I am in the process of re-charging R12, but now I am stuck and need some help.

Here is a summary of what I have done so far:

Replaced compressor (reman), drier, pressure switch and temp switch, and all o-rings under the hood.

I flushed the high side which came out clean. i then decided to leave the low side alone. I did not replace the exp valve. this could have been my costly mistake.

I put about 7.5 oz mineral oil in the compressor, and about 0.3 oz in the drier, then assembled them back in.

I pulled vacuum overnight, closed the manifold valves thereafter for about an hour and observed vacuum held with no problems.

I then started charging with the first can. After about 2 minutes with the first can charging and engine off, I observed the low pressure went up to 90 psi and high side at 40 psi. I noticed there was some more left in the can so I dipped the can in hot water and it continued to charge. at this point I am thinking the low side is showing pressure too high. I decided to proceed with the second can, turned the engine on and heard the compressor engaging, but no cold air. I did not hear or see the 2nd can discharging at all. I thought it is because the pressure inside the system is now too high compared with the pressure inside the can.

any insights would be appreciated.