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
ID.4 2021 ➤
Brake system - Edition 07.2021
– Apply pressure to brake pedal until gauge indicates a pres‐
sure of 50 bar.
Important
•
The pressure must not drop by more than 4 bar during the
test period of 45 seconds. Renew brake master cylinder if
drop in pressure exceeds specification.
Tightening torques
♦ ⇒ Rep. gr. 46; Assembly overview – front brake
3.5
Checking wheel brake cylinder for
leaks
Special tools and workshop equipment required
♦ removal wedge -3409-
Removing
– Lift off dust boot -1- using removal wedge -3409- -2-.
– If brake fluid is found in the dust boot, renew wheel brake
cylinder.
Ensure the dust boot is not damaged when lifting off.
3. Hydraulic system
83
2024 VW ID.4 Owner's Manual
