has anyone changed the spring in a bv while still on the car?

does the groved ring have to come off to remove the old spring or just the ****?
is it under pressure?thanks in advance steve, have one very weak hand so it's hard to hold something in place to long, this has to be a one handed job

 

if your running an agency power bv turning the **** will change the tension on the spring (tighter for higher horse cars backed out for stockers) I have one and I run it about one and a half turns. I am bone stock in performance. If this is what you have turning the **** all the way would just have the **** come out. To replace the spring you would have to uninstall it from the car and undo all the bolts around the top. Be aware even with the **** turned all the way out there is still some tension on the plunger. Try to push it in and you will see what I mean.
But why are you thinking about changing the spring? Are you running crazy boost? If its popping off to easily just give it a little turn.
Of course this applies to agency power's bv, but I imagine other models are probably similar.