Replacing the front brake caliper Mitsubishi Lancer 9

Design and principle of operation

A rear caliper is a device that contains a brake cylinder with a piston and guides (they move the caliper along the bracket). Pressing the brake pedal is accompanied by an increase in pressure in the brake line, the cylinder pushes out the piston, and it clamps one pad. Due to the fact that the caliper moves slowly along the caliper using guides, conditions are created for uniform distribution of pressure on the two brake pads, and their pressure on the brake disc.

Mechanical design of a hand brake The design of a mechanical hand brake works the same way - the cable moves the lever, which is attached to the caliper casing, and it then squeezes out any of the pads. The arbitrary movement of the caliper within the caliper equally transfers the clamping force to the two pads, which ensures equal pressure on the brake disc. The electric hand brake also has a similar algorithm. The main difference is that an instance of one electric motor model presses on a piston that has a caliper cylinder, while in another it acts directly on a pad.

What does the part consist of and what elements are subject to wear?

The lion's share of the mechanisms used in car brakes are single-piston calipers equipped with a floating caliper. Powerful units have devices with two or even more cylinders. Each system has moving elements, represented by at least one hydraulic cylinder per caliper. There are also several guides and a block pressing system. Hydraulic fittings and the surface of products often wear out.

Along with depreciation on the caliper, accompanying difficulties often arise. Due to the fact that the hydraulic cylinder boot wears out, the surface is susceptible to corrosion and abrasive damage. There is a risk of violation of the geometry of the caliper bracket. A separate group of breakdowns concerns the parking brake element. After all, such products can break not only the working part, but also the installation areas, studs, rods, fasteners, etc.

The service life of a caliper is on average 7-8 years, even in the middle climatic zone of Russia. However, some devices, if the piston is light alloy, may require more frequent repair work, especially if they use original chrome-plated pistons. The prerequisites for the fact that the piston has become unusable and the caliper needs to be repaired/replaced are the following:

• uneven braking of a vehicle;
• deficiency of braking force;
• disinhibition does not occur completely;
• liquid is leaking.

Provides caliper maintenance at affordable prices. We work with all makes and models of cars. Owners of Audi, Passat, Chevrolet, Ford and other vehicles contact us.

Possible faults

List of rear brake caliper problems:

• oxidation of the cylinder piston. As a result: insufficient fluid pressure when pressing the brake pedal (the piston cannot budge);
• depressurization of the cuff sealing the piston. The result: the pads are pressed weaker than the required norm, hence the brake fluid leak. If there is an absolute leak of this fluid, the brake system is filled with air, and the braking efficiency of all wheels drops sharply;
• The cylinder piston protective boot is faulty. Consequences: dirt seeps between the cylinder and the piston and damages the mirror walls that the cylinder has. This reduces braking efficiency and brake fluid leaks;
• The guide anthers are damaged. The result: dirt gets into them, which increases the resistance to the movement of the caliper; the pads distribute pressure unevenly among themselves. In this regard, braking efficiency decreases, and this also leads to uneven and rapid wear of the brake disc;
• insufficient fixation of the caliper bracket, or a crack in the bracket itself. They are the most dangerous malfunctions. Because the pressure of the pads on the disc is uneven - this is the first thing. Secondly, heavy braking can break the bracket, or it will unscrew from the fist. If this happens, the pads will fall out, the cylinder will not be able to hold the piston and fluid will flow from the inside, which will immediately lead to an immediate loss of braking efficiency of other wheels.

Advantages of replacing a brake caliper at the AMT center car service center

• Many years of work experience;
• Team of professionals;
• Reasonable prices;
• Only original spare parts;
• The latest equipment;
• Work guarantee;

A wide range of work, which includes the service of replacing brake calipers, will allow you to quickly and efficiently carry out repair work without extra costs.

AMT car service center is a fast, high-quality repair of motorcycles and cars of any brand with a guarantee on the work performed. Now your car will be in good hands.

Remember! Contact a specialized car service immediately if you:

• We felt that the car behaved differently on the road;
• The brakes are weakened or, on the contrary, it is necessary to apply more force;
• Hear extraneous sounds, knocks, creaks;
• Noticed the brake pedal pulsating when pressed;
• Brake fluid leaks.

All this suggests that the brake system will be repaired, namely, the brake caliper will be replaced .

Rear caliper diagnostics

It happens in two stages:

• comparison of the deceleration efficiency of all wheels;
• the caliper is subjected to visual inspection.

To compare the deceleration efficiency of each wheel, you need to check it using a computer stand. If this is not possible, then a flat horizontal asphalt section is needed to accelerate the car to thirty kilometers per hour, followed by squeezing the clutch (on the “automatic” you need to put it in neutral) and sharply pressing the brake all the way. These steps will allow you to determine the condition of the brake calipers. Moreover, the make of the car and the presence of ABS are unimportant. If each caliper is working properly, the car will not show any signs of skidding. If any caliper is ineffective or faulty, the car will skid. A skid will allow you to feel how the axle in the car turns more strongly - this will easily help you identify a faulty caliper.

