72 A/C Compressor Clutch Replacement

[brown7373]

IUs it possible to replace the compressor clutch without discharging the A/C system? Mine fried yesterday, but I am pretty sure the rest of the system is fine.

Here is the sequence of events. Last week, I smelled electrical component burn smell. I reached under the control unit and the blower switch was very hot and some melted goo burned my finger. I replaced the switch with a used one I had. The A/C worked fine, but I had to giggle the switch to get it to make contact and work on 2nd speed only. So I bought a new switch, but not installed yet. So yesterday, with used bad switch, I smelled the burning electric smell again, then I could feel the engine straining to turn the compressor and the system lost cooling. I shut it off and the clutch was so hot, all the paint was off it and it was sizzling hot.

First, is there a procedure to replace clutch without discharge or do0 I need a whole compressor and clutch?

Could a bad switch cause a clutch failure, since the compressor shuts off when the blower switch is off? Might I have a bad blower motor causing switches to fail?

Factory A/C with 134a and POA calibrated for 134a.