One of the read parking sensors on my car has slipped back inside the bumper a bit, it still works but looks a bit crap. I have tried to push it back out flush by putting my hand behind the tow eye cover and then using a bent coat  hanger to push the sensor back out. This has proved fruitless.

 

 

Has anyone had the same problem? Any ideas as to how i can do it easily or is it a bumper off job?

To do it properly its bumper off.

If its the side by the exhaust you can reach up behind there (when the pipes are cold) with small hands.

If its the other side then try removing the small undertray. You might get that off and have some access. I haven't tried that though.

To do it properly its bumper off.

If its the side by the exhaust you can reach up behind there (when the pipes are cold) with small hands.

If its the other side then try removing the small undertray. You might get that off and have some access. I haven't tried that though.

 

the under tray doesn't make it much easier because the crash bar behind the bumper gets in the way, When i remove the tow eye plastic cover i can get my arm in but I need my arm to be about 6 inches longer or something that can get me enough purchase on the back of the sensor to push it out.

 

The cars under warranty but I suspect it is caused by the fitting of the tow bar so probably won't be covered.

Taking the bumper off isn't too complex and requires only basic tools with little to break along the way.

It's just time consuming.

At least that way you'll be able to fix it back in properly with decent glue.

I'm in the process of replacing the two inner sensors.

Removing the four screws holding the lower bumper and bending back the plastic and wedging it temporarily gives just enough access to work singlehandedly.

You'll be able to lay behind the car with one arm on the inside and the other on the outside.

You may need to pull off the whole sensor/holder to apply some contact adhesive if the holder is loose.

I'm in the process of replacing the two inner sensors.

Removing the four screws holding the lower bumper and bending back the plastic and wedging it temporarily gives just enough access to work singlehandedly.

You'll be able to lay behind the car with one arm on the inside and the other on the outside.

You may need to pull off the whole sensor/holder to apply some contact adhesive if the holder is loose.

 

 

This sounds a possibility , i will give it a go at the weekend when i am intending to fit my winter wheels.

 

I dont suppose anyone has an image of these screws?

You can't miss them on the underside of the rear bumper, torx but I can't say offhand what size... small.

Screws on mine are T25... Arnie is back for the nth time!

Still hoping I can resurrect duff sensors once I get them out, hopefully tomorrow.

After all they are just ultrasonic transceivers, a little bit of reverse engineering required (no pun intended) to see what literally makes them tick.

Unfortunately the sensors (if they are OEM) are not just ultrasonic transceivers. The sensor module contains some electronics that pre-processes the signal before sending digital data back to the control unit in the boot. I guess that this explains why they are so expensive.

 

The circuit is sealed in potting compound so I fear that they are not that easy to repair. I just bought some pre-painted ones from this seller:

 

http://www.ebay.co.uk/itm/PDC-REVERSING-PARKING-SENSOR-AUDI-VW-SKODA-7H0919275C-NEW-ORGINAL-/321253117100?pt=UK_CarsParts_Vehicles_CarParts_SM&hash=item4acc2d8cac

Yes I found out that they are indeed sealed units so no repair could be attempted, disassembly results in broken internals.

Which makes you wonder why some people blame water ingress for faulty sensors, surely if they are kept clean and are not faulting there is absolutely no reason why they should play up in the rain.

Keep them clean and maybe even a wipe with a water repellant product to prevent heavy rain build up on the surface eg car wax, rain x, wd-40, Teflon.

EDIT to previous post...

Perhaps a water repellant isn't such a good idea as beads of water will surely hamper ultrasound more than a thin film.

Much as windows with beading water are harder to see through than untreated glass with a uniform film of water.