A car with a faulty caliper has a tendency to skid in the direction opposite to the caliper.

Checking the brake system:

• If your car has a jack, you can use it to lift the car. If there is none, find an inspection hole;
• install supports;
• remove the rear wheels and inspect the caliper;
• carefully check the condition of the cylinder, or rather, the anthers and guides. If there are cracks, breaks and holes, then it is necessary to dismantle the caliper in order to thoroughly check the condition for possible repairs or replacement of anthers;
• You will need an assistant to press the brake pedal firmly several times. This is necessary to confirm that there are no brake fluid leaks. Next, the assistant tightens the handbrake several times, and at this time it is necessary to inspect the action of its drive by rotating the brake disc. Such actions will help assess the condition of the handbrake drive mechanism. If it is difficult to rotate the wheel after you stop pressing the brake pedal, the rubber piston seal must be replaced. Because it is like a spring - it pushes the piston back into the cylinder after the fluid pressure decreases.

How to remove a brake caliper

Removing the brake caliper:

• you need to lift the rear of the car;
• remove the side being repaired from the wheel;
• disconnect the handbrake drive. In cars with an electric handbrake, to remove the caliper you must resort to various devices and techniques (see the car repair instructions);
• Remove the cap covers from the guides. You can unscrew them with a hex key;
• Let's start removing the caliper mechanism. It can be removed with two hands, but sometimes you need a screwdriver.

If it is necessary to completely dismantle the caliper mechanism, proceed to unscrewing the tip of the brake hose. To avoid leakage of the brake fluid, you need to plug the unscrewed hose with a piece of rubber. You also need to cover the inlet hole of the caliper mechanism with a similar piece.

Examples of our work

Toyota Land Cruiser brake caliper rebuild

On Toyota Land Cruiser 80,100,200 and Land Cruiser Prado 120,150, the problem of brake caliper piston jamming is common.

Causes: Destruction (tears, cracks, drying out) of the anthers and internal cuffs of the brake cylinder. This causes moisture and dirt to enter the inside of the brake caliper, causing the piston to corrode and seize.

What caused it: 1. Unqualified replacement of brake pads. 2. Untimely replacement of brake pads, which leads to overheating of the brake mechanism. 3. Rare replacement of brake fluid (the brake fluid replacement schedule is 30,000 km or two years of car operation).

We rebuild the brake caliper using original spare parts: 1. Brake caliper repair kit (all rubber parts (boots and cuffs) and special lubricant). 2. Brake caliper cylinder pistons.

After the repair and installation of the brake caliper, bleeding of the brake system is MANDATORY. Based on our experience and customer feedback, the brakes work like new.

Repair

So, use a flat screwdriver to remove the boot from the caliper mechanism and inspect the piston surface. If there are traces of rust, it is recommended to completely replace the caliper mechanism. Because rust leads to damage to the mirror of the cylinder walls. Replacing the cuffs is accompanied by removing the piston. There are three methods with their own disadvantages and advantages. Method one: remove the piston without removing the mechanism. If it is known for certain that removing the piston to replace the rubber seals is inevitable, this can be done on the axle. After the caliper mechanism is removed from the bracket, the assistant should smoothly press the pedal. This way we will achieve an increase in pressure in the brake system, which will push out the piston. After squeezing it out, the assistant releases the brake. Advantages: the piston is easily removed. Disadvantages: inconvenient operation process and large loss of brakes.

Method two: the cylinder requires attention, because the piston is removed with an adjustable wrench. Algorithm of actions:

• grab the top of the piston;
• remove it by turning from side to side.

This method often makes sense when the piston needs to be replaced. Because careless movement of the key results in a scratch on the piston surface. The advantage is that the piston is obtained by clamping the caliper mechanism in a vice - which is convenient.

Method three: removing the piston using compressed air. You will need an adapter with a thread that will fit. Once found, we connect the adapter to the caliper mechanism and the compressor. Pump in air until the piston comes out completely. The disadvantages include the need for a compressor and a special adapter; in addition, the piston will be removed quite abruptly, which can lead to damage.

Inspection

After removing the piston, carefully inspect the cylinder walls. If there are scratches or burrs, the caliper mechanism must be completely replaced. We limit ourselves to only the piston, provided that everything else is in good condition.

Restoring functionality

Cleanliness of the workspace is the main thing to adhere to in order to carry out high-quality repairs of the caliper mechanism. Dust or dirt that can get into the gap between the piston and the cylinder will lead to scuffing and damage over time. Therefore, absolute purity must reign.

