What you must do is remove the atmosphere from the innards of the icebox freon highway. Any air inside that equation will cause the freon to react and make ice. My little home made vacuum pump is a multi-tasker. It not only blows but it sucks also. That makes it ideal to remove air from the system. You need to connect a red hose from your gauges to the vacuum pumper. When you have allowed enough time to get that low side gauge down to negative 30 AND you feel enough time have elapsed to get all the moisture out the sealed system then with the vacuum pump a going you close off the red valve on the high side hose. You shut down the vacuum pump. You wait. Why? You want to see if the pressure drops on the system. If it drops you still have a leak. If after a long while all night OR at least an hour the needle ain't moved then you can be fairly sure the repair is holding and their are no more leaks. At that point you would open the freon a hair and SLOWLY add the gas to prevent damaging the valves inside the compressor. You would then crank the unit up. and slowly add in the freon NEVER allowing the needle to get above 10PSI.
This is a time consuming process. If you rush this step you fug it up. Kapish?
Once the pressure remains steady at 5PSI you stop and allow the ice box to get cold inside. If you have 5 PSI close off the tap and wait 24 hours for the result.
Notice I didn't have to remove any hoses after vacuuming out the system? This is critical. You could vacuum to the moon and back but if you had to remove the hoses to connect your rig to the ice box to charge it, you would allow air to get into the sealed system and fug it up. That is why you need gauges.