A/c compreser is it hard to change on a 90 lexus

Hi, you may want to get a Chilton's manual to make removal much easier.That particular year, you would have to look in the manual to see if it uses the older R-12 Freon, or the new R-134A. I assume that the system is out of freon, and you are sure the compressor is bad, using the manual to help in removal will save you headaches.Now, after replacing this, the system will have to be evacuated with a vacuum pump to remove non-condensables , as air and moisture which enters a sealed system as soon as you open it up. The compressor canno't compress air or moisture and will cause failure after a very short time, and improper operation. So, all you really have to deal with is installing new compressor, have it evacuated or rent one and do this if you have the experience, and the best way to charge an auto a/c as they may hold a pound and 1/2, it will show you the oz. it takes to charge it. Lets say it takes 22oz of R-134A. get a 16 oz can and a 12 oz can.Once you get the larger of the to cans in, the clutch will start to engage as you are above the low pressure switch, so it will pull the rest in fast, 6oz give or take an oz. If it is the old expensive R-12 that you have to be certified to buy, they now do have a direct replacement for R-12, I can't quite remember the name, but it is ozone safe and you are able to buy it over the counter at about $10.00 per 12 oz. Yes, if you worked as an auto a/c me-ch, and to do this by law you would have to recover the freon and not release it into the open, as the E.P.A. can fine you $25,000 the 1st time!! Good Luck on this project and feel free to contact me if you need some help. Sincerely,
Shastalaker7

yes and you need special tools and equipment to properly vaccuum out the sytem before recharging it.