A/C High side or low side?
Thread Starter
Burning Brakes
Joined: Mar 2003
Posts: 891
Likes: 165
From: Oswego IL
A/C High side or low side?
I am hoping that someone can help me out. I am planning on doing the 134A conversion to the A/C system on my 74 this weekend. The kit came with new valves, oil, etc.
I want to be sure that I fill to the low pressure and not the high. Can someone confirm which fittng is the high and which one is the low on the stock system.
Thanks,
Ron
I want to be sure that I fill to the low pressure and not the high. Can someone confirm which fittng is the high and which one is the low on the stock system.
Thanks,
Ron
Le Mans Master
Joined: Sep 2000
Posts: 5,635
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From: Orlando Floriduh
Re: A/C High side or low side? (Ron71)
The low side is at the accumulor and anothe at the compressor. the low side is the big line going towards the evaporator. The high side goes forward to the condenser.
Safety Car
Joined: Jul 2002
Posts: 4,269
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From: St. Charles IL
Cruise-In 5-6-7-8-9-11-12 Veteran
A CI-6 Car Show Winner
Re: A/C High side or low side? (Ron71)
Your best bet is to charge liquid at the fitting block where the high pressure switch is located on the liquid line between the condenser coil and the expansion valve. Charging liquid at the compressor can liquid slug it upon startup. Make sure you pull a nice deep vacuum and observe it holds vacuum before charging. Charge the first can to the liquid line (this would be a high side connection, compressor is off at this point) Charge the second can into the accumulator connection slowly with the compressor running. Add a partial 3rd can (if needed) in the same manner.
[Modified by Big Fish, 9:14 PM 6/29/2004]
[Modified by Big Fish, 9:14 PM 6/29/2004]
Thread Starter
Burning Brakes
Joined: Mar 2003
Posts: 891
Likes: 165
From: Oswego IL
Re: A/C High side or low side? (Big Fish)
Thank you all for you your replies and advice. I will give it a shot and hopefully have some A/C again soon. I noticed that the main line has a slice in it, so I am delayed until the new line comes in.
Thanks again,
Ron
Thanks again,
Ron
Instructor
Joined: Dec 2002
Posts: 242
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From: Port Orchard Washington
Re: A/C High side or low side? (Ron71)
The accumulator on a 71 is under the front bumper and has no fitting for charging. An original 71 has two fittings on the hose that connects to the compressor: the one closest to the engine is the low side. The factory manual shows to use these connections when checking pressures. If filling the system, the manual says to use the low pressure fitting on the POA valve. I agree about not filling an empty system at the back of the compressor.
