where do i plug it in at on my '84. it has been retrofited to a R-134. i have a red and blue link and i know that one is low and one is high pressure. anyone know what one is what?

 

The fittings should be different sizes. You shouldn't be able to plug into the high side.

 

On the reciever drier (by the radiator). If the fittings don't fit, you may have to get an adapter (Autozone) Some times when they change over thesystem they don't leave the adapter on.

 

One sure way to tell if you are working with the low or high side lines are that low side lines are larger and usualy insulated than the high side. It works the same way a pump works, the outlet line is larger than the inlet line to keep pressures up. Hope that helps. Always be carful when working with the high side as the pressures are very high. Some people have learned the hard way when the back fed into the can or cylinder and blew them up. Low side pressures around 40 to 45, high side can be near or over 200! depending on outside air temps.

 

Here is a basic drawing....
When I was in the Navy we had saying for everything (mostly electronics)... To easily remember the Parts for a AC system, I came up with this saying: "Can Corvette Owners Ever Accumulate". (Which means to me, I spend way too much money on my car"....)
CAN = Compressor
Corvette = Condensor
Owners = Orifice Tube
Ever = Evaporator
Accumulate = Accumulator
Here is a drawing..... You will see the High and Low sides, and like "MFI" said: The fitting on the high and low side are different if they converted it over. These are quick disconnects for R134, R12 had screw on connectors...

 

thanks, is there someway that i sould let pressure out since i am adding stuff to it?

 

Don't let anything out. If you've replaced a component or otherwise exposed the system to the atmosphere, then you need to hook up a vacuum pump and suck all the air out of it first.

R134 uses quick connect service fittings and they should have been threaded onto the valves when it was converted. The low side fitting is on the Accumulator - big tin can near the radiator and the high is on the smaller line from the Condensor to the Evaporator. If you're using an R134 manifold gage set, it's hoses will only connect with these fittings. The blue (larger fitting) is the low and the red (smaller) is the high. They should snap over the service fittings without letting anything out (or in), though I once bought a pair from a Discounter that leaked - so hopefully you have a decent set.

I'm going to assume you're adding gas and that you have no idea how much is in it (and there isn't anyway to know without sucking it out and weighing it). Hook up a can to the center, yellow hose making sure that both of the valves on the gage set are closed. Momentarily crack the charge line at the gages to let any air out of the line. That way, only gas will get sucked in when you charge it. Start it up and prop the throttle at 1200 to 1500 rpms. Turn the a/c on max and if the compressor is turning on and off (cycling), disconnect the low pressure switch (Evaporator outlet - bigger line on top) and put a paper clip across the harness connector terminals to keep the compressor running. Hopefully, the radiator fan is churning, but if it isn't, I'd jumper it's switch to ground to keep it turning. With the can upside down, open the low side valve ONLY and let it suck in the can while monitoring the high pressure reading. I wouldn't exceed 2.2 to 2.5times the temp of the air at the condensor on your high pressure gage. In other words, if it's 90 degrees out and the air at the condensor is 100 degrees (most Vettes as bottom feeders see a 10 degree difference), stop putting gas in it once you see 220 to 250 psi, 1200 to 1500 rpms, main fan running. Should you happen to see these pressures or higher before you start charging, don't bother with putting anything in it - something else is going on - more than likely a plugged up orifice or some other restriction that's keeping it from cooling.

 

 

thanks

 

Always wear safety goggles (at a minimum) when discharging or recharging an A/C system. Remember, that refrigerant is under high pressure!