(almost) invisible parking sensors - howto

[berre]

Hi all,

 

I've been looking for an aesthetic solution for parking sensors for a while now...

 

I started with an invisible-behind-the-bumper solution (cheap thing from china) which worked amazingly well... except in the rain

As we have a lot of rain here in Belgium (just like in the UK I guess) this wasn't an option.

 

I then went for the Cobra f394 & r394 (flush mount parking sensors)... but with a twist.... The result is pretty good imho so I hope this small tutorial can help someone who is looking for a clean parking solution.

 

Note this is just for the rear bumper for now, if I have time I will do a howto on the front bumper as well once I get around to fitting the sensors

 

Step one: buy Cobra f394 (front) & r394 (rear) kits

> or only r394 if you just want rear parking sensors

They are not the cheapest but they are flush mount and quality seems to be great compared to some other after market kits I've seen

 

Step two: cut the rubber protection back as far as possible using a cutter knife:

(do not pull the rubber protection out)

 

It should look something like this:

As you can see there is still rubber protection present to protect the inside of the sensor

 

Step three: paint the sensors (in my case magic-black)

I bought the spray-can kit from the skoda dealer (contains the paint and the varnish)

I did not sand the sensors, only degreased them and primed with Motip plastic primer.

This primer is very good, I used it in the past even on mirror-like surfaces and the paint doesn't come off

 

 

To mask the sensors for paint, here's a small trick: push some painters tape really hard on the edge of the sensors, this will show an outline on the tape which you can cut out.

 

Step four (the scary part): drill holes

Here I have spent the most time on, I tested different tools e.g. punch tool, hole saw, ...

 

... but I ended up getting the best (perfect) result with a step drill.

Using a step drill however can be a bit dangerous, if you don't focus you can easily go one step too far and end up with a hole which is too big.

The trick here is to put electrical tape so that the last visible diameter is the one you want (red arrow) and drill very carefully towards the end.

 

But don't be afraid to drill, the electrical tape really helps to avoid "overshooting" but just take your time and be careful... if possible you could try to get a piece of bumper from a scrap yard to do some test drilling and build up your confidence.

 

 

Most important piece of information of this whole how-to is the diameter: 14mm!

This is an exact fit for the sensors (without the rubber rings off course)

 

Now for the location of the holes first thing to get is the centre of the bumper.

You can use a vertical lazer if you have one available (align on the centre of the lock on your boot) or simply go by the markings on the bumper.

 

For this you need to remove the plastic bumper strip (which you will need to do anyway), this is done by using a flat screw driver but be careful not to mess up your paint. I use a piece of cloth as a lever:

 

 

In the center of the bumper you will see a round dot like shown on the picture, that's centre.

 

Now put some painters tape on your bumper so that you can make the markings for the holes.

 

In my case I have put the centre of the sensors about 45mm below the bottom of the bumper strip.

I used 40 cm for distance between the sensors, so measure 20cm either side of the centre - those are your 2 middle sensors - and measure another 40cm on both sides.

 

If you want you can always connect everything and do a test setup by taping your sensors to the desired locations.

Do note that getting the sensors disconnected again is fiddly work (tiny connectors)!

 

 

Now once you have everything marked you can start the drilling.

I first used a small steel drill big enough to fit the first step of your stepdrill because this will help centre the stepdrill.

So if the smallest step on your stepdrill is 4mm, then you first pre-drill with a 4mm steel drill

 

And then you drill:

 

 

As you can see it's not a perfect hole at the back, it looks like the plastic has been pushed back, don't worry about that, we'll fix that once the bumper is off.

And so we come to the next point:

 

Step five: remove bumper

For this it's best you have a second person helping you but it possible doing it on your own if you take some precautions like putting a thick blanket on the floor in case the bumper drops to the floor

 

Remove the plastic strip between the lights, this clicks right off.

Behind it are 4 torx screws you need to remove:

 

 

Then you need to remove the pieces of plastic below the lights, for that you need to remove a small screw and then slide the plastic towards the center of the boot:

 

 

Then remove all torx screws in the wheel arch and below the bumper.

There are 4 screws in either wheel arch, and 5 screws at the bottom of the bumper

It can be difficult to fit a screwdriver in the wheel arch, especially if you are running 18" wheels so I used a torx bit and a lock plier:

 

 

Finally remove or pull back the inner interior fabric in the boot, this should expose two bolts on either side

Use a 10mm wrench to remove these:

 

Now when you undo these your bumper may or may not fall off , in my case it didn't, I needed to wiggle just a bit and it came of.

If you are working alone - as mentioned - take precautions like putting a thick blanket or an old rug on the floor.

I also put some tape on the bodywork just above the bumper:

 

 

 

Step six: complete holes

Once the bumper is off we first need to fix the holes (remember the plastic was pushed towards the rear of the bumper?)

This is how it looks:

 

 

To get rid of this just drill from the back of the bumper using the same step drill, again be very careful and make sure the hole is 14mm throughout.

(test this by inserting a sensor, it should go all the way through)

 

Step seven: mount the sensors

I'm not going into much detail here, the instructions are very clear... just make sure that the front of the sensors are perfectly aligned with the outside of the bumper.

Make sure to de-grease the inside of the bumper and use strong tape to fix the wires:

 

 

The instructions do mention you need to drill a hole through the bodywork to guide the cables in the boot but I just guided them via the vents:

 

 

 

Step eight: put your bumper back on

Same as step five but the other way around

 

Step nine: connect module, buzzer

easiest part of the whole thing, just stick the module and the buzzer somewhere in your trunk (I placed them behind the interior fabric against the side) and  connect the wires... the wires of the modules are easy... for the power you need to strip the ground wire and the wire of the reversing light.

In my case the ground wire is a brown wire (should be connected to the black wire of the module) and the reversing light wire is a blue/black one (should be connected to the red wire of the module)

 

 

 

Step ten: enjoy parking sensors you hardly see

My brother visited me today, looked at my car and asked when the hell I was going to install my parking sensors

(in his defence they have been lying around the house for a couple of months now)

 

And the results...

 

detail pic taken about 10cm from the sensor:

 

Full view (sorry for the lousy pic, it's indoor and car is dirty - I'll take a better one after a wash):

 

 

And there you go... hope this helps someone...

 

Cheers

B

 

 

 

 

[Ray Luxury-Yacht]

That's an absolutely beautiful job there my friend, bloody well done - lovely to see the time and trouble you took.

 

Nice work!

[SuperbTWM]

A hex bit attachment for a 1/4" ratchet is a lot easier to use than a pair of mole grips you know 

 

Excecellet job, very tidy

[berre]

A hex bit attachment for a 1/4" ratchet is a lot easier to use than a pair of mole grips you know 

 

Excecellet job, very tidy

 

didn't have that at my disposal I'm afraid... wasn't really an issue as it was just to undo the screws a bit, once they were loose I could just remove them by hand

 

thx

B