Did you notice that during braking your car is pulled to the side and to stop it you need a greater distance than usual? Do you think you need to press the brake pedal with greater force than usual? Do you feel the smell of smoke after braking? Has the engine slowly reached the desired speed, and has the car’s ability to move by itself deteriorated? It’s probably time to repair the brake caliper.
How brake caliper is made?
The caliper is an important element of the disc braking system. It is used for attaching and fixing the brake pads, ensuring their mobility during braking. Currently, there are 2 types of brake caliper: floating and fixed.
Floating calipers usually have a piston, and sometimes – two, located both on the same side of the brake disc. The caliper housing is attached in support, which in turn is gripped by the steering joint with the help of screws, the brake pads are mounted on the caliper bracket.
For better mounting of the brake pads in the guide grooves, special springs are used. When the brake pedal is pressed, the piston exits the cylinder and acts on the inner brake pad. After that, the caliper bracket moves along the guide pins and tightens the outer brake pad on the disc.
The caliper with fixed construction does not include guide pins, and the pistons are located on both sides of the brake disc. Thus, when braking, the liquid under pressure is sent to all cylinders simultaneously, causing the movement of both the inner and outer plates. The plates are kept apart by means of the spacing springs.
Why is the brake caliper stuck?
The most common reasons that cause the caliper to get stuck are:
- Exposure to moisture and dirt. The accumulated dirt prevents the free movement of the pistons and guide pins. Moisture causes corrosion, which leads to blockage. If the rubber sleeves, which are designed to protect the moving parts from the aggressive action of the environment, are damaged, it increases the risk of piston and pin failure. Locking can also occur when the brake fluid is not changed in time: as it is hygroscopic, it eventually accumulates water, which leads to corrosion of the piston and pin.
- Use of improper lubricant or the lack of it. A special grease resistant to high temperatures must be used for lubricating the guide pins. Inappropriate grease tends to dry or leak, damaging the rubber parts as well. The guide pin cannot move freely in an inflated sleeve.
- Sudden changes in temperature. These have a negative impact on the rubber sleeves. It speeds up the corrosion process and can cause the brake disc to bend, often causing the brakes to lock.
- Wear of the caliper elements. A caliper with the worn casing or piston surface can tilt or lock. The dirt accumulated in the places of wear hinders the free movement of the moving parts. Air penetration speeds up corrosion.
- Deformation. Due to incorrect installation, heavy loads or inadequate operation of the means of transport, the guide pins can bent, which also increases the risk of blocking.
- Using the car with worn brake pads and discs. To ensure a good grip of a worn pair, the plunger may protrude excessively from its support, which may cause it to tilt.
- Use of improper brake fluid. If the fluid is too viscous, the pistons will not return to their original position. In addition, pistons made of polymeric or composite material may swell upon contact with an inappropriate liquid.
- Exposure to strong chemicals. Substances on the road and the brake fluid determine the premature wear of the rubber sleeves, which is why it is important to keep the system tight.
6 Rules for the correct use of brake calipers
- Clean and lubricate the brake system components and check the condition of the sleeves each time you change the brake pads, or every 6 months. Replace damaged seals immediately.
- Change the brake fluid in time. This is hygroscopic, which means that over time it increases the amount of water in its composition. This affects the braking efficiency and determines the internal corrosion of the pistons.
- Choose the lubricants that suit your car model. Usually, for EP lubrication of anti-noise pads, clamping springs and the outer part of the brake pads, an EP grease is used, with the addition of copper or molybdenum. For the substrates of the plates, it is recommended to use ceramic lubricants. The guide pins must be lubricated with mineral-based products, intended for use at temperatures between -45 ° C and +180 ° C (-49F to 356 F). There are also universal synthetic lubricants, suitable for use with all moving elements of the braking system. When lubricating the unit, you should apply only a small amount of lubricant to the sleeves to prevent it from leaking onto the friction gasket. You should also avoid getting the EP greases on the sealing elements.
- Avoid aggressive driving style. When driving on mountain roads, frequent brake pedal pressure becomes inevitable. But under normal conditions, sudden start and braking should be avoided. This will help prevent braking system elements to overheat.
- When replacing the brake pads, use a special tool to press the piston into the cylinder. Make sure the piston does not tilt.
- To delay or prevent corrosion, apply special paint that is resistant to high temperatures on the caliper. The surface should first be polished with sandpaper and degreased. The paint will not only protect the brake caliper from damage but will also give your car personality.
The brake caliper is a car part that should never be neglected. Its smooth operation ensures the efficiency of the braking system, as well as your and passengers’ safety. Ignoring the first signs of brake caliper damage can cause the disc to crack or complete brake failure. For the caliper to serve you well, just follow the recommendations above.