When I aquired my '95 Blazer about 3.5 years ago the last owner had the A/C system recharged at a quick lube place. The A/C worked fine until the next spring when I noticed the air at the vents wasn't as cold. I put some dye in the system...searched and found that the high side service port was leaking. Since I rarely drove the Blazer at the time I made a cork gasket and placed it in the service port cap and tightened it to slow down the leak. Now that I am finding that I like driving the Blazer now more than my Ford Ranger and since the temperature outside is 85° in March, I am assuming we are going to have a hell of a hot summer. Sooooo...question is, if I have a friend of mine evacuate the freon and leave a little positive pressure in the system, is it possible to replace service port and recharge without pulling a Vacuum. Also, before I am asked, the friend removing the freon is not a A/C tech, he works at a junkyard and they have to evacuate all cars as they are brought into the yard.

 

Replacement valve cores, (Schrader valves) are available, but it must be rated for A/C, one for a tire will not work. If the schrader doesn't stop the leak, the high pressure line from the condenser to the fixed orifice tube fitting will need replacement. As for draining the system... These HVAC systems are extremely sensitive to the amount of refrigerant and oil used in them. An ounce or two over or under will greatly affect its performance. Without evacuating the system to 29.4" Hg (1 atmosphere) for at least an hour, it is impossible to remove water vapor & accurately charge the system.

 

thanks for the reply Captain Hook. Valve in mind is the kind with the rubber ball in it.

Guess i'll hit the pawn shops for a Vacuum Pump before the summer rush. Since I'm going to pull the vacuum guess I'll replace the accumulator too. Thanks.

 

Good idea. Might have your boneyard buddy see if he can get you the aluminum line with the fitting in it, probably save you a bunch of fooling around.

 

for a simple vacuum pump try a finding a busted refrigerator. pull the compressor out and solder a threaded fitting to the lines from it. That is what I use and it works just fine. I put a gauge and a shutoff valve on it so i can plug in the compressor build up vacuum then shut the valve adn unplug the compressor and it holds vacuum. well as long as teh AC system is sealed...

 

Dont do that. It's better than nothing but wont pull anywhere near 29. I tried one that was working good when removed and it barely got to 20". They arent made for that.
look on Harbor freight for that 99 dollar pump.. mind you it needs oil to work to 29 and for self lube. Then look for one of the same on CL or pawns
BTW, I bought a surplus wobl compressor years ago and used it on countless fixes and installs.
It pulls 25" and I've never had a failure either on cars or residential. I run it for a couple hours.
The KEY is to always replace the accum anytime the system is open or low {pressure under ambient temp scale} for any length of time.

If your junkyard friend can pull to 26" for an hour or two that will do it, with new accum. The warmer the day, the better it works to remove water molecules.
mind you for evac of old units, if there's a known system leak, the EPA reg is to stop when pressure is at 0". I assume he does it that way.

 

thanks for the reply pettyfog, the friend at the junkyard can't leave it on the machine that long. He is just going to recover the freon for me so I can properly change the leaking valve and replace the accumulator. Just wondering if you know anyone that has purchased that vacuum pump from Harbor Freight. I have had issues with items from them, for example an angle grinder that went into full meltdown while using it. Will it survive a full hour running at full vacuum? Thanks again your input is greatly appreciated.

 

ok, first, PettyFog, I admit that you know a LOT about these trucks that I dont. when I read a comment that you posted advising someone how to do something I automatically think that you know what your talking about...

But I hate to say that you are wrong but... Well i will just post a vid that I just made.

Vid...

I simply am doing this as I have been using different refrigerator compressors for a number of years on many different vehicles and have never had a problem with them not pulling enough vacuum. this is a much cheaper option for some people who cannot find an AC vacuum pump for sale and would have to order one online or what not. I pulled this current compressor out of a small fridge that was about 3 feet high... you know, the size you find in an office or a dorm.

 

I don't doubt it works..you have video proof. But your method would involve me finding a good compressor from a working fridge and a torch to solder the fittings and the hardware needed for it. you probably had these things lying around and I don't. It would probably cost me more to build one than actually buy one. I would also say that it would involve me releasing freon in the atmosphere, but that would make me sound like an enviromentalist.. which I obviously am not..... I drive a Gas Sipping Blazer!!!! anyways I do like your vacuum pump, in some form I guess you can call it recycling..lol

 

actually I only had the torch... but yea I understand what your saying, I just dont like being told that something dosent work by some one that doesnt know that when i know it does, and in PM's from a couple other people here others know it to. im all about options for people. Not saying one is better than another, just simple options.