Retrofitting

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Conversion from R12 to R134aIf the R12 vehicle air-conditioning system is optional, run it at idle with the A/C blower on high speed for 5 minutes to maximise the amount of oil in the compressor.

1. Recover all R12 refrigerant from the vehicle’s A/C system.
2. Remove the compressor from the vehicle.
3. Remove the compressor oil plug and then drain as much mineral oil as possible from the compressor body.
4. Drain mineral oil from the cylinder head suction and discharge ports while turning the shaft with a socket wrench on the clutch armature retaining nut.
5. Remove the existing R12 receiver-drier or accumulator-drier from the vehicle and discard. Allow as much oil as possible to drain from the A/C hoses.
6. Change any O-rings on the receiver-drier or accumulator-drier joints to approved HNBR
7. O-rings; replace any other O-rings that have been disturbed. 8. Replace the receiver-drier or accumulator-drier with a new R134a compatible one containing XH7 or XH9 desiccant.
8. If a CCOT system is being repaired due to compressor damage, or foreign material is found in the oil drained from the system, this foreign material must be removed from the system. At this time an inline filter should be installed in the liquid line. Allow as much oil as possible to drain from the A/C lines when installing the filter. Change any O-rings disturbed in the installation of the filter to approved HBNR O-rings.
9. Perform any necessary repairs to the compressor or A/C system.
10. Using the original refrigerant oil quantity specification, add SP-20 or SP-10 oil to the compressor (SP-10 for TR, SDV-710, SDB-705, SDB-706 and SDB-709; SP-20 for all other SD compressors).
11. Replace the compressor oil plug O-ring with an HNBR O-ring.
12. Reinstall the compressor oil plug. The plug seat and O-ring must be clean and free of damage. Torque the plug to 11–15 ft lb (15–20 N m, 150–200 kgf cm).
13. Change any seals at the compressor ports to approved HNBR seals.
14. Reinstall the compressor to the A/C system. Evacuate the A/C system for at least 45 minutes to a vacuum of 29 inHg, using R12 equipment, to remove as much R12 as possible from the residual mineral oil.
15. Remove all R12 service equipment and disable the R12 service fittings to prevent any refrigerant other than R134a from being used. Permanently install R134a quick connect service fittings to the A/C system.
16. Connect R134a service hoses and other equipment. Re-evacuate the system for 30 minutes using the R134a equipment.
17. Charge the A/C system with R134a. Generally, about 5% (by weight) less than the R12 charge amount is required. Leak check the system per SAE J1628 procedure.
18. If the A/C system is a CCOT type, which has been repaired due to damage or the discovery of foreign material in the oil drained from the system, run the system for 60 minutes to capture this material in the filter installed in step 9. Recover the refrigerant, remove anddispose of the filter, reconnect the lines, evacuate for at least 45 minutes, and recharge theA/C system. This step should not be necessary for TXV systems, since the drier is fitted with an internal filter.
19. Check the A/C system operating parameters. The system should function correctly within acceptable limits of temperatures and pressures. This will ensure that the correct amount of R134a has been charged.
20. In extreme circumstances when expected cooling performance cannot be achieved and high discharge pressures are experienced, it may be necessary to add more condensingcapacity to the A/C system.An electric fan(s) and/or larger capacity condenser can be used.
21. Replace all R12 compressor labels with retrofit labels per SAE J1660 in order to provide information on the R134a retrofit which has been performed.

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