How to change brake fluid in a BMW
Content
The braking system of each car plays a very important role, as it allows you to ensure the safe use of the car. Since the replacement process is simple, most car enthusiasts prefer to change the brake fluid on BMW vehicles themselves.
Reasons to change brake fluid
The operation of the brake fluid is carried out in a high-temperature mode, sometimes reaching 150 degrees when driving in urban mode. When driving off-road, in addition to the sporty nature of the ride, temperatures can rise even more, which must also be taken into account.
Modern varieties easily withstand temperatures of 200 degrees. They begin to boil only after the temperature reaches 200 degrees.
With timely replacement, this information will be considered theoretical, but the temperature bar will decrease annually, since the liquid has the property of excellent moisture absorption.
This means that the boiling threshold in the presence of at least 2% humidity is no longer 250 degrees, but only 140-150. When boiling, the appearance of air bubbles is noticeable, which disrupts the operation of the brake system.
Replacement period
This parameter is adjusted only by mileage. Most often, it is worth worrying about this problem once every 2-3 years, or 40-50 thousand kilometers. BMW vehicles use DOT4 grade brake fluid.
Changing the brake fluid in the BMW E70
Before starting work, make sure that the general operating instructions for the machine are followed and that the heater baffle is removed.
When carrying out work to replace or repair the following components on the BMW E70, you must strictly follow the operating instructions:
- Master brake cylinder;
- Hydraulic block;
- Parts or tubes that connect them;
- High pressure pump.
After carrying out work on the latter, it is only necessary to bleed the wheel brake circuit in the front of the machine. Before flushing the brake system, it is necessary to turn on the boost pump once through the diagnostic information system.
- Connecting the diagnostic information system BMW;
- Selection of a special valve body pumping function;
- Connect the device to the tank on the master cylinder and turn on the entire system.
At the same time, it is necessary to ensure that the manufacturer's operating instructions are fully observed and that the pressure level does not exceed 2 bar.
Full pumping
One end of the hose is lowered into a container to receive fluid, the other is connected to the coupling head on the right rear wheel. Then the attachment is turned off and the hydraulic drive is pumped until the liquid exits, in which there are no air bubbles. After that, the accessory must be closed. The operation is repeated on all other wheels.
Rear wheels
One end of the hose is connected to the receiving container, the other is put on the fitting of the clamp, after which the fitting is unscrewed. With the help of the diagnostic information system, the brake circuit is pumped until the air bubbles disappear. The fittings are wrapped, and the operations are repeated on the other wheel.
Front wheels
The first three steps here will be identical to pumping the rear wheels. But after pumping with the help of a diagnostic information system, you need to press the pedal 5 times.
There must be no air bubbles in the escaping liquid. After repeating the operation for the second front wheel, it is necessary to disconnect the changer from the reservoir, check the brake fluid level and close the reservoir.
Changing the brake fluid in the BMW E90
To carry out the work, the following equipment will be required:
- Star wrench for removing the drain valve;
- A transparent plastic hose with a diameter of 6 mm, as well as a container where the used brake fluid will drain;
- About a liter of new brake fluid.
When using brake fluid, the prescribed safety regulations must be observed.
The selection of air from the BMW E90 system is usually carried out at the service station, by means of a special device that supplies it to the system at a pressure of 2 bar. This operation can be done independently, for this the assistant must press the brake pedal several times so that excess air is released from the system.
First you need to remove air from the right rear caliper, then from the left rear, right front and left front. During the work, it is necessary to ensure that the volume of liquid does not fall below the required level and top up if necessary.
After closing the tank lid, check the fastening of the brake hoses, the tightness of the air outlet fittings, and also the tightness (with the engine running).
