Clean-look ParkAssist

[PaulDash]

My MY99 car came with the rare option 635 ParkAssist (called Einparkhilfe in German). It wasn't common probably because the parking sensors themselves are really ugly. On the Boxster 'dat @ss is so pretty. These are like four warts.

After almost three years of ownership and three years of having to look at them, and also prompted by damage to my rear bumper (Another story. Nürburgring. Wet.), I decided to do a custom mod to hide them.

Don't get me wrong, the ParkAssist is great functionality even in a sports car. Our streets in Europe are much more narrow than in the US and many parking spots are simply tiny. The plan is to retain the original system, make the mod somewhat reversible, yet have a nice clean look of more modern cars.


Looking even uglier on my dirty, damaged bumper.

[PaulDash]

Step one is to remove the rear bumper. There's 6 screws along the bottom edge, 2 in the wheel wells almost in the very corners of the bumper, and 3 underneath the air spoiler (I left these out when swapping bumpers during testing). You don't need to jack up the car. With all the screws out, grab one side and pull sideways from the wheel liner. The wiring is connected by one plug.

Porsche came up with a strange mounting system for the parking sensors. Here's how the sensor fits, and all the elements:


Part numbers (from left to right):
- housing 996.505.865.00
- sensor 996.606.171.00.9A4
- ring (Really, a rubber washer. More on this later.) 996.606.471.00
- retainer spring inner 996.505.667.00
- retainer spring outer 996.505.669.00
- washer 999.025.262.02
- cover inner left 986.505.859.00
- cover inner right 986.505.860.00
- cover outer left 986.505.861.00
- cover outer right 986.505.862.00

These are for cars until MY02, parts for MY03 and later are different. The inner/outer is position relative to center of bumper. Notice the only parts that are unique to a Boxster are the covers as the 996 bumper has a slightly curvier shape.

Also worth mentioning is that the outside left cover is (usually) painted white on the inside as this sensor is special. You see, this is a complex system that communicates between the sensors and one of them is the "primary".

The sensors themselves are Bosch sensors typical for those production years. Mine was marked as "0 263 003 010" although others might work with our control unit.

[steved0x]

Originally Posted by PaulDash

The wiring is connected by one plug.

The Bentley has us disconnecting the license plate bulb housings and pushing them up through the bumper, I think next time I am going to do it your way - I saw that plug once I had the bumper off and I was like man....

[PaulDash]

Let me skip to the effect I want to achieve. I will go back and talk about the process and tools, but right now I'm just testing things out.

The good news is that I've almost gotten the look I was after. Maybe the sensors are inset a little more than I'd like, but they do disappear into the shape of the bumper. This is before painting (of both the sensor surface and entire bumper):



Also, my "alternative" mounting method survived the heat. Literally. I participated in a 1-on-1 driver training event this Friday and pushed the car really hard all day.

The bad news is that I may have to get another bumper and drill holes again.

As mentioned in my second post, these sensors communicate between each other. One sends out an ultrasound signal and the others listen for the echo. They alternate in who is sending and who is "listening". Their interaction is most likely tuned to the particular setup like their relative position and angles. While drilling, I made a few small adjustments to the hole positions to have them sit more flush and now I'm sometimes getting some false beep tone and the interval of the intermittent tone is not exactly what it was before (with respect to distance to obstacle).

The next trial for the system is coming up this week - a trip to Cologne and back. If everything survives, I'll post more details about the process.

[BRAN]

subscribed...i just installed park distance sensors myself (4 front + 4 back) + 2 blind spot sensors.
up front it is impossible to install an inner mounting system, the bumper is just to close to the cover.

My blind spot sensors have an inner mounting system...and it was not easy to get both of them plain with the surface, depending in the angle and thickness of the cover. sanding inside might help a little.

[hab5000]

Just wondering if there's a follow up to this?

I've recently bought a 986S with the ugly parking sensors. Looking to mod them in a similar way to the OP's.

I'd love to know how he fitted them without the horrendous covers!


Alternatively, I'm thinking of fitting aftermarket ones, so if anyone knows the diameter of the holes for the original sensors in the bumper that would be great.

[Coaster]

Originally Posted by BRAN

subscribed...i just installed park distance sensors myself (4 front + 4 back) + 2 blind spot sensors.
up front it is impossible to install an inner mounting system, the bumper is just to close to the cover.

My blind spot sensors have an inner mounting system...and it was not easy to get both of them plain with the surface, depending in the angle and thickness of the cover. sanding inside might help a little.

Which System / kit did you install?

[PaulDash]

Originally Posted by hab5000

Just wondering if there's a follow up to this?

Thanks for asking. I've been working a lot and not spending much time here on the forum or at improving my ParkAssist mount. The temporary mounting method did survive my trip to Cologne and even two laps on the Nürburgring.

Here's what I did:

The first thing I got was new rubber washers to replace part 996.606.471.00 as I wanted to have black ones for a better effect. Porsche only has semi-transparent ones, but Mercedes has them in black (part number 0005420351).

I drilled a 24mm hole for the sensor and widened it to about 28mm in half of the thickness of the bumper cover plastic to get the sensor to sit (somewhat) flush. The provisional mount is not pretty and not (easily) removable - basically industry silicone glue:


What I want to do:

Ultimately, I'd like to create a mounting plate that would be glued to the inside of the bumper cover and where the existing housing would simply snap-in. Based on a 3D scan I did of the ParkAssist sensor cover, this isn't that hard.

[hab5000]

Thanks for that. Messy but effective!

[PaulDash]

Originally Posted by hab5000

Thanks for that. Messy but effective!

Messy indeed, but this was just a proof-of-concept.

From the outside it looks much better (even with my spray-painted bumper):


Before having my bumper (-s and other parts) painted, I'm considering prototyping a mount that would hold the sensor and glue to the bumper plastic. Would anyone else be interested in that?

[tsVestor]

Nice work, can you please tell me what diameters are the stock holes in the bumper or what diameter does the Bosch sensor have?

[fridsten]

This is interesting. I have the 635 option as well, and although I don't mind it very much, it disturbs the look of the rear end.

[PaulDash]

Still driving around with my spray-painted bumper. Kind of an outlaw look, if I might say so.

Originally Posted by tsVestor

Nice work, can you please tell me what diameters are the stock holes in the bumper or what diameter does the Bosch sensor have?

Anyway, sorry for the delay in answering.

(CORRECTED DIAMETERS 3.08.2017)
The Bosch sensor face is 20mm in diameter. I drilled the holes to be 25mm, plus some sanding, to accommodate the rubber washer. I didn't measure the diameter of the sensor body.

As I have a fragment of the old bumper for the very purpose of measuring the size (and placement) of the original holes, here's the sizes below. Note that these holes are irregular (might have been a dealer-installed option???) and that there's a little 2mm notch (orientation shouldn't matter) to prevent the rear mounting from twisting.