Someone school me on 73 Duster rear bumper.

Hello all,

I have read the posts pertaining to changing out bumpers on 74 and later Dusters and have questions.

Is a 73 rear bumper the same as 70-72 with the exception of the extra reinforcement?

Why when a 70-72 bumper is put on a 73-74 Is there usually a gap between bumper and 1/4? Since the 1/4 panels didn't change in that location it would seem to me if the proper bumper brackets are used, an earlier bumper should sit flush all the way across.

What am I missing?

The ‘73 Duster rear bumpers are basically the same as the ‘70-72, they’re non-shock mount. They should mount up the same way, with the same gap. A 70-72 bumper should bolt straight on.

72bluNblu said:

The ‘73 Duster rear bumpers are basically the same as the ‘70-72, they’re non-shock mount. They should mount up the same way, with the same gap. A 70-72 bumper should bolt straight on.

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Thanks 72bluNblu,

So a 70-72 bumper should fit flush, on a 74 without gaps using 70-72 brackets?

cpearce said:

Thanks 72bluNblu,

So a 70-72 bumper should fit flush, on a 74 without gaps using 70-72 brackets?

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On a ‘73, yes. On a ‘74, nope. ‘74’s had shock mounted rear bumpers. Whole different ball game from a ‘73.

72bluNblu said:

On a ‘73, yes. On a ‘74, nope. ‘74’s had shock mounted rear bumpers. Whole different ball game from a ‘73.

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I understand about having to remove or collapse the shock absorbers on a 74 and or fill the rear panel or fabricate brackets. My biggest concern was the gaps at the end. I want to end up with a clean flush mount.
My initial post may have been misleading and for that I apologize. The car is a 74 and I want the clean look of a 73.

Yeah that’s a different story.

The ‘74 quarters are different, there’s no flange in the bumper cut out area. So, you can pull the bumper in by mounting an earlier bumper on standard brackets. But there will still be a gap that the 70-73 cars don’t have.

I did this conversion on my ‘74. The first time through I just made some brackets to replace the shock mounts, collapsing those is more trouble than it’s worth. That allowed me to use the stock 70-73 brackets. Here’s the post with that info

My "new" '74 Duster- or why I need a project like a hole in the head

The second time around I cleaned it up to make it look more factory for 70-73. I filled the holes for the old shock mounts and added a flange to the end of the frame rail like the early cars to the to get rid of my homemade brackets. I also made a filler piece to mimic the looks of the early quarters, so at least at first glance it looks right. Here’s that post and pictures. Title shows up the same, different post I swear.

My "new" '74 Duster- or why I need a project like a hole in the head

72bluNblu said:

Yeah that’s a different story.

The ‘74 quarters are different, there’s no flange in the bumper cut out area. So, you can pull the bumper in by mounting an earlier bumper on standard brackets. But there will still be a gap that the 70-73 cars don’t have.

I did this conversion on my ‘74. The first time through I just made some brackets to replace the shock mounts, collapsing those is more trouble than it’s worth. That allowed me to use the stock 70-73 brackets. Here’s the post with that info

My "new" '74 Duster- or why I need a project like a hole in the head

The second time around I cleaned it up to make it look more factory for 70-73. I filled the holes for the old shock mounts and added a flange to the end of the frame rail like the early cars to the to get rid of my homemade brackets. I also made a filler piece to mimic the looks of the early quarters, so at least at first glance it looks right. Here’s that post and pictures. Title shows up the same, different post I swear.

My "new" '74 Duster- or why I need a project like a hole in the head

Click to expand...

Thanks again,
I was mistakenly under the impression the 1/4's were the exact same, there is the source of my confusion. I had bee told the 1/4 panels were the same, although I didn't have 2 cars to compare. Even the aftermarket AMD panels are listed as same for 73-76. There must be slight variances in bumper area. This explains why earlier bumpers on 74's have the gaps. I am familiar with Darts, this is my first Duster.

The only real difference is the cut out for the bumper. On the 70-73 cars there’s a flange where the quarter is joined the thr tail panel, the quarter has the bumper relief stamped in and then the flange sticks out and covers the gap between the bumper and the tail panel. On the 74-76 cars the quarter just ends there, it has a 90* corner that just overlays thr tail panel.

You can tuck the early bumper in on the 74-76 cars just fine, but you can see around the end of the bumper because there’s no flange. The 74-76 cars just had that plastic filler piece because the bumper stuck out farther to account for the shock mount bumper brackets.

I’ll see if I can post better pictures of the difference in the quarter.

72bluNblu said:

The only real difference is the cut out for the bumper. On the 70-73 cars there’s a flange where the quarter is joined the thr tail panel, the quarter has the bumper relief stamped in and then the flange sticks out and covers the gap between the bumper and the tail panel. On the 74-76 cars the quarter just ends there, it has a 90* corner that just overlays thr tail panel.

You can tuck the early bumper in on the 74-76 cars just fine, but you can see around the end of the bumper because there’s no flange. The 74-76 cars just had that plastic filler piece because the bumper stuck out farther to account for the shock mount bumper brackets.

I’ll see if I can post better pictures of the difference in the quarter.