Rear caliper cylinder. Replacement

Example of a damaged piston

Repair is based on replacing the rubber cuff, and in case of significant damage, the piston. Using a screwdriver, pull out the obsolete cuff and thoroughly rinse the surface of the cylinder with alcohol. When flushing, it is important not to forget to remove the plug from the inlet hole. After washing, be sure to dry it. Each such disassembly requires the mandatory installation of a new cuff. To do this, we lubricate the cylindrical walls, including the landing pad of the seal itself with “brake seal”. We also lubricate the outside of the piston surface with brake fluid. We insert the piston into the caliper mechanism and press it in by hand. If installed correctly, it will move with force, but if installed incorrectly, the piston simply will not press in.

Installation of the caliper mechanism on the machine

After inserting the piston, it becomes necessary to install the caliper mechanism on the machine. Installation is carried out in the same order as removal, only in reverse order. If the brake hose tip is attached to the caliper mechanism using a special bolt, be sure to replace the copper washers. After assembling and installing the caliper mechanism, we bleed the brakes (do not forget to add brake fluid to the reservoir). The assistant presses the brake pedal several times and releases only on command. With the pedal pressed, unscrew the fitting that bleeds the brakes and release the air. We close the fitting and give the command to the assistant to release the pedal. When a “brake leak” appears, put the hose on the fitting and lower it into a transparent container. We pump the brakes until air bubbles finally come out of the hose. Finally, we install the wheel back and lower the car.

Caliper repair

Always promptly diagnose the operation of the entire brake system of your car. Check the wear of the brake pads and discs and the correct operation of the calipers. Car operating conditions in Russia are close to extreme. The reagents that are used to treat road surfaces in winter cause enormous damage to the rubber components of the chassis and metal parts. Caliper boots, pistons (brake cylinders), and guides are subject to premature wear. The consequence is that the brake system begins to jam, the brake pads and discs wear out, and the car “steals” when braking... The problem can be solved by completely replacing the calipers or repairing them. New calipers are expensive and not everyone can afford them; moreover, there is not always a need to replace the part with a new one. Often the caliper needs to be repaired. What is needed for this: Well, firstly, certain knowledge and skills. Secondly, proper selection of the repair kit. There are kits consisting only of a set of boots and piston rings; some also add the cylinder itself. The need to replace the brake cylinder is determined by the local technician. As a rule, if a problem is detected in a timely manner, it is enough to replace only the rubber components. Rest assured, repaired calipers will work no worse than new ones! Repair of brake calipers in stages: 1. The brake caliper is completely removed from the car, disconnected from the brake fluid supply hoses; 2. The brake caliper is completely disassembled, the piston (brake cylinder) is removed, all boots and rings are removed; 3. The technician thoroughly rinses the caliper, cylinder, all moving components, and applies a special lubricant; 4. Reassemble the brake caliper in the reverse order with the installation of new rings and boot. Practice shows that a repaired caliper (“original”) will serve you longer and better than a new, non-original analogue. In any case, the decision to replace the caliper with a new one, or repair the old one, is up to you.

For example, the cost of a new caliper on an INFINITI FX is from 15 thousand rubles (one), while a repair kit will cost you about 1-5 thousand (a set for 2 calipers, depending on the design and configuration). The cost of replacing 1 caliper (new) will be about 1-2 thousand, the cost of repairs varies from 2 to 5 thousand (depending on the complexity of the work. The arithmetic is simple: replacing 2 front calipers for the specified car will cost from 32 thousand, repairs from 4 to 8 thousand with all spare parts! The price depends on the completeness of the repair kit. The most expensive elements are pistons (900-1500 per piece depending on the car model)

Front caliper malfunctions

The front caliper has a relatively simple design.
Its guides are protected from dirt by durable anthers. Inside the device there are cylinders into which pistons with seals are loaded. Hydraulic pressure is transmitted to them. It forces the pads to press tightly against the discs. The front caliper differs from the rear caliper in that the first is responsible only for the main braking system. The second one is often equipped with an additional handbrake mechanism. It activates the parking brake, which allows the machine to remain in a static position.

How to determine that the front caliper needs to be repaired:

• To stop the car, you need to make an effort;
• the pedal sometimes shakes;
• the pedal is too soft or tight;
• The car skids to the side when braking.

To prevent surface oxidation, a special paint-varnish is applied to the mechanism. However, during operation, the coating peels off due to frequent heating and minor mechanical damage. The hydraulic shut-off valves also wear out and the anthers tear.

The parts become rusty and the guides become sour. Because of this, they jam and they stop moving. To deal with this problem, you need to carry out a bulkhead.

Defective parts must be replaced. To do this, you will have to buy a repair kit in advance. A specialized workshop always has in stock any necessary spare parts and consumables suitable for repairing your brand of car.