Attention: Bleed the brake system while wearing goggles. If brake fluid accidentally gets into your eyes, rinse immediately with plenty of water and seek medical attention!
1. Bleeding the hydraulic system is carried out in order to remove air from it that enters the path when servicing the brake mechanisms, replacing hydraulic lines or GTZ, as well as when lowering below the minimum allowable value of the liquid level in the master cylinder reservoir.
2. Depress the foot brake pedal several times with the engine off to release the residual vacuum in the vacuum brake booster.
3. All models covered in this manual are equipped with ABS as standard. For high-quality and guaranteed pumping of the hydraulic drive, as well as for the clutch drive (see Chapter 6, Section 4), a special bleed kit must be used - carefully read the instructions for its use before starting work. Remove the brake fluid reservoir cap and replace it with an appropriate bleed adapter. To prevent air from entering the brake path, the free end of the hose must be immersed in a container with brake fluid (see resist. illustration) - do not forget about the need to monitor the fluid level in the master cylinder reservoir (the level must not fall below the MINI mark).
4. Upon completion of pumping, add fresh brake fluid to the GTZ reservoir, bringing its level back to normal.
5. Check up efficiency of functioning of brakes. When depressing the pedal, it should provide firm resistance - a feeling of softness of its stroke indicates the presence of air in the hydraulic circuits and the need to repeat the pumping procedure.
Attention: Never start using the car without being absolutely sure that the brake system is working properly!
Emergency method of pumping - the help of an assistant is required
6. In some cases, when the bleeding kit is not available, but it is necessary to continue the trip, if air enters the hydraulic path of the service brake drive, you can use the method below.
Attention: On models equipped with ABS, this method does not give a 100% guarantee of complete removal of air from the system - be especially careful when continuing to drive!
7. If air has entered the system due to a drop in the liquid level in the GTZ tank, or when the brake lines are disconnected from the GTZ, the brake mechanisms of all four wheels must be pumped. When disconnecting the Lines from any of the calipers / wheel cylinders, it will be enough to pump only this particular brake mechanism.
8. If the brake line was disconnected from the fitting located between the GTZ and one of the brake mechanisms, only this part of the brake circuit is pumped.
9. Before starting the procedure, check the level of brake fluid in the reservoir and, if necessary, bring it to the mark «MAX».
Note: Remember to check the fluid level in the tank regularly while pumping. An excessive drop in the level is fraught with air entering the GTZ, which will nullify all the efforts made and entail the need to pump the entire brake system.
10. Enlist the help of an assistant, prepare a supply of fresh brake fluid, a transparent container partially filled with brake fluid, a piece of plastic hose that fits tightly over the bleed valve, and a suitable open-end / ring wrench to release / tighten the valve.
11. Remove the dust cap and slightly loosen the bleed valve (see resist. illustration) rear right wheel brake, then re-tighten it so that it releases quickly and easily during the procedure.
12. Pull a suitable plastic or rubber hose onto the valve, lower the other end into a transparent vessel partially filled with clean brake fluid (see illustration 3.3). The end of the hose must be completely immersed in the liquid.
13. Ask an assistant to slowly squeeze the foot brake pedal several times, thereby raising the pressure in the system.
14. With the brake pedal fixed in the lower position, slightly open the bleed valve so that brake fluid begins to be forced out of it. Watch for fluid exiting the hose. After a couple of seconds, when the pressure weakens, close the valve and allow the assistant to release the pedal.
15. Repeat the procedures of the last two paragraphs until fluid free from air bubbles begins to flow from the valve, then go to the brake mechanism of the left rear wheel. In the same manner, bleed this mechanism, then the mechanisms of the right front and finally the left front wheels.
Attention: Always make sure that the liquid level in the GTZ reservoir does not fall too low, if necessary, make the appropriate adjustment!
16. Never add used brake fluid to the reservoir - it is highly hygroscopic and absorbs a lot of moisture over time, which leads to a drop in its boiling point and, as a result, to a decrease in braking efficiency. In addition, the presence of moisture in the hydraulic system contributes to the accelerated aging of the material of flexible brake hoses.
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