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I wonder if the filler panel could be trimmed down to fill the gap?

cpearce said:

I wonder if the filler panel could be trimmed down to fill the gap?

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Not really. I tried with one of the filler end pieces I had. The way they’re shaped and the plastic material they’re made of just doesn’t work well. I mean, you can do it, but it’s not as easy as it sounds and it’s not going to look very good. Or at least I couldn’t get mine to look good enough for it to be worthwhile. It doesn’t look bad without the filler, it just doesn’t look exactly like a 70-73 car. But you have to look right at that gap to know it’s a conversion, I drove my car for quite awhile with the earlier bumper and that recess just open before I added the metal flanges to mimic the earlier cars. The only place it’s different is in the bumper recess on the corners.

Here's some better pictures showing the differences in the rear panel and the quarter.

Here's a stock '74, should look a lot like yours. One thing to notice is that the rear bumper is actually wider than the tail of the car, by quite a bit. So the plastic filler actually angles out quite a bit.



Here's a stock '73, although the '70-72 cars should look pretty much the same except for the tail and marker lights. You can see the large flange that sticks out from quarter at the recess for the bumper.


So, if you mount a '70-73 bumper on a '74+ car, you get a gap like this one


Notice though that in the picture above the bumper is pretty much the same width as the tail of the car, the bumper doesn't stick out past the quarter panels like the '74 bumper does, so the plastic filler is the wrong shape. All you need is a flat piece like the early cars had. I looked at a bunch of pictures of the original cars, then made a template and some filler pieces. I made the filler piece out of two parts and welded them together, just like the factory 70-73 cars so it has the same look. Then I welded it to the flat end of the quarter panel and filled it



And the "finished product" with the bumper in place looks like this, pretty similar to the 70-73 cars. Obviously I'll have a little more bodywork to do here when I paint the car.


Also, I filled in the holes in the rear panel for the shock mounts. I just made a couple of patches and welded them in. Then, I made a copy of the reinforcing flange on the frame rail. The other side of the rail has this flange for the bumper mount, so I made a copy and added it behind the patch.

Here's the other side of the frame rail, the arrow shows where the flange is and how the hole is actually still in the flange to locate the 70-73 style bumper brackets.

The other side of the rail, showing the back of the patch I welded in and the mounting hole for the 70-73 brackets

Here's the flange I made up

And the whole thing welded in place. Now the 70-73 standard bumper bracket just bolts in place like stock.

Thanks

72bluNblu said:

Here's some better pictures showing the differences in the rear panel and the quarter.

Here's a stock '74, should look a lot like yours. One thing to notice is that the rear bumper is actually wider than the tail of the car, by quite a bit. So the plastic filler actually angles out quite a bit.
View attachment 1715155270
View attachment 1715155264

Here's a stock '73, although the '70-72 cars should look pretty much the same except for the tail and marker lights. You can see the large flange that sticks out from quarter at the recess for the bumper.
View attachment 1715155266

So, if you mount a '70-73 bumper on a '74+ car, you get a gap like this one
View attachment 1715155265

Notice though that in the picture above the bumper is pretty much the same width as the tail of the car, the bumper doesn't stick out past the quarter panels like the '74 bumper does, so the plastic filler is the wrong shape. All you need is a flat piece like the early cars had. I looked at a bunch of pictures of the original cars, then made a template and some filler pieces. I made the filler piece out of two parts and welded them together, just like the factory 70-73 cars so it has the same look. Then I welded it to the flat end of the quarter panel and filled it
View attachment 1715155268
View attachment 1715155272

And the "finished product" with the bumper in place looks like this, pretty similar to the 70-73 cars. Obviously I'll have a little more bodywork to do here when I paint the car.
View attachment 1715155273

Also, I filled in the holes in the rear panel for the shock mounts. I just made a couple of patches and welded them in. Then, I made a copy of the reinforcing flange on the frame rail. The other side of the rail has this flange for the bumper mount, so I made a copy and added it behind the patch.

Here's the other side of the frame rail, the arrow shows where the flange is and how the hole is actually still in the flange to locate the 70-73 style bumper brackets.
View attachment 1715155276
The other side of the rail, showing the back of the patch I welded in and the mounting hole for the 70-73 brackets
View attachment 1715155267
Here's the flange I made up
View attachment 1715155263
And the whole thing welded in place. Now the 70-73 standard bumper bracket just bolts in place like stock.
View attachment 1715155269

Click to expand...

Totally awesome! Thanks so much.

Since my car is all painted I might try making those extensions, paint them, and try fastening with auto body adhesive.

cpearce said:

Since my car is all painted I might try making those extensions, paint them, and try fastening with auto body adhesive.

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I'd be more inclined to do something like this
100 Inch Foam Front Bumper Lip Kit Splitter Chin Spoiler Valance Fit Chrysler EZ | eBay

Panel bond requires prep too, it's not just magic glue. If your car is painted, I'd just use the 3m backed foam stuff. Or just leave it alone, like I said the only place you notice any difference at all is at the ends of the bumper to the quarter. You really have to be looking for it to notice it at all.

@72bluNblu
Maybe this piece could be helpful. It fits against the back of the quarter panel flange area being discussed. In the AMD picture, it is flipped but you can tell how it fits.