I changed my heater core the other week and now need to regas..

the A/C worked before but was gradually getting less effective so im wondering what i should replace..

im assuiming the Compressor is still good...but the system may have gotten some dirt in it because ive had the lines disconnected for a couple of weeks because i was goijng to use new seals...

so what else should i replace? ive heard u need to change receiver dryer and maybe tx vavle...

dont want to spend $120 only to have it leak away soon after..

you can change the receiver dryer..
while it has no gas i would also change the o rings on both sides of the tx valve and any that would be on the condensor aswell as the ones on the compressor.
i dont know about the tx valve??
ive never had one fail.but ya never know..
as i used a second hand one when i converted my ea over..

Change all o`ring seals, if it has only been empty for a little while everything else should be ok. They should put a dye in the system to check for leaks before filling it up with r134a.