Volkswagen ID.4: Brake servo and brake master cylinder

• Assembly overview - brake servo/brake master cylinder
• Removing and installing brake master cylinder
• Removing and installing brake servo
• Removing and installing brake servo [NX6], right-hand drive vehicles

Assembly overview - brake servo/brake master cylinder

Assembly overview - brake servo/brake master cylinder, left-hand drive vehicles

1. Brake line

• Brake master cylinder/ secondary piston circuit to hydraulic unit
• M12 x 1
• With standard tool: 14 Nm
• With special tools VAS 6854, VAG 1410/7 and VAG 1410/6: 12 Nm

2. Brake line

• Brake master cylinder/ primary piston circuit to hydraulic unit
• M12 x 1
• With standard tool: 14 Nm
• With special tools VAS 6854, VAG 1410/7 and VAG 1410/6: 12 Nm

3. Brake fluid level warning contact -F34-
4. Cap
5. Brake fluid reservoir
6. Bolt

• 4 Nm

7. Brake servo -NX6-

• With brake servo control unit -J539-
• With brake pedal position sender -G100-
• With brake pedal position sender 2 -G836-
• ⇒ Rep. gr. 47; Removing and installing brake servo

8. Gasket for brake servo

• Renew after removing

9. Nut

• Qty. 2
• Renew after removing
• 20 Nm

10. Mounting bracket with brake pedal

• ⇒ Rep. gr. 46; Assembly overview - brake pedal
• ⇒ Rep. gr. 46; Removing and installing mounting bracket

11. Seal

• Renew after removing

12. Brake master cylinder

• ⇒ a2.2 nd installing brake master cylinder"

13. Bolt

• Qty. 2
• Renew after removing
• M8 x 31
• 30 Nm

14. Plug

Assembly overview - brake servo/brake master cylinder, right-hand drive vehicles

1. Cap
2. Brake fluid reservoir
3. Stud

• 4 Nm

4. Brake servo -NX6-

• With brake servo control unit -J539-
• With brake pedal position sender -G100-
• With brake pedal position sender 2 -G836-
• ⇒ Rep. gr. 47; Removing and installing brake servo

5. Gasket for brake servo

• Renew after removing

6. Mounting bracket with brake pedal

• ⇒ Rep. gr. 46; Assembly overview - brake pedal
• ⇒ Rep. gr. 46; Removing and installing mounting bracket

7. Nut

• Qty. 2
• Renew after removing
• 20 Nm

8. Seal

• Renew after removing

9. Brake master cylinder

• ⇒ a2.2 nd installing brake master cylinder"

10. Bolt

• Renew after removing
• M8 x 31
• 30 Nm

11. Brake line

• Brake master cylinder/secondary piston circuit to hydraulic unit
• M12 x 1
• With standard tool: 14 Nm
• With special tools VAS 6854, VAG 1410/7 and VAG 1410/6: 12 Nm

12. Brake line

• Brake master cylinder/primary piston circuit to hydraulic unit
• M12 x 1
•  With standard tool: 14 Nm
• With special tools VAS 6854, VAG 1410/7 and VAG 1410/6: 12 Nm

13. Bolt

• Renew after removing
• M8 x 31
• 30 Nm

14. Plug
15. Brake fluid level warning contact -F34-

Removing and installing brake master cylinder

Special tools and workshop equipment required

• Brake filling and bleeding equipment -VAS 6860-
• Engine bung set -VAS 6122-
• Socket/bit set, 39-piece -VAS 6928-

Removal and installation are described for a left-hand drive vehicle as an example.

Removing

Vehicles with vibration isolation strut

• Remove vibration isolation strut ⇒ General body repairs, exterior; Rep. gr. 50; Lock carrier; Removing and installing vibration isolation strut

All vehicles (continued)

Left-hand drive vehicles

• Remove battery tray ⇒ Electrical system; Rep. gr. 27; Battery; Removing and installing battery tray.

All vehicles (continued)

Right-hand drive vehicles

Remove coolant expansion tank and lay aside with coolant hoses still attached ⇒ Electric rear-wheel drive EIP220 and all-wheel drive EIA200, EIP220; Rep. gr. 19; Cooling system/coolant; Removing and installing coolant expansion tank.

All vehicles (continued)

• Extract as much brake fluid as possible from brake fluid reservoir -1- using brake filling and bleeding equipment -VAS 6860- -A-.

NOTICE

Risk of damage due to corrosion.

• Make sure that no brake fluid gets onto electrical contacts.
• Place sufficient lint-free cleaning cloths in area of brake servo.

