Vacuum & Recharge AC without gauges

[ptofimpact]

Fixing leaks in 89 Ranger, new Orings. Can anyone direct me how to vacuum AC system, Which side High or Low, How long to vacuum, without a set of Manifold guages. I know its not the perfect approach, but dont care to buy guages.
Would appreciate a basic explanation
Thanks

 

[sblake01]

Vacuum on the low side but you won't be able to tell when you've reached the goal (27 Hg) w/o gauges. I guess you could run the vacuum pump for 30 minutes (same as when I use my gauges) but you wouldn't really know if it's holding w/o gauges until you charge it. Then comes the prioblem of guessing how much refrigerant to use. I'm an HVAC/MVAC tech and I always gauges. Without them, it's really kind of hit and miss but I've seen it done.

 

[kimcrwbr1]

The longer you vac the better and you can find the factory charge on the label under the hood by weight and estimate how much refrigerant to add. Just not sure how you would keep the system into deep vac and add the refrigerant without sucking air/moisture. A single drop of moisture will destroy the compressor it creates acid in the system.

 

[sblake01]

Just not sure how you would keep the system into deep vac and add the refrigerant without sucking air/moisture.

I missed that one. When you remove the vac pump to put in the cans (I'm assuming you're using cans), you'll lose your vacuum, or at least, most of your vacuum.

 

[ptofimpact]

Thanks

sblake01, kimcrwbr1, thanks for your time time and expertise. I had this 'fixed' by a mechanic several seasons ago, replaced orings, vacuumed recharged, laster one season. Not many shops in my neck of the woods who will touch the old ac systems. I have been using Freeze 12 kits, sealer oil refrig,which lasts one season.
Wasnt looking to buy gauges, esp since I never used them, maybe check ebay, but then will have more questions.
Thanks for your help.

 

[sblake01]

In the long run, you'd be better off finding the leak. I did on my 90 Ranger when I bought it in 2009. It turned out to be a hose. I replaced the hose, charged it with the same Freeze 12 you're using which, by the way, is nothing more than a blend of R134a and HCFC 142b and some lubricant, and it still works to this day.

 

[Surrey]

Isn't there something very illegal about dumping refrigerant into the atmosphere?
It sounds like you need to fix your leak or something before adding more.

 

[fastpakr]

I'm not sure on R-134, but it's definitely illegal to vent R-12 (what the OP has in his '89) to the atmosphere which is what the OP will be indirectly doing by charging a system that is known to leak.

 

[fastpakr]

Also, found this for vacuuming your A-C system:
Air Vacuum Pump with R134A and R12 Connectors
$14.99 on sale at Harbor Freight. Looks like the reviews are pretty good (always check before buying HF products), and my local HF keeps it in stock.

 

[sblake01]

Also, found this for vacuuming your A-C system:
Air Vacuum Pump with R134A and R12 Connectors
$14.99 on sale at Harbor Freight. Looks like the reviews are pretty good (always check before buying HF products), and my local HF keeps it in stock.

Keep in mind that one is not self-containted. It requires an air compressor.

 

[sblake01]

I'm not sure on R-134, but it's definitely illegal to vent R-12 (what the OP has in his '89) to the atmosphere which is what the OP will be indirectly doing by charging a system that is known to leak.

It is illegal to vent any type of refrigerant, inlcuding R12, R134a, or any of the alternatives. It's also illegal to charge or top off a system that is known to leak.

 

[fastpakr]

Good point on the need for a compressor with the unit I linked. That would be a huge letdown if you didn't have one.

 

[ptofimpact]

Thanks to all....For the record, the system is Empty, refrig leaked out last season, and I am in the process of fixing the leaks, have a complete Oring set. wouldnt want the wonderful EPA at my door.
The leak is in what I will call the accumuator, long cylinder passenger side, near firewall, leaking at Orings.
I have that Harborfreight vacuum pump ordered, and have a Compressor in garage. Found a set of gauges on ebay new priced very reasonably[approx 40 bucks] if anyone interested in seller, I can get you an item number or link. Their not Pro stuff, pbly chinese, but for my use s/b ok.
I do appreciate all your help and expertise, and suspect I shall have more questions, Thanks~

 

[Earl43P]

Here's a good AC link from our Tech Library: http://www.therangerstation.com/Magazine/June04/tech.htm

I think your plan is sound. I would like to add that I service (quite a few cars every season) by outlet duct temperature. I use a quality dial thermometer and try to get <40 degree outlet duct temp air with the engine running about 2000 rpms, control on cold, not recirculate and a medium fan speed.

The sanity check is to do it that way, then drive it a steady 45 mph. The duct outlet temp should be LOWER than when you serviced it sitting still. If it is higher, you may have added a touch too much.

 

[ptofimpact]

Earl43P, Thank you for the info and suggestions. Not a tech here, just old school tinkerer who is more comfortable with the older stuff.
I checked out the link, which is excellent, but raised a question. The picture of the Evaporator, at the connector, which is attached to the hose returning to the compressor, is where the Orings are leaking in my Ranger. I noticed a type of 'clamp' holding the connector together...this is missing on mine..is that required?
Many thanks again.