Rules for handling brake fluid
Brake fluid is poisonous. Never suck it up by mouth or through a hose. Store brake fluid only in bottles that cannot be accidentally accessed.
When handling brake fluid, the following rules must be observed:
Brake fluid is aggressive and must therefore not come into contact with the vehicle's paintwork. If this occurs, immediately wipe the contact area and rinse with water.
Brake fluid is hygroscopic, i.e. it absorbs moisture from the air. Store brake fluid only in closed containers.
Attention! Make sure that children do not accidentally drink the brake fluid.
Brake fluid that has already been used once in the vehicle's brake system must not be used. When removing air from the brake system, also use only new fluid.
Brake fluid specification: DOT4.
Attention! The brake fluid level in the reservoir must be between the MAX and MIN·marks.
Brake fluid must not come into contact with mineral oil. Even slight traces of mineral oil make the brake fluid unfit for consumption or lead to brake system failure. Cuffs and gaskets of the brake system are damaged by contact with mineral oils. Do not use cleaning cloths with traces of mineral oils.
Use only new brake fluid to flush and clean brake cylinders, hoses and lines.
Change the brake fluid every 2 years, if possible after the cold season.
Attention! Brake fluid is a hazardous fluid that must never be poured or disposed of with household waste. The local administration should provide information on the nearest brake fluid collection points.
Removal of air from the brake system
After the repair of the brake system, during which it was opened, air may enter the system. In this case, the air must be removed from the system. A sign of the presence of air in the pipelines of the system is the compliance of the brake pedal when pressed. In this case, it is necessary to eliminate the leakage and remove air from the system.
At service stations, the brake system is usually filled with liquid, and air is removed from it using a special device. Note: When using the specified device, the filling pressure of the system should not exceed 1 atm. This operation can also be carried out without the indicated device. In this case, the air from the brake system is removed by rocking the brake pedal, which requires the help of an assistant.
If air has entered any individual brake cylinder, the entire brake system and thus each wheel cylinder must be bled. If only one caliper is replaced or repaired, it is usually sufficient to bleed the corresponding brake cylinder.
Safety note
If one of the chambers of the brake fluid reservoir is completely empty (e.g. if there is a leak in the brake system or if you forgot to add fluid to the reservoir when bleeding), air is sucked into the system, which enters the ABS pump. In this case, the air from the brake system must be removed at the service station using a special device.
Bleeding sequence: rear right brake, rear left brake, front right and front left brake and clutch slave cylinder.
Attention! Carefully open the vent valves so as not to rip them off. It is recommended to spray the valve threads about 2 hours before de-airing with a rust remover. If the valve does not turn away, it is recommended to carry out this operation at the service station.
Keep an eye on the fluid reservoir periodically while bleeding. The liquid level must not drop too low, otherwise air may enter the system through the reservoir. Be sure to fill the system with new brake fluid only.
Remove the brake fluid reservoir cap and set it aside. Fill the system with fluid up to the MAX mark.
Mark with paint the position of the wheels relative to the hubs. This will allow the assembly to install the balanced wheels in their original position. Loosen the wheel bolts before jacking up the vehicle. Raise the car, put it on stands and remove the wheels.
Security measures
The operation of lifting and placing the vehicle on stands is dangerous! Therefore, before carrying out the operation, read Section Jacking and towing Introduction to leadership.
1. Remove the dust cap (1) with vent valve (2) on the wheel cylinder.
2. Clean the valve, put a clean hose on it. Dip the other end of the hose into a bottle half-filled with brake fluid. To unscrew the valve, use a special key (HAZET 1968-N).
3. Position or hold the fluid bottle at least 30 cm above the air vent. This eliminates the possibility of air entering the brake system through the fitting thread.
4. Ask for an assistant «shake» brake pedal until the system is pressurized. This will be felt by the resistance of the brake pedal.
5. After reaching the required pressure, fully push the pedal and hold it with your foot.
6. Turn off the valve on the wheel cylinder with a spanner about half a turn.
7. When liquid begins to flow into the bottle, make sure that the end of the hose in the bottle is always below the level of the liquid.
8. Once the fluid pressure has dropped, close the valve.
9. Repeat the pedal swing process until pressure builds up. Depress the pedal, leave your foot on the pedal, open the bleed valve until the pressure is released, and then close the valve.
10. Repeat the process of de-airing the wheel cylinder until there are no air bubbles in the liquid entering the bottle.
11. Carefully tighten the bleed valve to 7 Nm.
12. After completing the operation, remove the hose from the bleed valve and put the protective cap on the valve.
13. Similarly, following the above sequence, bleed the other brakes.
14. Reinstall the wheels so that the marks made during removal match. Pre-lubricate with a thin layer of bearing grease the centering belt of the wheel disk on the hub. Do not grease wheel bolts. Replace rusty bolts. Wrap bolts. Lower the car onto the wheels and tighten the bolts crosswise to 110Nm.
15. After completing the bleeding process, fill the reservoir with brake fluid up to the MAX mark and screw on the cap.
Check reliability:
- Are the brake lines secured?
- Is the brake hose fixed in the holder?
- Are the bleed fittings tight?
- Has sufficient brake fluid been added?
- With the engine running, check for leaks. To do this, press the brake pedal with a force of 200-300 N (20-30 kg) within 10 s. The pedal must not loosen. Check all connections for tightness.
16. Check the operation of the brake system on a road with light traffic. To do this, it is necessary to carry out at least one hard braking using the ABS action (felt by the pulsation of the brake pedal).
Attention! Pay close attention to the traffic following you.
Attention! Brake fluid is a hazardous fluid that must never be poured or disposed of with household waste. The local administration should provide information on the nearest brake fluid collection points.