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Subject: PDC retrofit update. So far, so good. Author: DavidC (moderator) : member since December, 2003 : 11918 posts Posted on: 2007-01-17 11:38:44

Last night I worked on the rear bumper assembly in my (thankfully) heated garage (as it was 21F outside), drilling holes for the new PDC (park distance control) sensors and re-finishing the black rubber parts of the bumper.


I decided to go with an aftermarket kit designed for another car, but I think it's going to look 100% "factory" when I'm done. The sensors look very similar to those used on the new Ford Expeditions. They're nearly flush with the bumper, more like what BMW used on the 1996-2001 e38's than the bulkier style they used on the e32's.


After removing the rear bumper, the black rubber parts were wet-sanded with 2,000-grit sandpaper. Note the white scratches at the corner of the bumper (courtesy of my wife in the grocery parking lot... -- no problem, though -- it looks new again, now). If your bumper has deep gouges or cuts, fill them in with automotive plastic putty and sand the surface smooth. After painting, you'll never know there was a blemish.


It took about an hour to drill four 21mm holes. The two outside holes were place 10cm outside of the vertical lines at the lower edge of the bumper, and the inner two holes were placed at 43.5cm inward from there. Placement of the two outermost sensors is critical, as there's a heavy metal bracket near the outer edges that you want to avoid. To protect the surface from scratches, masking tape was applied to the areas before drilling.


Here you can see the alignment of one of the sensors in the bumper. It is centered, vertically, below the bevel in the bumper.


A closeup of the 21mm hole saw.


Drilling in progress. The cordless drill didn't have the capacity to do all four holes, so I ended up switching to a corded hammer drill.




Drilling four holes in the bumper wasn't easy. Getting through the black plastic/rubber was ok but, due to the length of the sensors I needed to go through the aluminum bumper frame, too.




After all the non-rubber surfaces were masked off, Duplicolor Bumper Coat was used to spray paint the surfaces. The resulting finish looks great -- no sign of the white scratches that were once there. I'm planning to paint the lower valence area with black Duplicolor Trim Coat, too, to make it new again as well. I'll probably end up doing the front bumper and the side strips, too.

I've found the Duplicolor Bumper Coat and Trim Coat to be quite durable. Four years after painting the bumpers and mirrors of my '86 735i, they still look new with no signs of wear.



The PDC sensors were also painted to match the bumper. They're made to be paintable.


Here's a shot of one of the sensors before painting. You can see how the shiny black finish wouldn't match the bumper.


The sensors have a tapered edge so that they'll fit perfectly in the e32 bumper, which has a taper of approximately the same angle, letting the sensor remain parallel to the ground.


Later today I'll install the sensors and snake the wiring into the trunk. I'm planning to route the wires through the existing hole used by the passenger rear side-marker light. Power will be supplied by the +12V reverse lights. The piezo-electric beeper is pretty loud, so I think I'll mount it in or around the 3rd brake light in the rear parcel shelf.

More to come…

David Cecil

'97 740iL, 155k miles
'92 750iL, 90k miles
'86 735i, 101k miles

Visit e38.org for everything technical about your BMW

• PDC retrofit update. So far, so good. (pic) (url) - DavidC 2007-01-17 11:38:44 (18659 views)
  • Re: PDC retrofit update. So far, so good. - croshare 2007-01-18 19:58:33 (875 views)
  • where did U find UR 2000 grit paper? Hardware store or Car Parts store (nt) - Logun 2007-01-17 14:59:26 (535 views)
    • Advance Auto Parts, but most auto parts stores will have it. (nt) - DavidC 2007-01-17 17:00:03 (573 views)
    • Car paint store will always have it (nt) - Paparon 2007-01-17 16:28:31 (533 views)
  • Coming along nicely. (NT) (nt) - daryl12 91 735iL 2007-01-17 12:10:57 (633 views)