I assume this was a bumper off to fit these sensors ? How easy ? I have a faulty one to replace but do not want to get stuck with the bumper on the driveway when Monday morning comes
I assume you have the original equipment ones. If they are aftermarket they will just pull ot of the bumper. The details below are for OE sensors
If it's one of the outermost you could probably do it without removing the bumper: lying down feel the rear of the parking sensor inside the bumper, you should feel a spring and the wiring connector off at rightangles. Now, holding the 'fish eye' against the bumper on the outside, push the sensor from the inside towards the outside of the bumper and then turn it clockwise (as if you were looking at the sensor from behind the bumper). The sensor should slide out of the 'fish eye' and you can disconnect the wiring connector and replace it.
Well, first clean the bumper so that it doesn't get scratched.
Then take a rear wheel off and undo the five screws holding the wheelarch liner to the rear bumper. Then pull back the liner and undo the bolt that holds the front edge of the bumper to the bodywork. If you can support this side of the vehicle whilst you do the other side fine, if not refit the rear wheel (I just used a couple of wheel bolts because it has to come off again when refitting. Then do the same to the other side.
After that there's the visible bolts at the top (4) and bottom (3) of the bumper.
Then remove the tie down hooks nearest the rear of the car and pull back the carpet on each side. There are three bolts under the rear lights that need to be removed from each side.
You don't have to remove the plastic panel that goes under the tailgate, but it might help when moving the carpet.
Make sure you've got something soft for the bumper to rest on, it likes to sit face down so to speak. The bumper will now slide off - not far because the wiring is still connected in the offside rear corner. I couldn't get mine undone, but there was enough slack anyway.
Now you can see the parking sensors are just bayonet fittings on the 'fish eye'.
Once separated take the spring and plastic ring off the old sensor and fit to the new sensor.
At this point I slid the bumper onto the car and checked that the sensors worked.
Please note that it is important to align the bumper correctly as you refit. There is a small raised circle on the leading edge of the bumper that corresponds to a hole in the bodywork. I used the bolts next to these finger tight to locate the bumper first. Other than that, refitting is the reverse of removal!
Undertake this at your own risk! It took me about a morning.
Fitting aftermarket sensors from the outside is way easier!