https://www.hagerty.com/articles-videos/art...nts-and-the-lawFrom the Haggerty's site.
I've done this one.
Evac everything and flush it completely. Change the orifice tube for R13. Get a new drier to make sure there is NO moisture or dirt in the system. I went through a can of flush agent and blew it through everything with really dry air.
Get or rent a gauge set if you don't have one already. Hook up the set and pull vacuum enough to boil of ANY residual moisture and to check for leaks.
Charge the systems and check your gauge set for the recommend temp split to amount of refrigerant at the correct pressure.
Should be good to go after that, but check it on a good hot day. You didn't state how the evap coil or condensing coil is set up but that could also be an issue as well.
If you didn't completely flush the system you will stunt the lifespan of your compressor.
Good luck.
Edit.....I feel old sometimes....I should have said orifice tube not expansion valve. If you clean and flush your system well the exp valve sb ok.