability

Needless to say, the trouble-free operation of this car system directly affects the safety of the owner of the car, passengers and other traffic participants. Accordingly, the state of these elements requires increased attention to themselves. At the very first signs of malfunctions in the work of the support it is necessary to immediately contact the highly qualified specialists of the car service or service station!

The most common malfunctions

The most common types of faults that are subject to caliper brake rear, are as follows:

• Souring and corrosion of the piston. As a result, the pressure of the brake fluid when the brake pedal is depressed is not sufficient to drive the piston into motion.
• Sealing cuff running. This leads to insufficiently effective clamping of the shoes. In addition, air can enter the system, which will result in insufficiently correct braking of all the wheels of the car.
• Outage of anther. In this case, dust and dirt accumulate between the piston and the cylinder, which leads to a difficult stroke of the piston, as well as to fluid losses.
• Damage to the movable bracket or insufficient tightening. One of the most dangerous failures. If, for example, the brake caliper of the rear right receives a damage to the bracket, then it can simply fall off when the braking is abrupt. The liquid instantly pours out, which will inevitably lead to the failure of the system and the rest of the wheels.

Thus, careful control of the correct operation of the supports is dictated by elementary considerations of common sense, own security and the instinct of self-preservation.

Professional diagnostics

The most effective way to avoid the problems listed above is professional diagnostics, performed by highly qualified specialists using specialized tools and equipment. The diagnostic process includes, as a rule, two stages of work:

• Checking the performance of the brake of each wheel. It is held on a special computer stand under the supervision of qualified experts.
• Visual inspection of calipers. This operation requires the removal of the rear wheels. Check the condition of the staples, body, cylinders and anthers. If damage is found, the parts must be replaced immediately.

Self-diagnosis

If it is not possible to carry out a professional diagnosis, the caliper of the rear brake (left or right - it's not important) can be checked by yourself. True, the results of such an event may be approximate, which means that you will not reveal the problems in a timely manner.

Nevertheless check of serviceability of work of brake system of back wheels is carried out as follows:

• Select a smooth section of the road with a good coverage and with the minimum possible intensity of traffic;
• The car accelerates to a speed of 30 km / h;
• When the specified speed is reached, the clutch is squeezed out (or neutral mode is activated on the automatic transmission), and the brake pedal is pressed into the floor abruptly.

If the machine keeps course stability, then the system is OK. If it begins to enter, it often indicates a malfunction of the support. Determine from which side brake caliper rear defective, easy enough. The machine always "leads" in the opposite direction.

Repair and replacement

Like diagnostic work, and repair of brake calipers is highly recommended to entrust highly qualified specialists. In addition to possessing all the necessary deep theoretical knowledge and rich practical experience, they also have a wide arsenal of specialized tools and equipment.

Typically, the repair of the rear brake stupor includes the replacement of anthers and cuffs, the addition of brake fluid and the reinforcement of the fastening of all structural elements. But this - the so-called current repair, which can handle and the motorist. But cracks on the bracket or on the body of the working cylinder, damage to the guides, deformation of the pistons require intervention by specialists.

Depending on the manufacturer and model of the car, the repair of the calipers of the disc brake system of the rear wheels may have differences and certain nuances, which should be remembered. So, for example, the brake caliper "Lacetti" caliper and in its design, and in principle, and in the arrangement of parts is significantly different from a similar unit, for example, installed on a Toyota Land Cruiser. And since the serviceable and trouble-free operation of this system is a vital factor for any vehicle, maintenance and repair of the rear brake caliper requires a high degree of training and appropriate qualification.

Dismantling and replacing the part with your own hands

However, with the urgent need to replace the rear brake caliper can be made and on their own. To do this, you will need to do the following:

• Under the front wheels you need to install the chocks (brake shoe, building bricks or other items);
• Then use the jack to lift the rear of the car;
• For safety reasons, it will be necessary to place the stops under the rear of the car;
• Then you can dismantle the corresponding wheel;
• Then disconnect the manual brake actuator (if any);
• Remove protective caps from the guides;
• Unscrew the guides with a hexagon, carefully remove the caliper.

An important point. If it is necessary to completely remove the part, you will probably need to disconnect the brake hose. In order to prevent leakage of liquid, you should have at hand a piece of rubber, cellophane or a dense cloth, which plugs the hole of the hose. We must not forget about the need to connect it after installing a new element. Otherwise, the system will not work.

Periodicity of prevention and repair

The modern brake caliper is a sufficiently strong and reliable device, which is out of order and getting serious damage is relatively rare. Nevertheless, for safety reasons it is recommended to carry out diagnostics of this important unit at least once every 6 months. And it's best to trust work of this type to qualified specialists. This, of course, entails certain financial costs, but in return guarantees security and can even save human lives!

So, we found out how the brake caliper of the car is arranged and how it can be diagnosed independently. Good luck!