ABS/ESP ITT Mark 20

ABS control module and hydraulic unit, removing and installing

Special tools and equipment




- Brake pedal depressor VAG 1869/2
- Repair kit





1 - Valve dome transportation protection (plastic foam)
2 - M10 sealing plugs for brake lines and threaded holes
3 - M12 sealing plugs for brake lines and threaded holes

After separating the control module from the hydraulic unit always install the valve dome transportation protection on the hydraulic unit.

Warranty claims for hydraulic units on which the valve dome transportation protection was not used, will not be accepted.

Removing






- Remove screws (arrows).

- Remove left-hand cover panel forward.






- If installed, disconnect secondary air intake hose -1- from air cleaner.

- Disconnect air hose -2- from mass air flow sensor.

- Disconnect connector -3- from mass air flow sensor.

- Remove bolts -4- and -5-.

- Remove air cleaner housing.






- Insert brake pedal depressor VAG 1869/2 between brake pedal and driver's seat. Depress the brake pedal by at least 60 mm.

- Connect hose of bleeder bottle to bleeder screws on left front and left rear brake calipers and open bleeder screws.

Note: This dissipates pressure in hydraulic unit.

- Close left front and left rear bleeder screws.

- Do not remove brake pedal depressor VAG 1869/2.






- Release control module connector (arrow -1-) and unplug (arrow -2-).

Note:
- Protect connector housing of control module against escaping brake fluid. Otherwise corroding contacts can cause a breakdown of the system.
- Carefully clean a moist or dirty connector housing with compressed air.

- Lay out sufficient lint-free cloths in area below control module and hydraulic unit.

- Mark brake lines.






- Disconnect brake lines from hydraulic unit to brake master cylinder (arrows) and tie up.

- Disconnect remaining brake lines from hydraulic unit.

WARNING!
Take care not to bend brake lines in the vicinity of the hydraulic unit.

- Seal brake lines and threaded holes with plugs from repair kit.






- Remove bolts on hydraulic unit bracket (arrows) and take out hydraulic unit and control module.

Removing control module from hydraulic unit

- Disconnect connector for hydraulic pump motor from control module.






- Unscrew Torx head bolts -arrows- from control module and detach control module.






- When detaching control module, make sure valve domes of hydraulic unit do not catch on control module solenoids.

- Cover control module solenoids with a lint free cloth.

- Protect components against moisture.

- Install transportation protection for valve domes (enclosed in repair kit) after separating control module and hydraulic unit.

Installing

Install in reverse sequence; note the following points:

Note:
- Only remove sealing plugs on new hydraulic unit when the corresponding brake line is going to be installed.
- If the sealing plugs are removed too soon from the hydraulic unit, brake fluid may escape; it may no longer be possible to fill and bleed the unit properly.

- When assembling control module and hydraulic unit, make sure valve domes of hydraulic unit do not catch on control module solenoids.






Connect lines as previously marked:

A - Secondary piston circuit
B - Primary piston circuit
1 - To right front brake caliper
2 - To left rear brake caliper
3 - To right rear brake caliper
4 - To left front brake caliper

- Install connector on hydraulic pump.

- Bolt ABS control module to bracket.

Note: Do not fully tighten bolts. This facilitates attachment of individual brake lines to hydraulic unit.

- After tightening brake lines, tighten hydraulic unit.

- Bleed brake system

- If a new control module has been installed it must be coded.

- After connecting brake lines to hydraulic unit, perform final control diagnosis.

Note: Final control diagnosis can be used to establish whether line connections have been interchanged.

Tightening torques




1) Replace bolts
2) for M10-connections and M12-connections