Damage to A/C parts that have been sitting

[kgroombr]

I am assembling my A/C system that has been sitting for some time. I have the equipment to clean the components as I install them, but was reading that there is acid that forms in the A/C system from exposure to air.

I didn't know this when disassembling, so I don't know if there is any damage from sitting on the shelf. Anybody have some insight on this? Googling didn't help much, but not sure if my search terms were good.

Thanks,
Ken

[HI WINDING MONZA]

Ask these guys ,they will help..........

http://acsource.net/acforum/viewforum.p ... 79903bc743

Doug in P.R.

[kgroombr]

Ask these guys ,they will help..........

Doug in P.R.

You rock! Exactly what I was looking for. I have been using keyword searches to search existing posts and pretty much validated that I should be OK. From what I have found some slight corrosion happens from sitting, but neglegible. It is the continued cycling of moisture in the system that creates tons of acid that really does the damage.

Thanks,
Ken

[firebird77clone]

You can shoot lacquer thinner through the various components to wash them clean. Not the compressor though.

[zeke]

You can shoot lacquer thinner through the various components to wash them clean. Not the compressor though.

That's what I did.

New o-rings, drier and oriface is a good plan also.

[kgroombr]

Thanks for the info.

I actually purchased a kit from Amazon for about $70 that includes the flush (like this one "ATD Tools 3545", but the one I got is no longer listed as it looked the same and was half the price with a five star review) tool and a gallon of flush (FJC 2128) specifically for A/C components.

Was originally looking for the o-rings by GM part number with no avail, then found out they are standard sizes and got a kit, also from Amazon, with more o-rings than I will ever need for about $5.

Ken

[firebird77clone]

O rings material must be selected based on refrigerant use.

I think the refrigerant rates o rings are green, not black.

[HI WINDING MONZA]

Green is for 134a line fittings , but the compressor line gaskets are still black and aluminum . ( but different material than for R12)

Doug in P.R.

[HI WINDING MONZA]

Dont forget to change the mineral oil in the compressor to Pag oil ........... ( it still may leak refrigerant due to the rubber seals, you should change the compressor to one with 134a friendly seals).

I used a guy on Ebay in Texas that sold me the complete kit for my 90 Silverado ( compressor, drier, orings, orfice)

I recomended him to member "skidive" also.

Doug in P.R.

[kgroombr]

Thanks Doug in P.R.

My o-ring kit is all the new green style compatible with R134a. Didn't know anything about Pag oil. I looked that up and yep, I will have to get some of that too. Right now I am just getting everything together before I get started.

Looks like I may have to send my POA valve off to be rebuilt to support R134a. Found a place that does it, but it is a couple hundred bucks, but probably better do it so that it works well.

Thanks,
Ken

[mahoy78spyder]

This has been a great thread in a short amount of time... I've learned a lot. Would recommend we archive this in our 'best of' thread....

[MonzaRacer]

OK, want REAL honest proper service procedures.
Here we go.
First of all UNLESS you have a hose or other part with KNOWN black death and you must try to save it DO NOT, I REPEAT, DO NOT USE ACETONE, LACQUER THINNER OR OTHER SOLVENT OF THESE TYPES IN AC SYSTEMS.
There are only two things that WONT leave contaminants to come back and haunt you later on, plain old methanol air brake antifreeze with no conditioners or additives, or straight anhydrous ethanol.
Basically if you have black death its from mixing mineral oil and pag/ester oils and r2/r134a/other refrigerants.
There is a lot of GARBAGE out there on AC service, of which 99% are bunk, crap and/or guaranteed too get you sued by the shop that recharges your system and gets a few hundred or thousand dollars of refrigerant CONTAMINATED by your system.
Drop ins, R134a, R12, etc. ANY and ALL of these used in an automotive system MUST have dedicated fittings, gauges and hoses for them. You mix r12 and r134a and it can become explosive, especially if contaminated with other chemicals.

