Can I rebuild AC system in steps?
 

I need to swap my AC compressor, condenser and drier after my compressor seized last year and snapped the drive belt. Unfortunately my Runner is my only running vehicle right now and my time to work on it is very limited due to full time work schedule. I was wondering if I could change out the condenser and drier in the evening one night this week and do the compressor on the weekend then get it it vac tested for leaks and filled? Or do I need to do all the work in one shot?

Nope, you can replace components in it in steps up till it gets vacuumed down. Then it will be time to add refrigerant.

Best to get all the parts and crack the lines once.

I would suggest you get all the parts and do everything at once. It is not too terribly complicated. Once the system is open, the drier accumulates moisture (which you do not want. If you put on a new drier and then open the system again, it probably won't work as well....just my two cents....

If you're going to do it in steps, put the drier in LAST. There's a reason for the name, you want it to "work" within your closed system, not be used up in atmospheric air.

YMMV, but I have done two AC repairs lately where the systems stayed depressurized over the winter. One was sort of open to the atmosphere; it was a BMW 3 that hit a 'coon and the condenser line cracked. The other was an evaporator leak that was down to zero pressure by Christmas after a last charge in August.

When I finally got around to fixing them, I left them a good long time on the vacuum pump, and they came back to life good as new. New driers, obviously.

I think you got all the answer already.

I just did the entire thing this weekend. If your reasonably skilled and have everything on hand you can do the tear down and re-install in about 4-6 hours.

I pulled everything out and then started with the evap core and worked my way forward. The last thing I did was the drier.

I borrowed a vac setup from a friend and then pulled a vacuum right away, so the drier was only open for maybe 2-3 mins. after 30 mins on vac I closed the manifolds and let it sit overnight... checked it first thing and re-pulled with the pump just to make sure it had zero leaks.

getting it re-charged tomorrow morning on a machine.

I could have charged it but... I just want to know it's setup correctly. robots can do a better job than me.

as long as you pulled a vac each time you replaced a part of it, honestly I can't see why you can't do it piece by piece but... I think I would want to pull a vac on it after each part and then for sure drier last.