AC Vacuum Pump and Oil

[Dynomite]

Has anyone used an AC Vacuum pump (gauges) and oil in the case of a break in the AC connections? How do you do it?

[VetteVet]

Cliff,

I'm not understanding your question. Are you asking how to vacuum(evacuate) the freon system prior to charging?

If so, detailed instructions are available in the FSM. Pay careful attention to the type and quantities of oil. The FSM lists how much oil should be present in each of the components. There are variables depending on whether you are changing any components, but the FSM explains it pretty well.

Feel free to PM me if you have any questions. I do marine AC systems on the job and do all of my own AC work on my vehicles.

Jep

[Dynomite]

Originally Posted by VetteVet

Cliff,

I'm not understanding your question. Are you asking how to vacuum(evacuate) the freon system prior to charging? Yes.....in the case where you lost it all in a break.

If so, detailed instructions are available in the FSM. Pay careful attention to the type and quantities of oil. The FSM lists how much oil should be present in each of the components. There are variables depending on whether you are changing any components, but the FSM explains it pretty well.

Feel free to PM me if you have any questions. I do marine AC systems on the job and do all of my own AC work on my vehicles.

Jep

Jep......You are definitely DAMAN....appreciate that. I am thinking I can buy a vacuum pump at Harbor Freight or Sears for a couple hundred and set it up on my system for 45 minutes and then re-install Freon 12. I know I lost some oil and need to replace some oil.

Also there is some desiccant of sorts that has to be changed?

That is what I want to do

Maybe I am smoking dope.....
But then again......I will try anything once.

Darn line broke at Evaporator when I pulled the engine......I got new evaporator (I guess it is the evaporator) and now need a charge.

Oh...almost forgot.... 91' ZR1 is up and running again after some "secret" changes....Extremely smooth idle and ....and...well...you know the rest of the story when it comes to a nicely tuned, ported, cammed, Open Exhaust LT5. I pulled the engine with Headers installed and put engine back in Z same way.....except for the AC issue

[VetteVet]

Cliff,

Vacuum for an hour, then shut gauge manifold valves, turn off vacuum pump and monitor vacuum in system for evidence of any leaks. If none, you're set to charge with the amount of R-12 listed in the FSM. When you connect the can, make sure that you have the can upright and then loosen the fill hose at the manifold to purge the air, then retighten it. The can has to be upright to ensure that you get vapor, not liquid. Charge to the low(suction) side with can inverted until you cannot get any more Freon to flow into the system, then return can to upright position, start engine, leave doors open, switch climate control to auto and set to lowest temp setting. If you don't have enough pressure in the system for the A/c compressor to kick on, disconnect the pressure cycling switch and jump the two wires to energize the clutch. Add remaining Freon to the low side with can in upright position. You don't want any liquid Freon hitting the compressor, as that will damage it. Remember to shut the low side valve when changing cans and also re-purge the fill line. It doesn't take very much air/moisture in the system to seriously degrade performance.

The FSM lays it out very nicely. Shoot me a PM if you have any questions.

Jep

[Dynomite]

Originally Posted by VetteVet

Cliff,

Vacuum for an hour, then shut gauge manifold valves, turn off vacuum pump and monitor vacuum in system for evidence of any leaks. If none, you're set to charge with the amount of R-12 listed in the FSM. When you connect the can, make sure that you have the can upright and then loosen the fill hose at the manifold to purge the air, then retighten it. The can has to be upright to ensure that you get vapor, not liquid. Charge to the low(suction) side with can inverted until you cannot get any more Freon to flow into the system, then return can to upright position, start engine, leave doors open, switch climate control to auto and set to lowest temp setting. If you don't have enough pressure in the system for the A/c compressor to kick on, disconnect the pressure cycling switch and jump the two wires to energize the clutch. Add remaining Freon to the low side with can in upright position. You don't want any liquid Freon hitting the compressor, as that will damage it. Remember to shut the low side valve when changing cans and also re-purge the fill line. It doesn't take very much air/moisture in the system to seriously degrade performance.

The FSM lays it out very nicely. Shoot me a PM if you have any questions.

Jep

Jep:
Thank you thank you
I will think, study, and think some more and maybe PM you if I have questions......I am not sure about the oil yet but did not loose very much oil as my understanding most of the oil resides in the compressor. I will give it a try....and thanks again.

I am sure anyone who has pulled an LT5 moving the AC compressor out of the way over to the drivers side has prolly done what I did once or twice....pulled too much on the AC line attached to the evaporator

Cliff

[4-cam]

Also If the system has been opened for any length of time, replace the accumulator/Drier to make sure you have a clean dry system. Cheap insurance as these compressors are expensive.

http://www.rockauto.com/catalog/more...995&cc=1041297

[VetteVet]

Originally Posted by 4-cam

Also If the system has been opened for any length of time, replace the accumulator/Drier to make sure you have a clean dry system. Cheap insurance as these compressors are expensive.

http://www.rockauto.com/catalog/more...995&cc=1041297

Thanks for the catch, 4-CAM. I had that in my original write-up but brain farted and lost it all. I omitted it when re-typing everything.

Jep

[Dynomite]

Originally Posted by 4-cam

Also If the system has been opened for any length of time, replace the accumulator/Drier to make sure you have a clean dry system. Cheap insurance as these compressors are expensive.

http://www.rockauto.com/catalog/more...995&cc=1041297

Thank you.....appreciate that informaton and source
Also at Oreilly Auto Parts Murray AC Accumulator/Drier for $43 (for a 91 ZR1)

Or Eckler's Corvette has the Air Conditioning Receiver Drier for $25 plus shipping.

And thanks again Jep for the technical information.....appreciate it

[VetteVet]

Originally Posted by Dynomite

And thanks again Jep for the technical information.....appreciate it

Cliff,

Glad to be of assistance. It's kind of unusual seeing you asking for advice. You're usually the one generously dishing it out.

Jep

[HAWAIIZR-1]

Thanks guys for all the technical info related to A/C. Reading all of this made me decide to leave my A/C service to a professional. I have a new compressor waiting to be installed as well as the drier/accumulator, orifice tube, etc. and will wait until I get back to the US. There is a good shop in Hawaii that identified I had leak from my compressor with some dye in freon before shipping the car in early 2011 that I have not addressed since and will use them when I return. My understanding is I also need some special oil for the brand new compressor according to the supplier.

Craig