Hydraulic Control Unit, Disassembling And Assembling

Fig 1: Hydraulic Control Unit Exploded View

Courtesy of AUDI OF AMERICA, LLC

1. Bolt
   • 5 Nm
2. All Wheel Drive Pump -V415-
   • Removing and installing. Refer to All Wheel Drive Pump -V415-, REMOVING AND INSTALLING .
3. O-Ring
   • Always replace.
4. Adapter
   NOTE:

   The adapter could fall out when removing the All Wheel Drive Pump -V415-.

   Insert the adapter into the recesses in the hydraulic pump before installing the All Wheel Drive Pump -V415-.

5. Hydraulic Pump
   • Consists of a guide ring, the housing and six pistons
   • Assembling. Refer to  23
6. Ball Bearing
   • Can be installed and removed by hand
7. Left Line
   • Tighten the nuts to 30 Nm.
   • Is installed between the hydraulic control unit and the left chamber
   • Tighten both nuts hand-tight when installing
8. O-Ring
   • Always replace.
9. Oil Pressure/Temperature Sensor -G437-
   • 10 Nm
   • Brown connector
   • Removing and installing. Refer to Oil Pressure/Temperature Sensor -G437- OR Oil Pressure/Temperature Sensor 2 -G640-, REMOVING AND INSTALLING .
10. Oil Pressure/Temperature Sensor 2 -G640-
    • 10 Nm
    • Black connector
    • Removing and installing. Refer to Oil Pressure/Temperature Sensor -G437- OR Oil Pressure/Temperature Sensor 2 -G640-, REMOVING AND INSTALLING .
11. All Wheel Drive Clutch Valve 2 -N446-
    • Color: brown
    • Removing and installing. Refer to All Wheel Drive Clutch Valve -N445- OR All Wheel Drive Clutch Valve 2 -N446-, REMOVING AND INSTALLING .
    • Installed position, the connector faces upward toward the Oil Pressure/Temperature Sensor --
      CAUTION:

      Do not interchange with the All Wheel Drive Clutch Valve -N445-.

12. All Wheel Drive Clutch Valve -N445-
    • Color: black
    • Removing and installing. Refer to All Wheel Drive Clutch Valve -N445- OR All Wheel Drive Clutch Valve 2 -N446-, REMOVING AND INSTALLING .
    • Installed position, the connector faces upward toward the Oil Pressure/Temperature Sensor --
      CAUTION:

      Do not interchange with the All Wheel Drive Clutch Valve 2 -N446-.

13. Bolt
    • 2.5 Nm
14. O-Ring
    • Always replace.
    • Mount onto the Clutch Valve --
15. Pressure Spring
    • Insert into the guide -item 16-  HYDRAULIC CONTROL UNIT, DISASSEMBLING AND ASSEMBLING
16. Guide
    • Installation position, large diameter faced the ball -item 17-  HYDRAULIC CONTROL UNIT, DISASSEMBLING AND ASSEMBLING
17. Ball
    • Insert into the guide before installing -item 16-  HYDRAULIC CONTROL UNIT, DISASSEMBLING AND ASSEMBLING
18. Hydraulic Control Unit Housing
    • With centering pins -arrows-
    • The centering pins lock the hydraulic control unit and seal to the final drive housing.
19. Ball
    • Install in the hole in the shuttle valve before installing -item 21-  HYDRAULIC CONTROL UNIT, DISASSEMBLING AND ASSEMBLING
20. O-Ring
    • Always replace.
21. Shuttle Valve
    • 8 Nm
    • Removing and installing. Refer to  23.
22. Gasket
    • With strainer
    • Install on the centering pins in the hydraulic control unit housing
23. Right Line
    • Tighten the nuts to 30 Nm.
    • Is installed between the hydraulic control unit and the right chamber
    • Tighten both nuts hand-tight when installing

Courtesy of AUDI OF AMERICA, LLC

-- Install the six pistons -A- in the housing -B-.

-- Install the guiding ring -C- so that the piston touches the collar -arrow-.

-- Insert the hydraulic pump -1- with the guide ring -2- in the in the hydraulic control unit housing.

Courtesy of AUDI OF AMERICA, LLC

Function Test 

-- Turn the hydraulic pump -1- several times. While doing so pay attention to the following:

• When turning the hydraulic pump must not become hooked or tilted.
• All pistons must be removed and pressed in.

Courtesy of AUDI OF AMERICA, LLC

-- Remove the shuttle valves -A-. Always remove the ball -C- as well.

-- Insert the ball into the hole in the shuttle valve when installing.

-- Install the shuttle valve all the way with a new O-ring -B-.

• The shuttle valve must rest lower than the opposing housing surface -arrow-. If this is not the case, then remove the valve again and adjust the position of the ball.

-- Tighten the shuttle valve to the tightening specification -item 21-  HYDRAULIC CONTROL UNIT, DISASSEMBLING AND ASSEMBLING.