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Suburban rear AC

95Suburban on Tue March 17, 2009 11:04 AM User is offline

Year: 1995
Make: Chevy
Model: Suburban
Engine Size: 350
Refrigerant Type: R134a
Ambient Temp: 50
Pressure Low: na
Pressure High: na
Country of Origin: United States

I have a 95 suburban with front and rear AC. The rear evaporator apparently had a leak and the prior owner decided to cut the lines going to it. I would like to bypass the rear AC and use the front. Would I cap off both lines at the rear of the truck or loop them together? thank you
Joe

mk378 on Tue March 17, 2009 12:07 PM User is offline

They should be dead-ended. I'd do it near the front so they can't trap oil and take it out of circulation. Or swap in the lines from a single air truck. Are they capped off now, or just cut and left open?

95Suburban on Tue March 17, 2009 12:12 PM User is offline

The lines are crimped over. The system is empty. Hopefully the prior owner had the system evacuated and not just released into the atmosphere. Maybe I would be better off fixing the rear system.

bohica2xo on Tue March 17, 2009 12:45 PM User is offline

You would be better off returning the system to original, both for cooling & resale value.

This will require some effort, but it is not too bad & does not require a bunch of special tools or skills.

Splicing the lines back together can be done with Swagelok connectors. This is a common repair for damaged rear air lines. Since the system is an unknown, a total flush is in order. This means opening the rear evaporator case and removing the TXV to flush the evaporator. I would replace the TXV at this time as well. Really the only additional work for the rear A/C other than splicing the lines. The bulk of the work is in the front system.

B.

-------------------------
"Among the many misdeeds of the British rule in India, history will look upon the act of depriving a whole nation of arms, as the blackest."
~ Mahatma Gandhi, Gandhi, An Autobiography, M. K. Gandhi, page 446.

Cussboy on Thu March 19, 2009 6:35 PM User is offline

bohica2xo - this is a 1995 Suburban, it's real value is about $2500, so whether or not it has rear air (or even air) doesn't do much for its "resale value". I have a 1994 Suburban at that's what it's worth, and same in five more years if it runs. My guess is that, if the rear air really had the leak, then the guy still had a leak after that (such as where he crimped the lines) or the front AC would still be working. I think it's going to be a large expense to get the rear AC working again, high in relation to value of the Sub.

bohica2xo on Fri March 20, 2009 2:55 AM User is offline

Cussboy:

I guess it depends on where you live. Around here a Suburban still brings a good price. 1995 to 1997's are still going for 4k to 5k if they are clean & the A/C works. 1,000 to 1,500 deduct with A/C that is trashed as the OP described. Here in the desert, people will pay a premium for rear A/C.

I recently saw a clean 1988 2wd 2500 Suburban bring $3400.00 Some dealers are asking 6k for 1996's right now. It is really hard to sell that vehicle here with no A/C. The big market is the boat owner with a wife & a pile of rugrats. It becomes the wife's daily driver, so the A/C must work - and rear A/C is a big plus if you have a bunch of kids on board.

What is really hard to find right now around here is a clean, low mileage Excursion with the Powerstroke. Rarely see one for sale here.

B.

-------------------------
"Among the many misdeeds of the British rule in India, history will look upon the act of depriving a whole nation of arms, as the blackest."
~ Mahatma Gandhi, Gandhi, An Autobiography, M. K. Gandhi, page 446.

95Suburban on Fri April 10, 2009 9:24 AM User is offline

I am just going to block off the rear AC and just get the front working. I would like to block it off at the front. What is the best way to block it off? I'm thinking crimping the line over won't be enough. some kind of compression fitting/cap?
thanks,

95Suburban on Fri April 10, 2009 9:24 AM User is offline

I am just going to block off the rear AC and just get the front working. I would like to block it off at the front. What is the best way to block it off? I'm thinking crimping the line over won't be enough. some kind of compression fitting/cap?
thanks,

GM Tech on Fri April 10, 2009 10:55 AM User is offline

Best way I have found is to cut the lines (about 3 inches) behind the fittings where they tee off to rear-- then take them to an aluminum welder- have them pinch the line closed and weld the seam shut- then re-install the newly made "stubbie" back onto the truck. You cannot just pinch it off- or try to solder it-- will not work.. Done about a dozen this way...just have to know a good AL welder....

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The number one A/C diagnostic tool there is- is to know how much refrigerant is in the system- this can only be done by recovering and weighing the refrigerant!!
Just a thought.... 65% of A/C failures in my 3200 car diagnostic database (GM vehicles) are due to loss of refrigerant due to a leak......

