This procedure covers the replacement of air supply lines for the AWD system's pneumatic actuators on the 2016-2024 Hyundai Tucson 2.5L I4 AWD.

Warnings

Tools required

Parts

• AWD air supply line assembly × 1 — Use OEM specification
• Air line mounting clips × 4 — Use OEM specification
• Push-to-connect fittings (if damaged) × 2 — Use OEM specification

Preparation

1. Park vehicle on level surface and engage parking brake
2. Allow engine and exhaust system to cool completely if recently driven
3. Raise rear of vehicle and support securely on jack stands at rear subframe points
4. Remove rear wheels to access underside components
5. Disconnect negative battery terminal and wait 3 minutes before proceeding

Procedure

1. 1

   Remove rear wheel and locate air line routing
   With vehicle raised and supported, trace the air line from the AWD coupling unit on the rear differential forward along the underbody. Note the location of all mounting clips and routing points. The line typically runs along the driver side frame rail.
2. 2

   Release air pressure from system
   Locate the air supply fitting at the AWD coupling on the rear differential. Press the release collar on the push-to-connect fitting while gently pulling the line to disconnect. Allow any residual air pressure to escape completely. You may hear a brief hissing sound.
   ⚠Keep face and hands clear of fitting opening when releasing pressure.
3. 3

   Disconnect air line at front connection point
   Trace the air line forward to the connection point near the transfer case or front frame rail. Press the release collar on the push-to-connect fitting and pull the line free. Inspect both fittings for damage or excessive wear.
4. 4

   Remove mounting clips and brackets
   Remove all mounting clips securing the air line to the underbody. These are typically 10mm bolts or push-type clips. Count and note the location of each clip for reinstallation. Use trim removal tools for push clips to avoid breaking them.
   Torque spec

   Mounting Bolts27 Nm (20 lb-ft)
5. 5

   Extract old air line from vehicle
   Carefully pull the air line free from its routing path, taking care not to snag it on any sharp edges or exhaust components. Inspect the routing path and clean any debris or corrosion from mounting points using a wire brush.
6. 6

   Inspect connection points and clean fittings
   Examine both push-to-connect fittings on the vehicle for dirt, corrosion, or damage. Clean the fitting ports with compressed air or a shop vacuum. Inspect O-rings inside fittings and replace fittings if O-rings are torn or missing.
7. 7

   Route new air line along underbody
   Begin routing the new air line from the rear differential forward, following the exact path of the original line. Ensure the line does not contact exhaust components, sharp edges, or moving suspension parts. Maintain factory bends and routing to prevent kinks.
   ⚠Do not stretch or kink the air line. Maintain at least 2 inches clearance from exhaust system.
8. 8

   Install mounting clips and secure line
   Install all mounting clips and brackets in their original locations. For bolted clips, torque mounting bolts to specification. For push clips, ensure they are fully seated with an audible click. Verify the line is held securely without excessive tension.
   Torque spec

   Mounting Bolts27 Nm (20 lb-ft)
9. 9

   Connect air line at rear differential
   Push the air line firmly into the push-to-connect fitting at the AWD coupling unit until you feel and hear a click. Gently tug on the line to verify it is locked in place. The line should not pull free with moderate force.
10. 10

    Connect air line at front connection point
    Push the front end of the air line firmly into the push-to-connect fitting at the transfer case or frame rail connection until it clicks into place. Tug gently to confirm secure connection. Inspect entire line routing one final time.
11. 11

    Reinstall wheels and lower vehicle
    Reinstall rear wheels and hand-tighten lug nuts in a star pattern. Lower vehicle to ground and torque lug nuts to specification in a star pattern. Reconnect negative battery terminal.
    Torque spec

    Wheel Lug Nuts136 Nm (100 lb-ft)

Reassembly

1. Ensure all mounting clips are securely fastened and air line has proper clearance from all components
2. Verify air line connections are fully seated at both ends with no visible gaps
3. Double-check that air line does not contact exhaust system or moving suspension parts

Verification

• Start engine and allow to idle for 2 minutes while monitoring for air leaks at connections
• Test drive vehicle in various conditions including turns and acceleration to verify AWD engagement
• Check for AWD warning lights on instrument cluster - light may illuminate briefly then extinguish after system self-test
• Listen for unusual hissing sounds from rear undercarriage indicating air leaks
• Perform visual inspection under vehicle after test drive to confirm air line remains properly routed and secured

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