Retrofit Conversion of A/C System From R12 to R134a

CAUTION: Before commencing work, read and observe "Safety precautions when working on A/C systems". Also read "General information on repair and replacement of A/C system components".

NOTE: The following procedure applies to installation of basic kit, part number 9145660-8 and comprises the basis for the installation of all basic or supplementary kits.

Retrofit conversion of A/C system from R12 to R134a
1. Drain system of refrigerant. Drainage and Recycling, Checking A/C
2. Disconnect/remove:
- Battery ground lead
- Air receiver.
3. Apply releasing agent, part number 1161422-9, to all screwed connections to be undone. Allow agent to act for a few minutes before undoing connection.

NOTE: Never use force to loosen a connection. Heat must never be used.





4. Disconnect and remove:
- ETF/KRU valve at bracket. Remove retaining clip and valve (as applicable).
- Pipes from air receiver inlet and outlet (see note in operation - 6 below).
- Pressostat connector. Remove pressostat and retain for re-use.
- 0-rings (note size). Replace with new 0-rings in kit.
5. Remove air receiver clamp mounting screws.





NOTE: No ETF/KRU valve is installed on earlier cars or when A/C system has been installed as an accessory. In this case, disconnect pipe (arrowed) at firewall. Use supplementary kit 1, part number 9134032-3, when installing.

6. Remove air receiver.
7. Clean all connections which have been disconnected.





8. Plug all open ends to prevent ingress of moisture into system.








NOTE: Observe the orientation of the expansion tube in the pipe.

9. Remove expansion tube located in the evaporator inlet at the firewall (arrowed).
- Clean joint thoroughly.
- Undo nut.
- Pull or work out expansion tube (tube is not screwed in), taking care to ensure that it does not break. Ensure that complete unit is withdrawn.





10. Inspect expansion tube (filter section).
- If filter is badly clogged or if a considerable quantity of metallic particles is present (see illustration), compressor may be in poor condition and in need of replacement.

- As a rule of thumb, if more than 3 or 5 of the expansion tube filter sections are clogged, (illustration B), the compressor oil should be inspected. If the oil is black or badly contaminated, or if the compressor is dry, the unit should be replaced. Illustration A shows an approved expansion tube.

- The original expansion tube should be scrapped after inspection. The kit contains a new expansion tube with the correct orifice size for R134a.

NOTE: 0-ring on compressor inlet and outlet connections must be replaced in all instances. These 0-rings are not included in the kit, but must be ordered separately.





11. If compressor requires to be replaced:
- The new, spare compressor is filled with mineral oil.
- Drain off oil and replace with ester oil. Included in conversion kit 200 ml (0.21 qt).

CAUTION: Oil must not be allowed to enter air receiver when replacing compressor. Fill compressor with oil only through filler opening, not through inlet or outlet connections.








12. Install or replace 0-ring on new expansion tube. Use yellow 0-ring. Compare sizes of new and old 0-rings to ensure that new ring is of correct size.
13. Install lubricated 0-ring in pipe connection in firewall (or on side member).
14. Install expansion tube.
15.Tighten connection nut at evaporator (or on side member) to 12 Nm (9ft lb).





16. Fill air receiver with ester oil through inlet. Oil is included in conversion kit.

NOTE: On earlier cars without piping for ETF/KRU valve. Install pipes from supplementary kit, part number 9134032-3. Finger-tighten connection at air receiver. Use new, lubricated 0-rings. Also connect filler pipe (U-pipe) using new, lubricated 0-ring.





17. Install/connect:
- Air receiver in car.
- New, lubricated 0-rings in connections to evaporator and air receiver outlet
- Pipes to evaporator and air receiver outlet. Finger - tighten.
18. Tighten:
- Pipe between evaporator and air receiver to 27 Nm (20 ft Ib.) at evaporator and to 45 Nm (33 ft Ib.) at air receiver.
- Pipe to air receiver outlet to 45 Nm (33 ft lb).
- Filler pipe (U-pipe) to 16 Nm (12 ft lb).
- Air receiver clamp screws.

NOTE: Compare sizes of new and old 0-rings to ensure that new ring is of correct size.

19. Fit new 0-ring to original pressostat (lubricate with ester oil) and install on new air receiver.
20. Tighten pressostat to 3.5 Nm (2.6 ft lb) (finger-tight).
21. Reconnect pressostat connector.





22. Install new SAE filler valve for R134a.
- Alternative 1: Mount new, lubricated, yellow 0-ring on filler pipe (U-pipe). Install SAE tiller valve. Tighten to 16 Nm (12 ft lb).

- Alternative 2: Mount new, lubricated, yellow 0-ring on filler pipe (U-pipe). Install SAE filler valve and retaining clip (included in conversion kit 9145660-8). Tighten to 16 Nm (l2 ft lb).





23. Vacuum-pump A/C system. Connect R134a drainage/recycling unit. Start vacuum-pump and allow to run for at least 45 minutes.
24. Check that system is maintaining vacuum. Vacuum must not fall by more than one graduation on the gauge within 4 minutes.





25. Additional procedures may be carried out while vacuum-pumping is in progress:
- Fill in the "RETROFIT" sticker before removing the protective and carbon paper.
- Clean the original R12 sticker on the body thoroughly and place the new, light-blue R134a "RETROFIT" over it. The original sticker should be completely covered.
- Attach the round R134a "RETROFIT" to the top of the air receiver.








26. Install blank plugs (included in kit) in unused service valve connections.
- Install two plugs in compressor (unit is not provided with connections in some cases) and one in air receiver (see illustration).
- Use locking fluid, part number 1161351-0, on blanking plug threads.





27. Fill A/C system with refrigerant.
- On completion of vacuum-pumping, fill system with maximum of 200 g (0.21 qt) of refrigerant R134a.
- Use drainage/recycling unit RHS 650 (951 2310), RHS 850 (951 1000) or alternatively, an approved unit.
28. Test for leaks after filling. Use leak detector 9511207, alternatively, an approved detector. Correct leaks as required.
29. Fill system with remaining quantity of refrigerant R134a as specified when system is leak free. For quantity refer to capacities after retrofit from R12 to R134a. Capacity Specifications
30. Test system operation.
Start:
- Engine.
- A/C system.
Check that:
- Compressor starts and runs normally without noise.
- Interior air is cooled. Refer to system performance test.
Testing and Inspection
31.Switch off engine.





32. Test for leaks using leak detector 951 1207, alternatively, an approved detector. Repair leaks (if any).