BOA279

iTrader: (1)

I just ordered everything I need to open my own AC shop ^^ ...seriously though I've done quite a bit of reading and I don't think AC is that difficult at all if you have the right tools but in all my reading there are a few questions that I couldn't find answers to. If your an AC guru please chime in.

1. The system must be empty before you vacuum it correct? It seems obvious but nowhere is it really specified. I assume it would be vented to atmosphere through the vacuum pump.

2. question one brings me to two...how do you get the compressor oil out? How do you know how much is in there and how much to add?

3. Finally, my gauges show zero pressure on either side (low/high) so there is obviously a leak. What, minus the compressor, would you recommend I replace as preventative. Is there a sponsor that sells everything? Id really like to get new compressor lines, dryer/accu., orifice and new seals.

Any help appreciated

00silver6

iTrader: (4)

if your gauges are showing you zero psig then its empty. put a vacuum pump on it and bring it down to 29mg turn the pump off and let it sit for a while and see if it holds if it doesnt you have a leak some where.

if there is a leak it could be minor like valve stem those are a weak point usually.

i would put the pump on it first and see if it holds

im kind of going off of residential and other stuff i realy havent had to work on a vehicle hvac system yet

fleetmgr

Yes, or you'll damage your vacuum pump. Venting to atmosphere is actually illegal, although that's what most people do at home as the cost of a recovery unit is pretty steep.

The only way to know for sure that you have all of the old oil out is to flush the system. However, the system holds so little oil to begin with, you won't hurt it by having more than is recommended. I believe there are 2 specs for oil fill, one with a flush and one without. You'll have to do some checking, or just put in the recommended amount and not worry about it. The way automotive systems are designed, the chances of having it all back in the compressor are nil anyway.

Replacing the lines would be a huge waste of money unless you know one of them is leaking somewhere other than at a joint. A couple of the lines may be dealer only. If you want insurance on the job, then I'd replace every oring in the system. Put in a new dryer and an orifice tube. Take a good look at the conderser, and make sure it isn't plugged with a bunch of bugs, rocks etc. Also, make sure the fins are straight. If need be, get a fin comb and straighten them back out.

When I put a vacuum on the system, I like to hold it for at least 4 hours. This ensures that any moisture in the oil has a chance to boil out. If you've done all the seal replacements correctly, you should be able to pull a 29.7" vacuum, shut the valves on the manifold and not lose any vacuum over that time period. That deep a vacuum is what it takes to ensure that the moisture will indeed boil, it drops the boiling point of water to about 35 degrees F.

BOA279

iTrader: (1)

@fleetmgr

Your the man...I shouldn't have to worry about doing anything illegal as my car has vented it to atmosphere for me ^^. Ive had the car for 3-4 years and the AC has never worked so I dont know what condition anything is in. Im debating throwing a can of 134 in there just to see it the compressor turns on. As far as the condenser, I have a transmission cooler in front of it....how big of a deal will that make? Thanks for the responses. ^^

fleetmgr

Well, if you're gonna throw some refrigerant in there anyway, get the kind with dye in it so you can see what's leaking. At this point, you're probably looking at a new compressor no matter what you do, but you might get lucky and not have a bad compressor seal. Don't count on it though. Were it me, I'd pull the tranny cooler and have a look see just to be sure.

samson_420

iTrader: (1)

Also if the system sat this long, I would flush it through a bit. . . Not the compressor, but the lines, the condenser and evaporator.

99'CajunFirehawk157

iTrader: (57)

Just curious, in these fbody cars, is their a common faulty part with these A/c systems, Mine leaks a Lil over a few year period as it sits primarily, I notice my compressor seems oily and I see you mentioned compressor seal...???

BOA279

iTrader: (1)

Is this seal replaceable? I bought a leak detector but if I understand its only for refrigerants so filling the system with nitrogen or anything else will not allow the detector to work. I will pull the tranny cooler and take a look at the fins. If the compressor doesn't turn on, I may just rip out the whole system and replace/clean everything. Might as well do it right...

fleetmgr

The seal isn't commonly replaced on it's own, but if you can get the part then go for it. If you want to do a pressure test w/o refrigerant, get some nitrogen (dry, oil free), and change your leak detection method to a soap bubble test on all the joints. It's a very good leak detection method for gross leaks. Most detectors though will find a leak that's as small as 1 ounce/year, and a soap test won't find that. Just don't put more pressure in the system than refrigerant would with the system operating on a hot day. Take a look at a P/T chart for pressure info.

If the compressor won't start on it's own, get ten cents worth of wire and jump it straight to the battery. You'll know soon enough if it's seized or not.

fleetmgr

Trust me, it's not unique to F bodies. An A/C system on any car is merely a leak waiting to happen. The single biggest favor you can do your A/C is to run it every couple of weeks over the winter. This would keep most systems happy for years longer than they currently last.

BOA279

iTrader: (1)

do you have any idea if they make a "seal" kit with all the o-rings needed for all the lines?

fleetmgr

Not to my knowledge, unfortunately.