Bleed brake system with brake filler and bleeder unit VAS 5234 or V.A.G 1869 — VW

Special tools and workshop equipment required

VAS 5234 Brake charging and bleeder unit

or

V.A.G 1869 Brake charging and bleeder unit

V.A.G 1869/2 Brake pedal depressor

Bleed brake system and check for leaks

Place brake pedal depressor V.A.G 1869/2 between driver's seat and brake pedal and load brake pedal as much as possible.

Fit connection of brake charging and bleeder unit VWM CRP 1898017 to threaded piece of brake fluid reservoir.
Connect brake charging and bleeder unitVAS 5234 or V.A.G 1869.
Adjust pressure from 2.0 up to 2.5 kg/cm2 (1.96 to 2.45 bar).
Open bleeding screws in the indicated sequence and bleed brake as follows: To do this evacuate old brake fluid with the appropriate aspirator of the brake charging and bleeder unit.

Bleeding sequence

1 - Rear right wheel cylinder

2 - Rear left wheel cylinder

3 - Wheel cylinder/brake caliper
front right

4 - Wheel cylinder/brake caliper
Front left

Take brake pedal depressor off.
Check brake fluid level in expansion tank and evacuate excessive brake fluid with an aspirator, if necessary.

Changing brake fluid

Note:

Brake fluid is changed because of two reasons:

1stFluid is to old.

2ndRepair work on the brake system:

In the first case the brake fluid must be changed every two years.

When replenishing or extracting brake fluid out of the reservoir the fluid must not come into contact with the paintwork because it will be damaged.

The heat produced during the braking process is not only transmitted to the brake drums or discs but also to the brake fluid via the brake calipers and the brake cylinder.

Brake fluid is hygroscopic, i.e. it attracts moisture from the surrounding air. A higher water content results in a considerable decrease of the boiling point so that gas bubbles may be produced at high temperatures. At very low ambient temperature the brake fluid becomes thick with a higher water content.

When exceeding the boiling point gas bubbles may also be produced e.g. by drives on long and steep slopes at high speed or by an improper towing and a long braking process. Under extremely low temperatures and under certain circumstances it may come air into the brake master cylinder if the brake fluid is too thick. These circumstances appear only under extreme conditions but may lead to damages of the brake system.

The described circumstances show that the fluid in the hydraulic brake system must be changed necessarily, according to the following the regulations, to keep the water content as low as possible.

It is recommended to change the brake fluid every two years.

Prepare brake charging and bleeder unit as for bleeding.

1 -
Evacuate brake fluid with an aspirator as much as possible (when doing this no consumed fluid in the tank is pumped through the brake system).
2 -
Place brake pedal depressor V.A.G 1869/2 between driver's seat and brake pedal and load brake pedal as much as possible.
3 -
Fit connection of brake charging and bleeder unit VWM CRP 1898017 to threaded piece of brake fluid reservoir.
4 -
Let flow new brake fluid into according to the quantity shown in the table. During this process consumed brake fluid is disposed out of the brake system by pumping in new brake fluid.

Wheel cylinder or brake caliper · Specified brake fluid quantity for wheel cylinder or brake caliper
Rear right · 500 cm3
Rear left · 500 cm3
Front right · 500 cm3
Front left · 500 cm3