• Mark and unscrew brake lines -2- and -3- from brake master cylinder.

• Seal threaded holes in brake master cylinder immediately with M12 sealing plugs (assembly parts).
• Seal brake lines with engine bung set -VAS 6122-.

Note

Fit dust caps from bleeder screws on brake lines as an alternative.

• Disconnect electrical connector -2-.

• Unscrew bolts -4- using socket from Socket set, 39 piece -VAS 6928-.
• Pull out brake master cylinder -3-.

Installing

Install in reverse order of removal, observing the following:

• Make sure that seal and push rod are seated correctly.
• ⇒ Rep. gr. 47; Bleed hydraulic system.
• Carry out function "Basic setting brake servo" using ⇒ Vehicle diagnostic tester ⇒ Rep. gr. 00; Access to diagnoses.

Tightening torques

• ⇒ Rep. gr. 47; Assembly overview - brake servo/brake master cylinder

Removing and installing brake servo

Removing and installing brake servo [NX6], left-hand drive vehicles

Special tools and workshop equipment required

• Brake filling and bleeding equipment -VAS 6860-
• Engine bung set -VAS 6122-
• Hot air blower -VAS 1978/14A-
• Open ring spanner insert, AF 11mm -V.A.G 1410/6-
• Socket/bit set, 39-piece -VAS 6928-
• Torque wrench -VAS 6854-
• Universal joint -V.A.G 1410/7-
• assembly tool -V.A.G 1410/8-

Brake servo -NX6- is referred to hereafter as brake servo.

For sealing plugs (assembly parts), see electronic parts catalogue (ETKA)

Removing

If the brake servo control unit -J539- is renewed, perform the test plan for renewal of the control unit:

• Carry out function "Renew control unit" using ⇒ Vehicle diagnostic tester ⇒ Rep. gr. 00; Access to diagnoses.

Continued

• Remove air intake unit of heater and air conditioning unit ⇒ Heating, air conditioning system; Rep. gr. 87; Front heater and air conditioning unit; Removing and installing air intake unit of heater and air conditioning unit.
• Remove battery tray ⇒ Electrical system; Rep. gr. 27; Battery; Removing and installing battery tray.
• Extract as much brake fluid as possible from brake fluid reservoir -1- using brake filling and bleeding equipment -VAS 6860- -A-.

• Disconnect electrical connector -2- from brake fluid level warning contact -F34- and electrical connector -3- from brake servo -1-.

NOTICE

Risk of damage due to corrosion.

• Make sure that no brake fluid gets onto electrical contacts.
• Place sufficient lint-free cleaning cloths in area of brake servo.

• Mark and unscrew brake lines -2- and -3- from brake master cylinder.

• Seal threaded holes in brake master cylinder immediately with M12 sealing plugs (assembly parts).
• Seal brake lines with engine bung set -VAS 6122-.

Note

Fit dust caps from bleeder screws on brake lines as an alternative.

• ⇒ Rep. gr. 46; Separating brake pedal from and joining to brake servo.
• Unscrew nuts -3- and -4- for brake servo from mounting bracket.

NOTICE

Risk of damage to the plenum chamber bulkhead due to improper separation of the bonded joint.

• Never lever the brake servo off the plenum chamber bulkhead to separate the bonded joint.

• If brake servo gets jammed in holes, loosen nuts -1- and -2- on mounting bracket.
• Pull brake servo off bulkhead, and remove it from vehicle.

Important

• Make sure that the brake lines from brake master cylinder are not bent.

• Remove adhesive residue -arrows- from brake servo -2- and from bulkhead -1-.

• To do so, apply gentle heat from hot air blower -VAS 1978/14A- to the adhesive residue and pull it off.
• Thoroughly clean surfaces.

Installing

Install in reverse order of removal, observing the following:

• Renew gasket between brake servo and bulkhead.
• Insert brake servo, and screw on nuts by hand.
• ⇒ Rep. gr. 46; Separating brake pedal from and joining to brake servo.
• Use assembly tool -V.A.G 1410/8- to fit brake lines.

Important

• Keep brake lines straight when fitting them.

• Tighten brake servo.
• ⇒ Rep. gr. 47; Bleed hydraulic system.

  If

If the brake servo control unit -J539- has been renewed, conclude the test plan for renewal of the control unit:

• Conclude function "Renew control unit" using ⇒ Vehicle diagnostic tester ⇒ Rep. gr. 00; Access to diagnoses.