95Suburban on Fri April 10, 2009 11:02 AM User is offline

Thanks for the response. I didn't realize there was a fitting near the tee. Is it possible to screw something into the fitting?
thanks
Joe

JACK ADAMS on Fri April 10, 2009 11:15 AM User is offline

Agree with GM Tech, there is a fitting short of where they “T”. You will have to reuse the OEM fitting as they will be a metric thread and have a O-ring seat. You can try to use the Aluminum Braze Rod but a good Tig welder will do the job as well.

Hope this helps and good luck..

brucebotti on Tue May 19, 2009 4:37 PM User is offline

Hi,
My son (95Suburban) started this thread and has now left the old guy to finish. We are definitely looking to block off the rear A/C based on cost and the resale value of the 'Burb. There are fittings for the two lines going to the back, that are located right near the filter/dryer. They came apart, but I have no idea what size / type fittings they are. They are some type of flare / compression fitting. I can't get it apart enough to take it with me to try out different sizes / types. Does anyone have a clue as to what type and size plug I would need for these two lines.
Thanks,
Bruce

GM Tech on Tue May 19, 2009 8:14 PM User is offline

Cut those pipes to the rear with a pipe cutter- 3 inches from the connection! then take them to an aluminum welder- let him pinch the pipes closed and weld the seam shut- then take them back and put them on the truck- rear system is now "stubbied off"

-------------------------
The number one A/C diagnostic tool there is- is to know how much refrigerant is in the system- this can only be done by recovering and weighing the refrigerant!!
Just a thought.... 65% of A/C failures in my 3200 car diagnostic database (GM vehicles) are due to loss of refrigerant due to a leak......

brucebotti on Tue May 19, 2009 9:44 PM User is offline

Quote
Originally posted by: GM Tech
Cut those pipes to the rear with a pipe cutter- 3 inches from the connection! then take them to an aluminum welder- let him pinch the pipes closed and weld the seam shut- then take them back and put them on the truck- rear system is now "stubbied off"

Thanks for the response. I'll have to take a look again, but it looks like it would be a nightmare to remove it and bring to a welder. I'm afraid I'll snap something off in the process. I can't believe that it wouldn't be easier to purchase a plug and seal it that way.
Thanks again,
Bruce

GM Tech on Tue May 19, 2009 11:24 PM User is offline

You are making your own plug!!! a 3 inch long one---works great--no nightmare- just cut it 3 inches from the split with the front-- under hood-- not under the rear...

-------------------------
The number one A/C diagnostic tool there is- is to know how much refrigerant is in the system- this can only be done by recovering and weighing the refrigerant!!
Just a thought.... 65% of A/C failures in my 3200 car diagnostic database (GM vehicles) are due to loss of refrigerant due to a leak......

brucebotti on Wed May 20, 2009 7:08 AM User is offline

Quote
Originally posted by: GM Tech
You are making your own plug!!! a 3 inch long one---works great--no nightmare- just cut it 3 inches from the split with the front-- under hood-- not under the rear...

DUH! I don't know what I was thinking! Sometimes us Senior Citizens suffer from brain fade. I always try to make things harder than they should be!
Thanks again,
Bruce






GM Tech on Wed May 20, 2009 7:45 AM User is offline

If they sold "plugs" I would be first in line........

-------------------------
The number one A/C diagnostic tool there is- is to know how much refrigerant is in the system- this can only be done by recovering and weighing the refrigerant!!
Just a thought.... 65% of A/C failures in my 3200 car diagnostic database (GM vehicles) are due to loss of refrigerant due to a leak......

brucebotti on Sat May 30, 2009 9:03 PM User is offline

Here's an update on the Suburban. I capped off the lines going to the rear; changed the orifice tube and receiver/dryer. I added 2 0z of oil; vacuumed the system and charged it with 2-1/4 #'s of 134. The ambient temperature was 75; the low side was 25; the high side was 150. The air coming out of the vents is about 42 degrees.

My question is: aren't the pressures a little low? I put in 2-1/4 pounds of 134 because that is the spec for a Suburban with front only air. Is it possible that I should put in more 134 because maybe the condensor, etc is larger than a Suburban with front only air? If so, how much should I add.

Thanks for all your help!

Bruce

Chick on Sat May 30, 2009 9:12 PM User is offlineView users profile

There is always some left in the lines, you have to add a couple ounces for that, If you charge with cans, you lose some when you change cans, so adjust for that.. You can add a few more ounces, maybe bring your high side up to 2.2 times ambient at least.. Won't hurt.... At 75 degrees, a high side of 165 to 175 should do it... But watch vent temps, and feel the lines going into and out of the evap, should be about the same temp, with the outlet just slightly colder..Hope this helps.

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Chick
Email: Chick

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Freedoms just another word for nothing left to lose

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