Tail Light Panel and Trunk Floor – Part 2

Well……as much as I whine about sand blasting, I can’t deny its unmatched usefulness in auto restoration.  So, while the weather continued to offer opportunity to do so, I put on my “big-boy pants” and set to it once again to properly clean the flange areas of rust scale and better evaluate the wheel opening corners and inner wheel housings.  I already knew I was in for a repair on the right side rear wheel opening, but as I soon discovered, the left side would not escape the same fate.  Looks like the scope of work between the left and right side of the car will be a virtual match.  Whoopee………

The “up” side to this discovery is that I had already prepared for most of this additional repair, so all I need is one more patch panel to cover this newly discovered damage.  As a bonus, I can purchase one single patch panel that will cover the left rear wheel opening corner patch as well as the curb damage on the front wheel opening (more on this in a future entry).

With clean(ish) metal to work with, I leveled the car on the chassis support posts and started marking all of the spot welds locations on the left trunk floor in preparation for removal.  This is where a bit of pre-planning helped quite a lot, as all of the spot welds are not easily accessible with the spot weld cutter.  Also, a secret to making the job go much easier was to cut away as much of the old panels as possible such that I was left with only the spot welded flanges to work with.  I chose to use my pneumatic sheet metal nibbler for this as it is quick and capable of maneuvering in tight spaces much easier than my air saw.

With the bulk of the left trunk floor panel out of the way, I cut the spot welds free and popped the panels out rather easily.  The two areas that require a different approach are the welds along the inner wheel house and along the lower quarter edge between the wheel opening and the rear valence area.  In the inner wheel house area, I marked and drilled the welds from inside the wheel opening and gently separated the panels with a thin putty knife.  On the lower quarter flange, I found I couldn’t approach the welds straight-on with my spot weld cutter due to interference with my rotisserie, so I sized things up and decided to carefully grind through each spot weld with my cutoff wheel so I could pop the flange loose without running the risk of drilling a hole through this rather narrow flange.

It’s worth noting that all of the welded flanges in this area of a Mustang have weld-thru seam sealer between them and this provides significant resistance to separation of the flanges even after the welds are cut.  Another caveat is that you can be absolutely sure that anywhere Ford put this weld-thru seam sealer between the flanges is now quite rusty.  There’s absolutely no escaping this fact and it’s one of those dirty little secrets that nobody wants to let out of the bag and unless you plan to completely disassemble every last welded seam in the car, this is something you simply must deal with.  This is one area that has me thinking a chelation “dip process” could be very effective.  But that’s another story altogether……..

With the left trunk floor out of the way, I removed the rear trunk floor flange with rather unceremonious application of my trusty Sawzall which allowed me to remove the small section of flange left attached to the rear subframe horn.  With all of the offending sheet metal now removed from the left side, I was delighted to find the left rear subframe rail in pristine condition!  If ever there was an automotive “miracle” this discovery just might be it.  For as much weather that this car has endured, and the state of the trunk floor in general, the fact that the subframe is in such good condition almost defies explanation.  Thank goodness for galvanized metal!  Here’s hoping the right side is just as good.

In the meantime, I will start grinding the spot weld buttons smooth, metal working the flanges flat and starting the quarter and outer wheel opening rust repairs.  I have also found a number of additional stress cracks and valence bolt hole damage that requires repair as well, so the next few weeks will be pretty full.

Though it's tough to tell in this photo, I have started by marking all of the spot welds that need to be cut to remove this trunk floor section.

Here is a view of the rusty mess and you can see some buckling evidence of the rear punt the car took sometime in it's life.  I have already scraped off the sprayed undercoating that lined a section of the inner fender in this shot.

The right side looks a tiny bit better, but this is the side where the rust has eaten through the outer skin at the rear of the wheel house.

After slapping myself around a bit, I sucked it up and rolled the car out to the drive for some sand blasting mayhem.  In the end, it was the best decision.

Looking back up from the trunk floor to the top of the left rear quarter, you can see there was absolutely no pant or primer on the majority of these surfaces.  We're gunna fix that soon!

I love my dad!  Always there to help and always an ace at everything he does!  He's the reason this job got done before dark!  As you can see, he plays the Sandman quite well!

Have I mentioned that stinkin sand gets EVERYWHERE?

After a short blast from the inside, you can clearly see the rust perforation in the right rear quarter.  No surprise.

I didn't blast everything totally spotless as I plan to do another chelation experiment very soon on the inner quarters.

I rather like this view.  It really looks like I'm getting somewhere.  Nice clean, solid metal in beautiful grey primer.  And then.......

.......ya get this by stepping back a few paces.  Quite a contrast and probably the best indicator of what the current job entails.  Once it's done, she should be nice and solid again!

