How to Keep Dirt, Gravel, Snow from Filling Up Inside Rear Bumper

[Fleetw00d]

If you don't like the way your rear bumper catches dirt, gravel, snow, etc. thrown up by the rear tires, even with mud flaps, block the space off. I made a panel out of ABS plastic (heat formable) that fits inside the rear bumper that goes forward to the top of the back of the mud flap. Passenger side shown below. It is notched to fit around the lower bumper mount. I had to do some more trimming and a little forming to clear the tow hook (removed in the photos below). I used screws (same screw used to attach bumper cover to the side brackets) to attach the panel to the underside of the bumper. Still need to make one for the left side.

[Granite CB7]

That is awesome, nice work! Something I should've done along time ago when I dd'd my CB, I should do this to my Odyssey instead! Where did you buy the ABS plastic that you used? Seems like this sort of mod could be adapted for aerodynamics to avoid the rear bumper being a parachute too

[wildBill83]

Looks nice, isn't it kinda close to your exhaust? +rep for a cool idea to extend the life of our CB7s.

[Fleetw00d]

This is the first one I did, I may have to trim it back from the exhaust some. I was going to start with the left side because it is simpler (no exhaust and simpler tow hook to avoid), but made the first bend in the wrong direction. I should keep better track and maybe make a paper pattern I could duplicate to save others some trouble if interested. This is on a 90-91.

[wildBill83]

Cool, one last question ... maybe ... is gravity the only thing holding it in?

[drew12000]

Good idea. Where you get the plastic? And once installed. How far are the edges to the bottom of the trunk?

[civic_90_08]

With that being ABS plastic, and it being right at your exhaust, are you worried about it warping? I've been thinking about making one of these, but all one piece and out of thin aluminum or some thin sheet metal.

[Fleetw00d]

Cool, one last question ... maybe ... is gravity the only thing holding it in?

At the moment, there are four screws (look close). Three along the side (one hidden by the mud flap) and one in back that go through a hole drilled in the cover (slightly larger than the screw shank), then threaded into the ABS. It just rests on top of the back of the mud flap for now. This one is pretty hard up against the tow hook.

Good idea. Where you get the plastic? And once installed. How far are the edges to the bottom of the trunk?

Got the ABS from a local Grainger store. 2 x 4 sheet, enough for two cars. What is the material the bumper covers are made of (it might be easier to work with)? It took a fair amount of heating with a gun to get it to a temperature where I could form it, so I'm not too concerned about it warping. If it does so considerably, I'll cut it back, or make one out of another material. It doesn't go up to the trunk floor, it is mostly a flat piece that is mounted on top of the bottom lip of the bumper cover, the piece I bent up on the side I thought about drilling a hole through the tow hook and attaching there, but on this side I wound up having to cut it off to clear the hook. The bend on the right in the first photo fits inside the back of the mud flap. The angled bend (upper right), I did to discourage stuff from going on top of it. The rear end (left in the photo), I had to offset down about the thickness of the material to better fit the recess across the back edge of the bumper.

[Fleetw00d]

My brother sent me some CAD software and a quick model of this panel. I'll have to tweek it some dimensionally, then maybe find some place that can 3D print it.

[cb9love]

My brother sent me some CAD software and a quick model of this panel. I'll have to tweek it some dimensionally, then maybe find some place that can 3D print it.

if the cost is reasonable for production then this is a a great idea.

[EsperHamid]

everytime I look at CB7, I say to myself, this car has room for more.