How to recharge A/C on 92

[expert01]

I bought a R-134a A/C recharge kit because my 1992 Ford Explorer is just blowing hot air. I can't seem to locate the damn... low-pressure port, or the A/C compressor (I'm a real car noob). I don't have a chilton or Haynes either. Where is the low pressure port (in laymans terms-i.e. "Look in the back left corner for a valve on a hose that is 5/8 inches wide")? (BTW I just got this car from my brother, who treated it like crap, and I'm not sure when it was last recharged).

[XLT03]

Passenger side, black colored cylinder, half way behind battery. Low port is pointing straight up. I'm assuming that you are converting to R134a. You will need to take down the vaccum on the A/C system before you can recharge. You also need the convertor adapters for ports, R12 to R134a. Let us know how this works out.

[expert01]

okay, I saw an adapter kit at Wal-Mart, I'll go back and grab that. I figured it was that port, but the instructions said it was on a tube.

"You will need to take down the vaccum on the A/C system before you can recharge." err... how would I do that? I'm not too much of a car guy, I'm mostly into computers and modding.

[XLT03]

It requires a vaccum pump. You may find one at a toel rental place. If you don't have one you'll need to get a air conditioning manifold set to make the connections, it also has a valve to shut the system off so that you can connect the R134a. Go to Harbor freight tool company website to find the manifold set. You may want to check with out local garage to price out their services before you go further, it may be a wash in terms of cost and time. Please post your findings.

[expert01]

Alright, I've got R12 to R134a adapters (BTW, where is the high pressure port located at?). The instructions on the recharge kit say to start the car, turn on Max A/C at full blast, push on the coupler (to check the A/C system pressure), then proceed to fill to the correct levels. At which point do I take down the vacuum?

P.s.: I bought a 19oz bottle that came with a hose with an in-line pressure gauge, and an R12 to R134a adapter kit. It all set me back about $30 so far. And last I checked, it was a couple hundred to get it recharged by the idiot mechanics around here.

[XLT03]

Attach the manifold gauge set. You need to evacuate the system. Then take the vaccum down with vac. pump. Once vaccum is down to 29.99mm hg keep it there for 30 mins. Shut the manifold valve off. Turn vac pump off. Attach R134a to hose and follow instructions in filling the system with R134a. High side is on driver side near the compressor. You should only fill on the low side. On the 91-92 the charge is 1.75lbs. 19oz is a bit over 1lb. (ie 16oz = 1lb) so you'll need one more can. From what I can tell, your biggest roadblock is the vac. pump - you'll have to rent one. The hose w/ the R134a is not enough, this is where the manifold gauge set comes in.

Here is a typical setup:

Attach manifold gauge set (has 3 hoses) to low port, high port and the tap (for the R134a can without the hose setup) center hose. The center hose is attached to vac pump to take down vac. Open the valve on manifold and turn on pump for 30 mins. Close manifold valves. Turn off pump. Attach can tap onto center hose. Attach R134a can to tap. Pierce can with the tap. Open the valve on the tap. Start engine and then turn on A/C and open LOW port for charging. When 1st can is empty, close the LOW port valve on manifold. Remove 1st can from tap, install 2nd can onto tap. Again pierce can with the tap. Open LOW port manifold valve to add 2nd can R134a. At some point during addng R134a the compressor should start to cycle.

WARNING: USE A PAIR OF SAFETY GLASSES - YOU DON'T WANT TO FREEZE YOUR EYEBALLS!!!

[expert01]

Thank you for the clear instructions. I'm going to check around and see if anyone I know has a manifold gauge set (don't want to spend $100 on it), but I can't rent any equipment until the 4th is over.

[expert01]

You mentioned I would only have to get the manifold system if I couldn't find a vaccuum pump. If I could find just the pump, would I just empty the A/C system, connect the pump to the low port, leave it on until it's at 29.99hg, then disconnect the pump and fill the system (with the AC on)?

[steve11]

expert, you donthav a clue what you are doing and this is not a home-update job. not to pick on you, but you need a $300 pump and $100 hose set. you suck out all the old freon and air and pull a pure vacuum, then you leak the new freon into the system without getting any air or contamination back inside. then you fill it properly to get the right pressure. this is not a job for beginner without tools. i would suggest you get some local help.

[XLT03]

You need both manifold gauge set and vac. pump. As Expert11 mentioned this is not a typical home-update job unless you have a better understanding of what the job entails. Some jobs are better left for shops. Also by doing this job yourself does not mean that there isn't a leak somewhere in the system that requires more effort and parts replacement.