Feon Leak from back of ac compressor

[KDRacing]

When i bought my truck over the winter i never tried the ac to see if it worked and now its gotten pretty hot out and i have been trying to get it working. I checked the pressure with my guage set and high and low read 0... so i replaced the orifice tube whit the sysem was down, evacuated the system and started to recharged it. as i was recharging it i hit 30psi on the low side and the compressor would not kick on (i forced it on by jumping the ac clutch for a second)... I then found a leak coming from the back of the compressor below the lines (i have included a pic) does this mean i have to replace the entire compressor? or is there a way to replace a seal or gasket?


Its leaking from the bolt on the bottom of the bolt pictured. I will try to get a better pic later.

[KDRacing]

so i have figured out that that bolt is a releif valve for the ac compressor... I guess my question now is do i replace it (has it gone bad?) or does it open and close as needed? If it opens and closes as needed why was it open my low side pressure was only about 30-32 and high side was only 30-35... the compressor never kicked on until i jumped it for a second. Im thinking to low side switch may be bad? from what i have read that should be a perfect charge pressure for it to kick on. how would i check the low side switch?

[lug]

30 psi while running on the low side is good. The valve is designed to open around 450 psi. Your high side should be in the mid hundreds to low two hundreds depending on temperature. Replace the valve, evac the system, leak check it and service by weighing the freon going in. The compressor should fire up around 28-30 ounces and settle somewhere near 32 ounces depending on your system. If your truck still has the freon charge placard then you are in luck because that lists the optimum amount for peak efficency.

[KDRacing]

thankyou for the help, I just wasn't sure if that valve should re seal or if it was a one shot deal... or if it was just plain bad.. My local auto parts store didn't have the relief valve and said they couldn't order it I got it on rock auto for around $9 bucks should be here in a few days.

[lug]

Glad to help. I also bought a winter truck and ended up replacing my condensor this past Spring. At least I know exactly the type and amount of freon my truck has in it at time of servicing.

[KDRacing]

So i got the parts in today and installed them after work, no more leak!! My sticker under the hood says the truck should take 2 lbs 10 oz of refrigerant. I went to charge it with my gauges and was only able to get about a 12oz can in, and it wasn't even a full can. Why is my truck not taking the freon? my compressor is kicking on around 38-40 on the low side? and it shuts off around 30... my high side pressure is about 100psi my compressor runs for about 2 seconds at a time then shuts off and is not drawing the refrigerant from the can.

[lug]

The trucks a/c system seems to be working as advertised under a low freon condition. Without boring you with volume, temperature and pressure interactions, what you have is your can pressure is close to the suction pressure resulting in a balance condition. Check the can for a warning about not exceeding a certain temp, usually 110 or 120 F. You need to get the can warm enough to build pressure that is greater than your suction pressure which results in freon being transferred. I use a bucket and hot/warm water to raise the pressure in my can. Take your time and you may have to use a full can instead of your partial one. I use a 20 lb can and volume is on my side unlike the refresh cans. Once you can keep your compressor running you know you're doing good. High pressure center at 80F is 175 psi +-48 psi; 90F is 200 psi +-48 psi; 100F is 250 psi +-48 psi. Aim for the middle and use the tolerance as a guard rail.

[jc82chevyman]

If your compressor is running it should draw the refrigerant out of the can I do this all of the time. Heat does help with exchange process however if your compressor is running and now creating a vacuum you may just have a bad compressor seal.