Alternative 1

WARNING: Wear protective gloves and eye protection and use extraction equipment when working with refrigerant. Position the extraction equipment at the service connections on the A/C system and at the discharge outlet on the draining equipment vacuum pump. If refrigerant comes into contact with skin or eyes, it may cause frostbite. Under no circumstances should the engine be started while work on the A/C system is in progress.

NOTE: When converting the A/C system, the usual practice in regard to the high-pressure and low-pressure side when draining and charging refrigerant is disregarded. Carefully follow the colour directions in the method description and on the diagram.

*** FOR ADDITIONAL INFORMATION NOT INCLUDED HERE, REFER TO TSB #08950610, DATED AUGUST, 1995 ***.

Materials
- AKA Mini Force draining and cleaning station for R12
- Refrigerant bottle with two cocks,'gas and liquid
- R12 refrigerant (approx. 10 kg) for, flushing
- 1 red high-pressure hose
- 1 blue low-pressure hose
- Adapter 82 92 849, high-pressure side
- Adapter, oil plug (Sanden compressor) (16)8611824
- Charging equipment for R134a
- R134a Refrigerant

Parts
A spare parts set, part number 74 96 466 , has been developed for converting A/C systems from R12 to R134a. This set contains the following items:
- Dessicant container
- Pressure switch R134a
- Labels
- Service nipples, R134a
- Compressor oil (ester)

Action
1. Check the operation of the A/C system as follows:
- Carry out a performance test. Refer to "Cooling Performance Test, A/C System". Testing and Inspection
- Carry out leak detection procedure
Repair any system faults or damage in conjunction with conversion when the A/C system has been drained of refrigerant.
2. Drain the A/C system of refrigerant. Note the amount of compressor oil that is drained.
3. Repair any damage to the A/C system.
4. Remove the cover over the bulkhead space.
5. Remove the expansion valve's sensitive element and heat it in hot water to max. 50 °C (122 °F).
6. Remove the Schrader valves and Schrader openers in the A/C system and on the equipment so that a free flow is obtained during the flushing process.
7. Connect one end of the blue low-pressure hose to the output on the draining station.
8. Connect the other end of the blue low-pressure hose to the high-pressure side of the compressor.
9. Remove the compressor oil filler plug and fit the adapter supplied in the kit.
10. Connect one end of the red high-pressure hose to the AKA Mini Force (suction).
11. Connect the other end of the red high-pressure hose to the compressor oil charging connection.
12. Open the cocks on the bottle, start the draining station and set the solenoid valve assembly to AUTO. Set the time as follows:
- The solenoid valve should be open a sufficiently long time for the sight glass to fill up at least to the half way mark.
- The solenoid valve should be closed until the sight glass is empty or the pressure has dropped by 1 bar.
13. When the oil is drained, foam and a film of oil will be visible in the flushing unit sight glass.
14. Continue flushing until no more bubbles are visible in the sight glass. Rotate the compressor swash plate a couple of turns during the flushing process.
Close the blue cock on the refrigerant bottle when the A/C system has been purged of oil after about 25 minutes.
15. Drain the A/C system completely of all refrigerant.
16. Drain off the compressor oil from the draining station, note the amount and check that at least 90% of the total volume of oil has been removed.
17. Refit the expansion valve's sensitive element.
18. Change the dessicant container for the one supplied in the set.
19. Fit the three-stage pressure switch supplied in the set to the new dessicant container.
20. Refit the Schrader valves that will be needed for the service valves that are to be fitted.
21. Refit other components that have been removed.
22. Fill the compressor crankcase with the specially developed retrofit compressor oil. This oil is supplied in the spare parts set. 135 ml
23. Refit the oil plug to the compressor
24. Screw the new service valves supplied in the set into place. The larger one is for the high-pressure side and the smaller one for the low-pressure side.
25. Connect up the equipment for R134a. Vacuum pump the A/C system and charge it with R134a refrigerant. 950 grams
26. Remove the existing A/C labels and stick the. "Retrofit" labels in their place. The labels are supplied in the spare parts set.
27. Carry out leak detection and performance testing.