ID.4 2021 ➤
Brake system - Edition 07.2021
3
Hydraulic system
3.1
General notes on brake fluid
3.1.1
3.1.2
General notes on brake fluid
Changing brake fluid
⇒ Maintenance; Booklet ; Brake and clutch system: Changing
brake fluid
3.2
Bleeding hydraulic system following
standard procedure
Special tools and workshop equipment required
♦ Socket -VAS 6564-
♦ brake filling and bleeding equipment -VAS 6860-
Important
•
A pre-pressure of 2 bar is required on the brake filling and
bleeding equipment -VAS 6860- to bleed ABS hydraulic unit
-N55- .
– Connect brake filling and bleeding equipment -VAS 6860- to
brake fluid reservoir.
– Open bleeder screws in the specified order and bleed brake
calipers and wheel brake cylinders:
1 - Front right brake caliper
2 - Front left brake caliper
3 - Rear right wheel brake cylinder
4 - Rear right wheel brake cylinder
Important
•
The bleeder hose must sit tightly on the bleeder screw so
that no air can enter the brake system.
– Leave bleeder screw of a brake caliper/wheel brake cylinder
open with bleeder breather hose still fitted until brake fluid
discharges free of air bubbles.
Tightening torques
Specified torques for bleeder screws:
♦ ⇒ Rep. gr. 46; Assembly overview – front brake
♦ ⇒ Rep. gr. 46; Assembly overview – brake shoes
3.3
Subsequent bleeding of hydraulic sys‐
tem
Special tools and workshop equipment required
♦ Socket -VAS 6564-
♦ brake filling and bleeding equipment -VAS 6860-
Important
3. Hydraulic system
81
ID.4 2021 ➤
Brake system - Edition 07.2021
•
•
Subsequent bleeding is carried out in connection with exces‐
sive brake pedal travel or so-called “spongy” brakes.
The aid of an additional mechanic is required for the subse‐
quent work steps.
– Connect brake filling and bleeding equipment -VAS 6860- .
– Depress brake pedal firmly and hold.
– Open bleeder screw on brake caliper.
– Fully depress brake pedal.
– Close bleeder screw with pedal held down.
– Release brake pedal slowly.
Important
•
This bleeding sequence must be carried out 5 times per
brake caliper or wheel brake cylinder in the following se‐
quence:
1 - Front right brake caliper
2 - Front left brake caliper
3 - Rear right wheel brake cylinder
4 - Rear right wheel brake cylinder
Important
•
The bleeder hose must sit tightly on the bleeder screw so
that no air can enter the brake system.
– Leave bleeder screw of a brake caliper and wheel brake
cylinder open with bleeder hoses still fitted until brake fluid
discharges free of air bubbles.
A road test must be carried out after the brakes have been bled.
When doing this an ABS regulation must be performed at least
once!
Tightening torques
Specified torques for bleeder screws:
♦ ⇒ Rep. gr. 46; Assembly overview – front brake
♦ ⇒ Rep. gr. 46; Assembly overview – brake shoes
3.4
Testing for leaks
Special tools and workshop equipment required
♦ M10 adapter -V.A.G 1310/6-
♦ tester for brake pressure regulator -V.A.G 1310A-
Prerequisites for testing:
Important
•
Brake system (hydraulic unit, brake hoses, brake lines,
brake calipers and wheel brake cylinders) operating properly
and free of leaks.
– Unscrew bleeder screw at one of front brake calipers.
– Screw M10 adapter -V.A.G 1310/6- into brake caliper in
place of bleeder screw, and tighten it to specified torque of
bleeder screw.
– Connect and bleed tester for brake pressure regulator -
V.A.G 1310A- .
82
Rep. gr.47 - Brakes - hydraulics
2024 VW ID.4 Owner's Manual
