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How To Replace An Inner Fender Apron

A Good Body Shop Can Readily Replace A Vintage Mustang's Rusted-Out Inner Fender Apron In A Few Hours
March, 2009
By Miles Cook
Photography by Miles Cook
Npd Inner Fender Apron
NPD offers two passenger-side... 
   
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Npd Inner Fender Apron
NPD offers two passenger-side aprons for '67-'68 Mustangs. The one on the left with a black coating is known as an "import" version, while the "Canadian-made repro" on the right is bare metal. Though the one on the left is a few bucks more, Julian's determined that it seemed to be a better-made piece for several reasons.
Npd Inner Fender Apron Reverse
Not only is the coating already... 
   
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Npd Inner Fender Apron Reverse
Not only is the coating already in place on the apron at left, which prevents rust, note also its better-made mounting point for the battery tray. The bare metal version's battery-tray mount is more of a tacked-on afterthought rather than integrated.
Npd Coated Apron
Better quality on the coated... 
   
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Npd Coated Apron
Better quality on the coated apron at right is also evident here. The bending and curving of the metal is more factory-appearing, pronounced, and deliberate. The bare one's metal bends are less pronounced, and it's clear that it's not as well made as the coated panel. Also note the bottom hole on the coated panel is a square factory-correct cut, whereas the bare panel's rounded hole is simply a quicker and less involved cut. It was easier to go with the coated apron.
Ford Mustang Remove Battery Tray
The first order of business... 
   
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Ford Mustang Remove Battery Tray
The first order of business was to remove the car's battery tray, which was completely rusted out due to 40 years of battery-acid exposure.
Ford Mustang Original Apron
With the battery tray removed,... 
   
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Ford Mustang Original Apron
With the battery tray removed, you can see that the apron is toast. Panel replacement is absolutely the only correct way to repair this area of the car.
Ford Mustang Cutoff Old Apron
Removal of the old apron begins... 
   
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Ford Mustang Cutoff Old Apron
Removal of the old apron begins by cutting it out with a cutoff wheel, starting in front of the shock tower.
Ford Mustang Cutting Old Apron
Cutting continues down the... 
   
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Ford Mustang Cutting Old Apron
Cutting continues down the side of the apron. Note that the part of the apron that attaches to the shock tower isn't being cut. This is so the tower doesn't get touched. The strip section of the apron that remains attached to the tower will be removed later.
Ford Mustang Cutting Fender Apron
Cutting continues down the... 
   
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Ford Mustang Cutting Fender Apron
Cutting continues down the side of the tower and along the front subframe. Again, it's clear the body techs at Julian's are doing this right because both the tower and front subframe won't be altered at all during removal of the old apron and installation of the new one.
Ford Mustang Separate Apron From Core Support
Further effort to avoid damaging... 
   
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Ford Mustang Separate Apron From Core Support
Further effort to avoid damaging other panels on the car--in this case the radiator core support--is evident by use of an air-powered saw to gently separate the apron from the core support.
Ford Mustang Cut Stock Apron
After a little more cutting... 
   
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Ford Mustang Cut Stock Apron
After a little more cutting where the apron and core support join at the bottom, the old apron is nearly cut free from the car.
Ford Mustang Remove Panel
With the panel cut out, it's... 
   
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Ford Mustang Remove Panel
With the panel cut out, it's then lifted out of the car.
Ford Mustang Remove Apron Remainder
With the main apron panel... 
   
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Ford Mustang Remove Apron Remainder
With the main apron panel removed, work then commences on removing the remainder of the apron still attached to other panels, including the shock tower (shown here), the radiator core support, and the front subframe. Here, the spot welds that joined the apron at the top of the shock tower are ground away.
Ford Mustang Peel Away Shock Tower Apron
Once the spot welds are ground... 
   
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Ford Mustang Peel Away Shock Tower Apron
Once the spot welds are ground off, the strip of apron still attached to the shock tower can be peeled away.
Ford Mustang Grind Spot Welds
More careful grinding down... 
   
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Ford Mustang Grind Spot Welds
More careful grinding down of the spot welds continues on the strip of apron that attached to the front subframe.
Ford Mustang Cut Away Apron Strip
You can see the strip here... 
   
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Ford Mustang Cut Away Apron Strip
You can see the strip here that was actually part of the old apron. With the main part of apron already removed, it's been partially and carefully cut away from the shock tower, which avoids damaging the tower.
Ford Mustang Remove Old Apron Strip
Further work continues on... 
   
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Ford Mustang Remove Old Apron Strip
Further work continues on removal of the remaining strip of old apron. The shop tech is now using an air-powered chisel to gently separate it from the front subframe.
Ford Mustang Clean With Sandpaper Wheel
With all of the old apron... 
   
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Ford Mustang Clean With Sandpaper Wheel
With all of the old apron finally removed, the surfaces to be welded together need to be cleaned up with a sandpaper wheel. Everything on the car where the apron attaches is thoroughly cleaned, including the shock tower, radiator core support, and front subframe.
Ford Mustang Reshaping Parts
Though the various pieces... 
   
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Ford Mustang Reshaping Parts
Though the various pieces that attach to the new apron were in good shape, some minor shaping and straightening was required, which was easily done with a shaping hammer.
Ford Mustang Drill Holes In New Apron
Preparation of the new apron... 
   
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Ford Mustang Drill Holes In New Apron
Preparation of the new apron begins with a series of small holes drilled in the edge for the spot welds to attach it to the car.
Ford Mustang Test Fit Apron
With all the holes in place... 
   
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Ford Mustang Test Fit Apron
With all the holes in place and each one scuffed clean of the black coating, the apron is then test-fitted to the car.
Ford Mustang Spot Weld Drilled Holes
Before spot-welding, the apron... 
   
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Ford Mustang Spot Weld Drilled Holes
Before spot-welding, the apron is temporarily screwed into place in about four locations, which will locate it for the spot welds.
Ford Mustang Smooth Spot Weld
Once the spot welds are completed,... 
   
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Ford Mustang Smooth Spot Weld
Once the spot welds are completed, they're smoothed down with a sandpaper wheel until the line of welds becomes invisible and the strip where the apron joins with the shock tower matches the rest of the apron surface.
Ford Mustang Screw In Apron
Every hole that's been drilled... 
   
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Ford Mustang Screw In Apron
Every hole that's been drilled into the apron gets spot-welded. The welds start at the top of the shock tower, then run down the side and across the subframe.
Ford Mustang New Coil Spring Cover Holes
To complete the installation,... 
   
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Ford Mustang New Coil Spring Cover Holes
To complete the installation, new holes are drilled to match those in the coil-spring cover. The existing holes in the cover are used as a template.
Ford Mustang Installed Inner Fender Apron
Here's the installed apron... 
   
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Ford Mustang Installed Inner Fender Apron
Here's the installed apron from inside the engine compartment. It's ready for surface preparation, painting, and a new battery tray. A shop like Julian's can do this sort of metal removal-and-replacement work quite easily. This project was complete in less than three hours.
Julian's Collision Center
6926 Lankershim Blvd
North Hollywood
CA  91605
National Parts Depot
800/521-6104

www.npdlink.com

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