We change the fluid in the hydraulic drives of the brakes and clutch every 90,000 km of travel or every three years.
We install the car on an inspection pit or a lift.
We pump the old fluid out of the reservoir with a rubber bulb or a syringe and pour new working fluid into the reservoir.
We bleed the hydraulic drives of the brake system and the clutch until the new fluid (lighter than the old one) begins to come out of the bleed nipples of all the wheel cylinders.
After bleeding the hydraulic drives of the brakes and clutch, we bring the fluid level in the reservoir to normal.
Bleeding the brakes
We remove air from the system with the engine off, first from one circuit and then from the other in the following sequence:
- brake mechanism of the right rear wheel;
- brake mechanism of the left front wheel;
- brake mechanism of the left rear wheel;
- brake mechanism of the right front wheel.
If air enters one of the circuits, it is sufficient to bleed only that circuit and not the entire hydraulic drive.
Before bleeding we check the level of working fluid in the reservoir of the hydraulic drives of the brakes and clutch and, if necessary, top up the fluid.
We clean the bleed nipple of the brake mechanism of the right rear wheel from dirt and remove its protective cap (shown on a 4x4 car).
With a ring spanner or an 8 mm socket we loosen the bleed nipple.
We put a hose on the nipple and immerse its free end in a container partially filled with working fluid.
The assistant must press the brake pedal energetically to the stop 4—5 times and keep it pressed.
With an 8 mm spanner we unscrew the bleed nipple ½—¾ of a turn.
Fluid with air bubbles will then flow out of the hose, and the brake pedal will sink forward.
As soon as the fluid stops flowing out of the hose (the pedal must then reach the stop), we tighten the nipple, and only after that may the assistant release the pedal.
We repeat the bleeding until air bubbles stop appearing in the fluid coming out of the hose.
We remove the hose, wipe the bleed nipple dry and put its protective cap on.
We bleed, as described above, the brake mechanism of the left front wheel, unscrewing the bleed nipple with a 9 mm spanner.
In the same way we bleed the brake mechanisms of the other circuit.
During bleeding it is necessary to monitor the fluid level in the reservoir and, if necessary, top up the fluid.
If, when pressing the brake pedal, we feel its "softness" and increased travel, it means that air remains in the system.
In this case we repeat the bleeding until the pedal becomes "firm" and, when pressed, does not travel more than half the distance to the floor.
If the air cannot be removed, we check the tightness of the connections, pipelines, hoses, the master cylinder and the wheel cylinders.
Bleeding of the clutch hydraulic drive is described in the article — Clutch features of the Renault Duster car.
