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Repair or Recharge? Another A/C Thread


The_Epsicle

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I drive a 1994 Ford Ranger 4.0 with R-134A from the factory. The A/C hasn't worked since I bought this truck in November last year and I figure I might try to repair it myself. Some of you may remember my recent attempt to recharge the system: A/C high pressure gauge line exploded

Anyway I feel like I haven't had enough frostbite yet so I want to try again, I followed a terrible instruction video last time that told me to jump 12 volts directly to the compressor, I now realize that was almost a suicide attempt and I should never, ever do that again. I can't help but feel my failed recharge was only caused by my own stupidity.

1. My manifold gauge exploded because the system couldn't shut off the compressor to avoid the explosion. I should clarify that the line was not harmed, but has always had some surface rust on the inline filter.

2. I did not properly evacuate and pull a vacuum on the system beforehand, the system held a charge before but I did not realize it was mildly charged until I disconnected the compressor to take my valve covers off. This is why the system was completely depressurized at the start of my last recharge attempt.

3. I was not paying attention but walked away from the gauges to check to see if I was getting cold air in the cab(I was), if I had been paying attention I probably could have avoided the explosion.

Because of those three points I am considering taking my truck to an A/C shop to have them properly evacuate and pull a vacuum on the system then I will recharge it. I know I need to replace the o-rings on the compressor(because they're missing) but other than that I don't believe I have any leaks. As far as I see a proper recharge is at least worth a shot, but then again I thought it was a good idea to jump 12 volts to the compressor so I figured I'd see if I'm being stupid again before I do this.
 
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4x4junkie

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I guess whether you should repair it or not hinges on how much you really want A/C... Out here in the desert southwest A/C is almost mandatory (especially when the early-summer monsoonal moisture comes in, as it's been doing the last couple weeks), so I've always made sure the A/C works in all my rides.

If you think you've learned enough since your last incident, then I certainly won't discourage you from giving it another shot...
A good resource I used when I did the A/C on my BII was this Haynes manual on air conditioning. It explains in pretty good detail all the ins & outs of servicing an A/C system (unlike their vehicular manuals, which those seem to be a lot more general).
There is also www.autoacforum.com which I found very informative also.


Since yours is the same as one of mine ('94 4.0L w/factory R-134a), I should mention that on mine there was a pressure relief valve on the low (suction) side that always leaked during high underhood temperatures while the A/C was off (typically while driving off road at high elevation). I removed it since I hadn't ever seen one there on anything else before and it seems to serve no purpose other than to let all your freon out into the atmosphere anyway (the high side is where the high-pressure danger is, which I have to wonder if your hose was weak to begin with, your high-side relief valve should've opened before your hose burst).

Anyway, hope that helps.
 

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My only input on this is that without good scales it is very hard to recharge an AC system properly. It can't be done correctly by pressure and temp alone, they just aren't accurate enough.

Since it sounds like you already vented your system once I would open it up at the compressor SLOWLY, and then replace the seals you want to replace, then probably replace the rest of them too, and when you take it to the shop to have them pull a vacuum just let them charge it while they already have the machine hooked up. The vacuum will take 20 to 40 minutes, charging it will take less than 2.
 

The_Epsicle

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Thanks for the replies. A/C is a must here in the summer, the humidity kills you and since I've got a black truck I lose 10 lbs from sweating when I drive across town. I've got it scheduled to be vacuumed out and recharged at a local shop and I've replaced the o-rings on the compressor. Normally I don't do this for fear of damaging the system, but considering my other option was to replace just about everything but the compressor I'm not really concerned about damaging the system so I'm going to have the guy put some leak stopper in there too.
 

4x4junkie

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I'm not really concerned about damaging the system so I'm going to have the guy put some leak stopper in there too.
If your local shop guy is any good, he will refuse to put leak stopper in there.

Do a quick search for "leak sealer" on autoacforum, I'm sure you'll quickly see the many reasons why this is bad. You've already had the system opened, just replace the rest of the O-rings (none of them are particularly hard to get to). Much easier than revisiting this issue again in the near future because the leak stopper clogged up other parts of your system.

You should replace the accumulator too if you haven't already.
 

The_Epsicle

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Don't worry he refused to put leak stopper in there, even if the system is trashed.
 

The_Epsicle

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I've got cold air! He said I passed the leak test and he didn't see anything wrong with the system, no blockages were showing up on the pressure gauges. He found some residue on the low pressure check port but that is all he found anywhere, he doesn't think the leak amounts to much but said I should keep an eye on it.
 

4x4junkie

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Glad to hear it all worked out.

It's always nice to have cold air on a hot day. :cool:
 


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