Checking the brake discs

For this you need to remove the wheels. The front wheels are ventilated disc brakes, which thanks to this design dissipate heat well from friction (Fig. 8.11). The rear wheels are set solid wheels (without ventilation holes). When checking the pads should always be inspected and brake discs, even when replacing pads. Disks with scratches, grooves wear, besides deteriorating braking performance, lead to increased wear of the pads.

1. dove disc is not a malfunction.

2. Note the risks and wear marks on the disc. They emerge from the mud or too worn-out shoes. If the depth of ticks greater than 0.5 mm, the disc must be replaced. Ventilated discs threadlike scratches up to 25 mm can not be replaced. However, the increasing need to replace them.

3. Check the runout of the disc - it should not hurt for the pads at their lighter note.

4. Check the thickness of the disk in several places. Measure the best caliper after setting under his jaw to drive two coins (Fig. 8.12) - When the disc worn measurements will be more accurate. Do not forget to subtract the thickness of the coins from the result.

5. Brake discs can not be processed.

6. Worn wheels must always be replaced in pairs.

The dimensions of the brake discs

Dimensions of brake discs for cars with diesel engines are presented in Table. 8.1.

Table 8.1. Dimensions of brake disks of cars with diesel engines

Table 8.2. Dimensions of brake disks cars with petrol engines

Recommendations on maintenance and repair of the brake system

1. If you are anywhere else reveals a closed hydraulic brakes, hydraulic fluid will flow out. This prevents the work, and then will need to top up the brake fluid. This can be avoided as follows: before starting the first open the bleed screw brake the appropriate wheel. Press the brake pedal and hold it. You can use a wooden stick of appropriate length, which should hold between the pedal and the driver's seat. The pistons in the master cylinder in this position, the supply port cover brake fluid, so it does not.

2. When repairing or caliper brake pistons in any case can not be used for the lubrication oil or other substances. Brake fluid must not come in contact with them. In addition, the lubricant will become more liquid when heated and can get into the working surface of the brake mechanism. Needed special lubricants, which tend to have a complete spare parts. When installing the piston in the brake cylinder, for example, uses a special paste for brake cylinder (from the ATE). This material was also applied to the inner side of a new protective anther.

3. Brake Caliper, who during disassembly was completely freed from the brake fluid can bring certain difficulties during the pumping system. Even after repeated brake application liquid may not flow into it. In this case, proceed as follows: after the installation of the upper end of the caliper brake hose is not fixed on the brake lines. Through the open bleed screw, pump the brake fluid until it begins to flow from the upper end of the brake hose. Then fix the brake hose and tighten the bleed screw. After this, bleed the system. For pumping the brake fluid using a new plastic containers filled with brake fluid and connected through a transparent hose with a nipple for pumping. It is necessary to raise the container and pumped into the brake brake fluid without air bubbles.

4. Use caution when handling brake fluid. It is aggressive to paint and is very poisonous. Do not allow it to enter the mouth or open wounds.

5. brake fluid drained from the system, can not be reused. Do not use the liquid from the container, which has long been uncovered. Used brake fluid must be disposed of properly.

6. After working with hydraulic brakes, check the pressure: it repeatedly press firmly on the brake pedal. Then, with the engine running again press down the pedal (200-300 H). System pressure should be maintained, i.e. the resistance of the pedals must not decrease.

7. The rubber brake parts, which hit oil must be replaced.