[bigtsr]

There is no need to be afraid of disconnecting the battery
cables from their respective terminals.
Try the negative first to get the feel of the action,
the only things that change from a long disconnect
are the radio settings.
Make sure the car is OFF and key is out of ignition.

 

[bigtsr]

The only thing I might caution on is to be
careful you don't short the battery posts
together via your metal wrench,that is definitely a no no.
Undo the negative first then while you are working
on the postive side cover the negative terminal
with a DRY work towel then once you get the positive
off cover that post also.