Monday, November 17, 2014

How to Replace an A C Service Port

Years ago in the days of R12 rigerant, when an air-conditioning service port went bad on your automobile, a Schrader valve could simply be serviced by itself. In todays 134A world, things have gotten a bit more complicated and costly. You cannot just replace the inside of a Schrader valve; now you have to replace the entire line where the port is located.

Instructions

    1

    Connect either the high side or low side hose on an A/C servicing station to the appropriate service port. Do not connect a line from the air-conditioning servicing station to the defective port. Evacuate the R134a rigerant into the rigerant tank on the air-conditioning station by turning on the evacuation pump and running it until all the rigerant has left the system.

    2

    Disconnect both ends of the line with the defective service port and remove the line. Cover the connections on the A/C system with clean shop rags to prevent dirt and moisture from getting into the A/C system.

    3

    Inspect the connections for discoloration. If the connections are clean and slightly oily there are probably no other problems that caused the service port to go bad. Blackened connections could be a sign of internal compressor problems. Investigate further and perform any necessary repairs.

    4

    Connect the ends of the replacement line with the built-in service port just as the old line was connected. Ensure that any O-rings or seals at the ends of the lines are replaced and lubricated with mineral oil before the new line is installed.

    5

    Connect the other hose from the A/C servicing station to the replacement port. Start the evacuation pump and run it for 15 to 20 minutes to ensure that all the moisture has boiled out of the A/C system. Note the vacuum readout on the A/C station. Allow the system to sit for 10 minutes. Recheck the A/C stations vacuum readout to ensure there is no loss in vacuum. A loss indicates a leak in the system, probably in one of the two replacement line connections. Repair as needed.

    6

    Remove the service hose from the high side service port and start the vehicle. Turn the climate control switch to "Maximum." Set the machine to charge the system with R134a and the correct amount of compressor oil through the low side service valve. When enough rigerant is in the system, the air-conditioning compressor will start and draw the rest of the desired amount of rigerant and oil into the system. Remove the low side hose, completing the replacement of the service port.


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