[weq92f]

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You can purchase a vacuum pump, manifold gauge set and a few cans of 134a ( these systems require about 1.8 lbs ) for roughly the same price as a shop will charge you to evacuate and charge the system...about 150 bucks.

Then you get the satisfaction of doing it yourself! Which, BTW, is not difficult...

Recently had to recharge my VA system due to leaky O-ring on the condenser:

Assuming here you're using 12oz cans of 134a rather than a larger container in which case there'd have to be a meter showing how much you've put through the meter. Either that or the pressures would show you when you've reached proper charge...

1)
pull vacuum: attach manifold low/high lines to ports on your truck, attach vacuum pump to yellow charge line, open manifold valves for both high and low side and turn on vacuum pump.

Once the manifold gauges read real close to -30hg or after pump runs for 45 minutes to an hour, close the high/low valves on the manifold and turn the pump off.

2)
allow the system to sit with vacuum for at least a few hours, maybe overnight. Check that the gauges still read the same level of vacuum as above ( -30hg ). If you have vacuum loss, you've got a leak...fix leak and start over...

3)
disconnect vacuum pump, attach freon chuck and freon can, tap freon can, unscrew yellow line from manifold until freon comes out and then tighten it back up ( this purges the air out of the line ).

4)
With the engine NOT running, open the low pressure valve on the manifold -- this releases the freon into the low side of the system. You should see the gauges spike around a bit. Let this sit for a few minutes. Start the engine and turn on the A/C at full cool and fan on high.

5)
At this point and over the next few minutes, the system ~should~ suck in the entire can and your compressor ~should~ engage. You should feel the A/C blowing cooler air than ambient.

If the can doesn't want to empty fully, DO NOT turn it upside down as you DO NOT want to introduce liquid into the yellow charge line. What you can do safely is put the can into a big container of really warm water which will speed the process.

6)
To swap cans, close the manifold valve on the low side ( high side is always closed during charging ), close the can chuck, swap cans, open the can chuck ( pushing freon into the charge line ) then open the low side manifold valve.

Don't overcharge and watch the high side pressure on the manifold so that it doesn't get too high, which might indicate a problem with the install. Same with the low side...

Have a look at an automotive A/C pressure chart as a reference for pressures so you can have some idea of where they should be based on ambient temps.



Hth,

-klb