Unlike the coupe equivalents, the 451 cabrios do not have a specially designed emergency boot relase, should there be a problem with the boot release motor. The method in this guide may seem brutal but it is the only way of releasing the boot catches if you incur this problem.
Before you start, ensure that you have ruled out all other options (car battery, key fob battery, etc.)
To release the boot, we will be drilling two small holes in the boot liner from the inside and operating the catches manually. Start by clearing everything from your boot including the luggage cover.
We need to drill into the boot at the point indicated by the arrow on both side of the boot. As you can seem it is right on the edge of the boot liner.
Use a 4-5mm wood drill bit to cut through the plastic liner. It needs to be large enough to fit a long flat-blade screwdriver through to the mechanism behind.
Drill carefully. Try not to let the drill go too far into the boot panel once you have drilled through the liner. It is only about 3mm thick.
Repeat for the other side of the boot.
To release the catches, you will need to push a flatblade screwdriver into the holes but direct it towards the outer edges of the boot. You don't need to do both at the same time as the weight of the boot will keep the first one open while you work on the second.
You aim is to lever the boot release catch which is normally operated by a motor. This may take a few attempts! The following pictures demonstrate the solution once the boot had been opened. This should hopefully explain what you need to do! We recommend that you have someone else holding the boot as you release the second catch so that the boot doesn't suddenly fall open.
Boot in locked position (this is how the screwdriver needs to be inserted into the hole):
Boot lock in released position (click on the picture to reveal a video of the operation):