Conversion Steps A - H

Before proceeding with the conversion to refrigerant R134a, park vehicle inside workshop and allow vehicle to attain workshop temperature (approx. 70° F).





A. Preparation/Testing of the A/C System

B. Testing A/C System for Refrigerant Leaks
1. If A/C system is void of any R12 refrigerant or the compressor will not engage, check refrigerant compressor for binding by rotating A/C compressor by hand.





2. If A/C compressor binding is not present. fill A/C system with fresh recycled refrigerant and perform refrigerant leak test. (Figure 1).

CAUTION:
Observe specifications on Fill Capacity Label.

3. Check for proper operation of A/C system.

Models 124, 129
If parts require replacement, only R134a-type components are to be installed.

Models 107, 126, 201
If the A/C lines, condenser or evaporator require replacement, please continue with "C. Removal of Mineral Oil from A/C System".

Note:
If replacing the A/C compressor, use a compressor designed for refrigerant R134a if available. If a R134a compressor is not available as a spare part, be certain to drain the mineral oil from the new R12 compressor prior to installation.

CAUTION:
In this case, do not refill A/C system with R12, please continue with "D. Replacing Receiver Drier".

C. Removal of Mineral Oil from A/C System
Note:
During the conversion to R134a refrigerant, it is important to remove as much mineral oil from the A/C system as possible.





Steps 1 - 8








Figures 2 and 3

9. Refill recycled R12 once again into A/C system.

10. Operate A/C system again, as in above steps 7-13 for approx. 10 minutes.

CAUTION:
Should the A/C compressor become noisy, stop engine and continue with "D. Replacing Receiver Drier.

11. Using air conditioning service equipment, evacuate the R12 at high. and low-pressure sides (A, Figure 2 and B, Figure 3) of A/C system for 45 minutes.

Note:
A/C service equipment should be able to pull at least 29.2" of vacuum.

CAUTION:
At this point, R12 is not be used in A/C system again.

D. Replacing Receiver/Drier
Please see SMS, Repair Instructions, Job No 83-540.





E. Installation of Service Valves

CAUTION:
Prior to the installation of the angled service valve (Figure 6) or adapter hose (4, Figure 7) the existing Schrader valve core (arrow, Figure 4) located in A/C line must be removed.





1. Depending on accessibility, select the appropriate service valves (Figure 5 and Figure 6) or adapter hose (4, Figure 7) and install on the low- and high-pressure side of the A/C system (A, Figure 2 and C, Figure 4).

Tightening torque: 7.5 + 0.5 N-m

CAUTION:
The threads of the service valves are treated with a chemical thread locker, which becomes effective after 15 minutes. When installing the hose, make certain that the hose and service valve do not come in contact with any moving parts. Removal of the service valve beyond this time span is not possible.

Note:
The adapter hose (4, Figure 7) is designed for use in areas with difficult access to the service valve. Additionally, depending on the application (high- or low-pressure side), the standard service valve with respective protective cap (Figure 5) must be installed on the open end of the adapter hose (circle, Figure 7).

CAUTION
Be careful not to mix up low-pressure (blue) and high-pressure (red) service valve caps when installing the service valves into A/C lines.

F. Filling A/C System with R134a Refrigerant
1. Evacuate AC system using air conditioning service equipment.
2. Fill AC compressor with PAG oil, note fill capacity in image.
3. Fill AC system with refrigerant R134a, note fill capacity in image.
4. Run engine at idle speed for approx. 3 minutes.





G. Affixing R134a Fill Label





1. Using a permanent marking pen, note fill capacities of R134a refrigerant and PAG oil in the appropriate boxes of the R134a Fill Label, along with the conversion date (Figure 8).
2. Affix R134a Fill Capacity Label over the existing label.

H. Performing Final Function Test of A/C System.
1. Perform final function and leak test of the A/C system to verify proper function of the entire A/C system.




Parts Information:

Time Allowance Information:
Recommended labor times to convert A/C refrigerant system from R12 to R134a:
1. A/C system with R12 refrigerant-Convert to R134a = 1.8 hrs.
2. A/C system with R12 refrigerant-Convert to R134a = 1.2 hrs (with compressor replacement).

In Case of Warranty:
Please use damage code and operation number of the damage causing part.
Please refer to the latest Time Guide Edition, starting with edition No. 22 upon release.