Expansion Block/Orifice Tube: Service and Repair

EXPANSION (ORIFICE) TUBE REPLACEMENT

REMOVAL PROCEDURE




1. Recover the refrigerant. Refer to Refrigerant Recovery and Recharging. Service and Repair
2. Remove the front evaporator tube to rear evaporator tube retaining bolt.

IMPORTANT: Cap or tape the open rear evaporator tube immediately to prevent contamination.

3. Disconnect the front evaporator tube from the rear evaporator tube, discard the O-ring.

IMPORTANT: Cap or tape the open front evaporator tube immediately.




4. Using needle nose pliers, CAREFULLY grasp the edge of the expansion (orifice) tube without touching the filter screen and pull to remove the tube.




5. Inspect the expansion (orifice) tube for the following conditions and clean or replace with a new tube as indicated:
^ Broken plastic frame; replace tube
^ Filter screen (1,2) torn, damaged or plugged with fine gritty material; replace tube
^ Brass orifice tube (3) damaged or plugged; replace tube
^ Filter screen (1) coated with metal chips, flakes or slivers; coating may be removed with low pressure shop air and reused if cleaned satisfactorily
If reusing the tube, install a new O-ring (4)

INSTALLATION PROCEDURE




1. Remove the cap or tape from the front evaporator tube.
2. Using needle nose pliers, CAREFULLY grasp the edge of the expansion (orifice) tube (long filter screen inlet side of tube) without touching the filter screen and insert the tube (short filter screen outlet side first) fully into the front evaporator tube.




3. Remove the cap or tape from the rear evaporator tube.
4. Using a lint-free clean, dry cloth, carefully clean the sealing surfaces of the rear evaporator tube and the front evaporator tube.
5. Lightly coat the O-ring seal (1) with mineral base 525 viscosity refrigerant oil.

IMPORTANT: DO NOT allow any of the mineral base 525 viscosity refrigerant oil on the O-ring to enter the refrigerant system.

6. Carefully slide the new O-ring seal (1) onto the front evaporator tube until seated.

Leave a light coating of the refrigerant oil to remain on the front evaporator tube in the area indicated (2) ONLY.




7. Install the front evaporator tube to the rear evaporator tube.

NOTE: Refer to Fastener Notice in Service Precautions.

8. Install the front evaporator tube to rear evaporator tube retaining bolt.

Tighten
Tighten the evaporator retaining bolt to 25 N.m (18 lb ft).

9. Evacuate and charge the refrigerant system. Refer to Refrigerant Recovery and Recharging. Service and Repair
10. Check the evaporator tube joints for leaks. Refer to Leak Testing.Leak Testing