| I posted this back in 2004 but it was in general and the pics are dead. Reposting it with more permanent links. Check the pics if you're unsure what I mean. A LOT of Z owners have this problem. Some think they ran into something but the real cause is usually the heat from the license plate lights slowly heating the urethane to a point that it bows inward. I took the Z to a few body shops to see if they thought it could be fixed on the car. All told me it'd have to be removed and redone for roughly $200 or so. Rather than throw money away, I figured I could do it myself. I'm sure someone must have tried this before, but in all my posts over the last year about it in Tech/Gen I haven't seen anyone mention it. Here's the problem. If you look in the center of the bumper, you'll see where the reflection in the paint bows a little. In fact, it's quite obvious looking at the rear in almost any light, but it's perfectly centered on most cars...so most people live with it. 
Here are some more angles of it 
Now, I had a few different ways to tackle this, but in the end it was the easiest method that worked the best. My original plan was to cut the piece of urethane in this picture and put a spacer between it to push the bowed area out. 
I checked behind the plate and made sure cutting this area wouldn't cause any other areas to be weakened. Once I was sure, I used my trusty dremel to cut the piece. 
The problem I realized right after I cut it was that the area behind the license plate is hollow and absorbs the pressure of putting a spacer in between the area I cut. As such, it just pushes the plate back in rather than the bumper outward. I had thought of using some sort of expanding foam or some rubber to brace it when I realized an even easier way. I figured if I put a spacer between the black mounting bracket of the license plate lights and the actual bumper surface itself, it would push that part out. Unfortunately, even that wouldn't work because while the urethane flexes too much. What happens is no matter what size plastic/rubber you use, it still bows just a little bit because the urethane just beyond the rubber part bows inward. I thought this would work perfectly but it came close at best. Here's the piece I used. I later cut it in half with the dremel and jammed it between the metal light bracket and bumper. Before cutting and inserting
 Jammed into place. You can barely see it sticking out. Again, this did NOT work.
 While I was fishing this piece out from my test fitting, I stumbled on something even easier. Once I cut that tab separating the two pieces, I noticed that if I pulled down on the outermost tab (attached to the bumper side) it made the bow disappear. Insert lightbulbs going off over my head. I jammed the piece of plastic I had between the light bracket and the tab itself (instead of between the bumper and the bracket. This made the tab angle downward a bit, but you CANNOT see it at all unless you crawl under the car. Again, this is hard to explain, but use the picture below. The part labeled "WRONG" was where I had it originally. The part labeled "RIGHT" is where it now rests. The blue line is there to give you an idea of how the black light bracket lines up behind the tab. You want it ON the bracket, not between it and the bumper like the first attempt. Once you get under there, you'll realize you can use a multitude of items to get the desired result. You may even be able to do this without cutting the tab as I did. I'm sure there's 100 ways to do it, but using what I had in the garage worked great. 
The piece stays in there quite tight all by itself, but I decided to silicone it into place. There's no chance of it moving now and you can't even tell the tab is pushed downward without bending way down. After half an hour it ended up being the easiest of my three ideas and worked the best. Here are the results :) 
Notice how you can't see the tab sticking down, even this close and low to the ground. Perfect! Time to spend that $200 on something more worthwhile =)
"Find out just what any people will quietly submit to and you have the exact measure
of the injustice and wrong which will be imposed on them." - Frederick Douglas |
DIY: Fix for common "bowing" or dent on the Z's rear bumper - 
