A/C Shraeder Valve replacement - Oh HumTech :-)

[jsbihn]

Hey all (and HumTech )
I have an issue with my A/C.
About two years ago or so I had my a/c compressor replaced by a local guy who does work for some of my Vette buddies. I would have done it myself but I was working 65-75 hours a week.

Well everything was bought new from NAPA and was working when I got the truck back.
Given there seemed to be cycling warm spot in the blowing a/c. Not too bad, but enough to be noticed, so I told the mechanic guy about it and he told me that he believed the shraeder valve had a little leak in it. He messed around with it and it seemed ok..... but then the car sat for a 4-6 months and the a/c wasnt cold or even cool anymore. A quick couple of bottles of R-134 recharge and all was well. Now it is a year later and the summer is coming and the air is failing again. I dont want to recharge it only to have it leak.... so I am looking to replace the valves.
Not sure if that is where the leak is at, but hey if the valves are bad and I put die in it.... it wont hold so I figure lets start here.

Anyways, I am wondering if there is a backyard mechanic way of doing this job.
Basically what I am thinking is the following, and tell me if it is or isnt possible and if it is or isnt the best way to do this. (please also tell me why if it isnt)

I figure that since the a/c is blowing warm air, with the occasional cool air coming through, that the freon in the system is basically gone. Especially since I can hear the a/c compression buzz every time it engages (lack of oil?).
So I figured that there is no real reason to try to recover anything.
Because of that, I figured I would use my shraeder valve removal tool and pull out the old valves.
Remember I am not putting any vacuum or pressure or anything on them, just opening the hood and pulling the valves out.

Ok next step would be to wipe away any schmutz inside the pipe where the valve was and put the new valves in.

Then I figured I would turn the vehicle on, turn the a/c on super cold and full blast, and put the recharge can on the low side. After about 2-3 cans, I figure it should be full and should be fine.

A/C a-ok.

Anyone see if this could be wrong/right/ or whatever?
Trying to do this on the cheap and as quick as possible. (especially since the last few days have been 85 with 85% humidity.... ahhh summer in the south)

Thanks