Toyota Repair: Toyota A/C problem, r 134 freon, valve cores

Question
Thanks for the quick response. As a follow-up I was wondering if it makes sense for me to try an install the change-over R134 A/C kit or do you think that it requires tools that only a repair shop or dealer would have. My thinking is that if the compressor requires changing I will have a lot of the system apart already.....Also, do auto-part stores such as Autozone sell these kits or do you buy through a Toyota dealer...........thanks
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Followup To

Question -
I have a 1992 Toyota Celica with A/C problems. It has the old system and began to show signs that it needed to be charged (expensive I know). However, before I had a chance to take it to be charged the fuse blew when I turned the A/C on shutting down the gauges. I replaced the fuse and all was OK until I hit the A/C botton and again blew the fuse.
Would low freon cause the fuse to blow or do you think it may be a short in the compressor clutch..etc. Last question, approx how much shown it cost to convert over to the new  system................Thank you.


Answer -
The fuse is going out because of excessive current draw which could be caused by a seizing clutch or compressor, look at the compressor clutch, if it's the problem it will be burned, if it's not then try to rotate the small pulley on the clutch, if it can't be turned the compressor is seized, in case that the clutch is burned up the compressor may have caused it and it may be best to replace both. If the compressor is replaced make sure to replace the receiver drier unit also. If the toyota dealer does the conversion to R-134 freon it will probably cost around $150 using an aftermarket kit but first the fuse blowing problem needs to be addressed and the system restored to a workeable condition.

Answer
Buy the entire kit from Autozone or any other autoparts place, it should come with the fittings and the R-134 freon and fill kit, you will need two cans of freon, make sure the old valve cores are removed, a tire valve core removal tool is needed, there may be a bunch of o-rings included in the kit use thes on any lines that have been opened, check for any metal particles from the old compressor in the lines, finally be sure to replace the receiver drier also, when filling the freon put in one can and then start the engine turn the a/c on, watch the sight glass on the receiver for bubbles, attach the other can of freon and add more but shut off the valve on the can as soon as all bubbles in the glass have disappeared, do not overcharge the system, it will take about one and one half cans.