Can you install an A/C bypass pulley without discharging the refrigerant?

By pass pulley takes the place of the ac compressor. The compressor has to be removed to install the by pass.

As Dandy said. I doubt there is room to safely secure the compressor in the engine bay once you pull the a/c and install the by-pass. BTW the R-134a will vapourize once the pressure is reduced to atmosphere. Use gloves and remove the fill cap put a small rock in the cap and thread the cap back on until the gas starts escaping. Once the gas has bled out the a/c compressor can be removed. This chemical is used in some brands of electronic air duster cans so you releasing it to atm is no different than blowing out a few computers. IMO

Wouldn't it be simpler to go to NAPA and get a shorter serpentine belt; by passing the mounted ac comp. entirely?

In some cases just using a shorter belt will work but i have tried that several times and most of the times I would have to modify idler or tensioner pullies in some shape or form to get the belt to clear(miss hitting) itself when routed without ac in the loop. I have found that installing an ac by pass is much easier.

I've successfully fit shorter belts on a number of vehicles. Some even allowed the compressor to remain in place, but... You NEED to trace your new routing vs. the original, and make sure that the water pump won't be run in reverse! Can't see that working out real well.

Intentionally venting your refrigerant to the atmosphere is illegal. Take it to a shop and ask them to evacuate the system.

Once your system is evacuated, you can safely remove the compressor and bolt in the bypass and use the belt. Also remember to tell stores when you get a replacement belt that you HAVE a/c or you will get the wrong belt. If you cap your refrigerant lines, it will save the condensers and lines for future reinstallation should you decide to fix.

How much does it cost to clean your AC system and should the vehicle still make noise once you replace the AC compressor with a bypass pulley