So, best beginning "inspection flush" plain old methanol air brake antifreeze, follow with a small amount of Dura142 flush from NAPA.
For systems that HAVE had R12 in them use Ester 100 oil for conversion OR look for ROC oil. PAG and mineral oil DO NOT palay nice together and make th black death and acids mentioned by some.
Ester 100 conversion oil is even better as it has some conditioners to "help" the old and new oil play nice together.
For orifice tube systems best unit too use are automatic adjusting units.
207325 for under 105F and if you live in Phoenix or some other desperately hot place look for a 207327. Those are NAPA numbers for reference.
Locating an adjustable cycling switch helps as you really want it cycling off at around 20 psi on low side.
Operating pressures on CCOT/AAOT systems SHOULD run in around 28-32 psi ish on low side and NOT pull down to cycle switch pressures.
Driers need to have XH5 or XH7 desiccant in them the former has pretty much been phased out, and XH7 is the normal R134a desiccant.
Proper air flow over condenser is CRITICAL. Most older systems MIGHT have some issues handling R134a but with the AAOT should help by unloading compressor at cruise but keeping low speed performance acceptable.
All wiring should have a good 30amp or larger relay running the compressor and the cycling switch/system switch operating the relay.
All the H body systems with A6 compressor use AT LEAST 10 to 12 oz of oil in compressor alone, figure aluminum accumulators will take around 3 oz, evap/cond 1 oz each and 2 oz for hoses. R4 or similar compressors will use around 1 1/2 to 2 oz but it doesnt stay very long but add it in and crank compressor over many times.
OTHER GM and aftermarket compressors will have a specific amount, try to follow that guide.
ONLY use what your compressor calls for if other than stated here, for warranty purposes. Supposedly after 2002 GM has went to PAG46 on most cars, but if using PAG in an R4 or A6 style compressors use PAG 150, which used to be the fleet wide go to lubricant.
also made is a PAG 100 but thats other brands spec oil.
Basically find out what compressor you have and run that if you dont know PAG 150 or POE 100(Ester).
ROC oil
Cliplight 51105 Universal Application ROC Oil for A/C - 500 mL Found here: http://www.toolplanet.com/product/Clipl ... ries-parts
Will work for most any system regardless of the refrigerant.
Awesome product, wish OEMs would run it standard. Most of your dyes are in ROC oil.

I generally charge by pressures if converting , the old rule on conversions was 80% but has been changed over to use same capacity.
Biggest issue has been that many systems converted STILL cycled too much needing more than listed.
I learned AC by charging by pressures.
Now some systems use a Thermal Expansion valve, absolutely awesome as it keeps evaporator from freezing , as long as its functional as its controlling the evap temp.
Generally my rule of thumb on American cars is 28-32 low side and unless its super hot high side should be below 250 and be able to rev engine to cruise speed and not get oddball spikes or fluctuations or cycling.
Converted cars are supposed to be tagged in two places, I generally do door or engine compartment and glove box but inside a console or in trunk/hatch area.
You can use some discretion. Total replacement of system say with vintage air or adapting from another car, at least make a tag for next person to work on it, listing oil, refrigerant and capacities.
I have had great success with these basic guidelines and procedures.
Also dont forget on new systems, pull them down at least an hour, my general rule. This removes as much moisture as possible.
Also I dont care which idiot tells you too reuse a r12 drier with r134a, hit them , hard with a blunt object, do major damage as they are ignorant fools.
R134a will "eat" r12 desiccant and destroy your system. And create black death and acids.
Been dong AC and conversion PROPERLY for over 27 yrs and never had my methods frag a system, had some reman compressors frag ,but it happens.
Heck my 71 Monte had POA/STV system and I converted it and it blew 38 degrees with no blower fan! and only had one hose bad which I replaced with a NAPA built hose with compression fittings.
I have been working on electric actuator controls for H body cars, now jsut need to pull my dash apart so I can adapt them to the box and finalize the actual control mods.
Oh and I am an ASE Master Tech, so it comes from practice not piddling.

[Monza Harry]

So Monza Racer how do I know if my new Receiver/Dryer has the right desiccant I purchased it at "AutoZone" about two years ago. I haven't refurb'd the system yet (just found the last piece of hard to find stuff just after Christmas) In Canada R12 has been outlawed for about ten years so I never even thought about unknowingly getting a non-compliant/compatible part. Harry

[zeke]

http://www.redtek.com/win_12a_prod.html

[BillB1210]

MonzaRacer,

Sorry I don't know your first name. But this posting is one of the most helpful ones I have ever read on this site. Very informative and I believe has the real "cautions" regarding conversions. I have always been skeptical of conversions, tried to keep R12 in my older vehicles and it still works great with low discharge temperatures.

Had my Monza converted to R134a by a reputable shop with lots of experience. Used a Sanden compressor, new orface tube, new dryer. Still it was not very cold, even here in western New York State. Cool not cold. Took it back, it checked out OK as far as pressures and freon content. Still not cold enough to cool the car on an 82 degree day.

I took a chance myself, installed a new low pressure switch, adjusted it so that it hardly cycled at all - can't remember if it was clockwise or CCW on the adjuster. Now the car is a "meat locker". Ice cold and very comfortable to drive to cruise-ins.

Was I just lucky or is this a normal "fix"?

Thanks,

Bill