Continued

Tightening torques

Assembling special tools for tightening brake lines

1. Torque wrench -VAS 6854-
2. Universal joint -V.A.G 1410/7-
3. Open ring spanner insert AF 11 -V.A.G 1410/6-

• ⇒ Rep. gr. 47; Assembly overview - brake servo/brake master cylinder, left-hand drive vehicles
• ⇒ Electrical system; Rep. gr. 27; Battery; Assembly overview - battery
• ⇒ Heater and air conditioning unit; Rep. gr. 87; Front heater and air conditioning unit; Assembly overview - air intake unit of heater and air conditioning unit

Removing and installing brake servo [NX6], right-hand drive vehicles

Special tools and workshop equipment required

• Brake filling and bleeding equipment -VAS 6860-
• Engine bung set -VAS 6122-
• Hot air blower -VAS 1978/14A-
• Open ring spanner insert, AF 11mm -V.A.G 1410/6-
• Socket/bit set, 39-piece -VAS 6928-
• Torque wrench -VAS 6854-
• Universal joint -V.A.G 1410/7-
• assembly tool -V.A.G 1410/8-

Brake servo -NX6- is referred to hereafter as brake servo.

For sealing plugs (assembly parts), see electronic parts catalogue (ETKA)

1. Plugs M10
2. Plugs M12

Removing

If the brake servo control unit -J539- is renewed, perform the test plan for renewal of the control unit:

• Carry out function "Renew control unit" using ⇒ Vehicle diagnostic tester ⇒ Rep. gr. 00; Access to diagnoses.

Continued

• Remove air intake unit of heater and air conditioning unit ⇒ Heating, air conditioning system; Rep. gr. 87; Front heater and air conditioning unit; Removing and installing air intake unit of heater and air conditioning unit.

For vehicles with heat pump valve unit

• Remove heat pump valve unit ⇒ Heating, air conditioning; Rep. gr. 87; Heat pump valve unit; Removing and installing heat pump valve unit.

All vehicles (continued)

• Extract as much brake fluid as possible from brake fluid reservoir -1- using brake filling and bleeding equipment -VAS 6860-.

• Disconnect electrical connector -2- from brake fluid level warning contact -F34- of brake fluid reservoir -1-.

• Remove stud -2-.

• Pull brake fluid reservoir -1- upwards out of brake master cylinder

NOTICE

Risk of damage due to corrosion.

• Make sure that no brake fluid gets onto electrical contacts.
• Place sufficient lint-free cleaning cloths in area of brake servo.

• Unscrew brake lines -2- and -3- from brake master cylinder -1-.

• Seal threaded holes in brake master cylinder immediately with M12 sealing plugs (assembly parts).
• Seal brake lines with engine bung set -VAS 6122-.

Note

Fit dust caps from bleeder screws on brake lines as an alternative.

• ⇒ Rep. gr. 46; Separating brake pedal from and joining to brake servo.
• Unscrew nuts -3- and -4- for brake servo from mounting bracket.

NOTICE

Risk of damage to the plenum chamber bulkhead due to improper separation of the bonded joint.

• Never lever the brake servo off the plenum chamber bulkhead to separate the bonded joint.

• If brake servo gets jammed in holes, loosen nuts -1- and -2- on mounting bracket.

• Disconnect electrical connector -1- from brake servo -2-.

• Remove brake servo from vehicle.

Important

• Make sure that the brake lines from brake master cylinder are not bent.

• Remove adhesive residue -arrows- from brake servo -2- and from bulkhead -1-.

• To do so, apply gentle heat from hot air blower -VAS 1978/14A- to the adhesive residue and pull it off.
• Thoroughly clean surfaces.

Installing

Install in reverse order of removal, observing the following:

• Renew gasket between brake servo and bulkhead.
• Insert brake servo, and screw on nuts by hand.
• ⇒ Rep. gr. 46; Separating brake pedal from and joining to brake servo.

• Use assembly tool -V.A.G 1410/8- to fit brake lines.

Important

• Keep brake lines straight when fitting them.

• Tighten brake servo.
• ⇒ Rep. gr. 47; Bleed hydraulic system.

If the brake servo control unit -J539- has been renewed, conclude the test plan for renewal of the control unit:

• Conclude function "Renew control unit" using ⇒ Vehicle diagnostic tester ⇒ Rep. gr. 00; Access to diagnoses.

Continued

Tightening torques

Assembling special tools for tightening brake lines

1. Torque wrench -VAS 6854-
2. Universal joint -V.A.G 1410/7-
3.  Open ring spanner insert AF 11 -V.A.G 1410/6-

• ⇒ Rep. gr. 47; Assembly overview - brake servo/brake master cylinder, right-hand drive vehicles