Modern Vespa

How do I lube the parking brake cable so it fully releases?

The service manual doesn't say much about the cable itself but it does say allot about the parking brake subsystems.

https://www.manualslib.com/manual/1337951/Piaggio-Mp3-400-I-E.html?page=313#manual

The cable itself and its components are behind a fair bit of plastic. You'll need to prepare yourself with the right tools for prying plastic safely to fully access it.

Lubing a sticky cable only buys you a bit of time.

Given the amount of labor involved it is best just to replace the cable

I really don't have the heart to remove all the fairing to get at the parking brake assembly.
Has anyone had any success in removing the rear connection and injecting penetrating oil into the cable? Perhaps there is some way to pressure inject lubrication into the sleeve.
Currently I have to pull the lever down to disengage the brake each time, so it does move and is not totally seized.

It's not that hard to replace the parking brake cable. The one on my Fuoco seized up (first sign was not releasing easily...) and I replaced it. For a lot of the distance you can use the old one to pull the new one through. Just a few zip-ties and other clamps to undo first.

The cable wasn't completely seized so I kept working the parking lever back and forth and it slowly released the brake. All is good now. Being in winter storage in an unheated garage may have been the issue, even though the parking brake was off.

motion pro makes 2 style of cable lube tools and they also have excellent cable lube spray.

seen the age 2008 most likely its the caliper it self
the little axle twist a wormwheel that push the pads out its a non greasable part