SURPRISE!  After the first several spot welds were cut and the floor pulled back, I couldn't believe how nice the inner frame rails were!  However, I quickly found that cutting away the extra material with my nibbler made removal of the panel much easier.

How about that!?  No problem at all working with these rails!  Hopefully the right side will be equally good!

With the bulk of the metal removed before I started drilling out spot welds, it was relatively easy to get the welded sections out.  Here, the entire left trunk floor is removed.

Note that every place there was a spot welded seam (except on the galvanized rail flanges), the factory weld-thru seam sealer has promoted rust between the panels.  One of the "dirty little secrets" of classic Mustang restoration.

The last section I removed was the rear trunk floor cross panel that spans the full width of the trunk from apron to apron.  Again, I cut out the bulk of material with my trusty Sawzall and left only the spot welded section to remove.

Here is a good shot showing the way I support the rear frame rails in the rotisserie as well as the small section of material that remains to be removed from the rear subframe horn.

Here is the head-on shot of the rear of the subframe with all of the rusty metal cut away.  Nice!

And there we have it.  A pile of rusty crap that used to be a left trunk floor.

Tail Light Panel and Trunk Floor – Part 1

The last major structural repairs that must be completed on my Boss 302 before “regular” restoration work can commence involve replacement of the trunk floors, rear tail light panel, rear quarter extensions and repair of the front trunk floor/axle tunnel flanges along with a small amount of rust repair on the right rear wheel arch.

It sounds so simple to condense it down that way, but this amount of work is quite extensive and will take a few months to complete, if not longer.  In fact, as the pace of restoration work has slowed over the last few weeks with non-Boss related activities, the chances are that this particular project will continue deep into the winter before it is complete…….so let’s get started!

At one point, before my ownership, this car was the “meat” in a traffic accident sandwich and suffered light damage to the rear and somewhat heavier damage to the front sheet metal.  Luckily, the rear quarters were not buckled in the incident, but the tail light panel, and rear center trunk floor and lower valence were folded noticeably and the temporary repairs were very poorly executed.  The end result was rust invasion between every panel such that the only way for me to repair them was total panel replacement.

I spent several weeks studying the landscape of this repair, carefully mapping out every step I would take in making sure the end result would be well-fitting, straight and pristine sheet metal.  Once I was comfortable with where I was going, and the repair panels were in hand, I was off to the races.

One significant change to my plans was actually a welcome reduction in the scope of work I had envisioned.  The lower rear section of the right quarter panel was where the rust repairs were required.  Originally, I planned to install a complete patch panel along the entire lower rear quarter panel section, however on closer examination, I discovered I had a lot of good metal around the area and the repair could be condensed to a small patched area instead.  This leaves the vast majority of the original quarter panel completely intact which is a bonus by almost any definition.  The one caveat to this repair is that it will have to be done while I have the right side trunk floor out to allow proper access to the back side of the repair areas.  No biggie, just planning.

With a solid plan in place, I pulled out my trusty red paint pen and set off marking the cut lines that would allow me to efficiently remove the bulk of damaged sheet metal in the shortest time.  Next, I squared and leveled the chassis on the rotisserie and placed my jacking posts under each rear torque box to maintain this position and to provide substantial support to the chassis while the repairs were being made.

Using a white paint pen, I started marking the spot weld locations that would need to be drilled to allow the fender extensions and inner jack mount, spare tire mount and rear bumper brackets to be removed.  Then out came the “screaming wheel of death” and the sparks started to fly!  After about a half hour and three cutoff blades, I had the tail light panel out of the car.

With room to work, I could now drill the spot welds and remove the jack and spare tire mounts, both rear bumper brackets and both rear fender extensions with relatively little trouble.  This also allowed me plenty of room to scrape the little bit of remaining undercoating off the inner rear quarter panels to make all future work even easier as well as provide a nice smooth surface for Dynamat adhesion when the finish work begins.

I cleaned up and straightened the fender extension flanges with a little angle grinder work and some hammer and dolly taps and began fitting the fender extensions using the factory body locating holes in each quarter panel flange.  I was pleasantly surprised at how well the fender extensions fit (for a change) and I like the one-piece design of the new panels over the rust prone 2-piece design of the original extensions.  Of course, restoration purists will throw up all over this idea, but from a practical perspective, the idea is a good one and I am glad for it in my case.

I spent quite a bit of time making sure the fit of the new quarter extensions was as good as it could be and clamped them in place just as if they were being installed.  Then I carefully marked each spot weld location so I could remove the e-coat only where the welds would be needed.  Did I mention you can never have enough good vise-grip style welding c-clamps?

And that’s where we are.  The next phase will be to remove the trunk floors and start preparing the flanges for the new parts.  In there somewhere, I will start the process of fixing the front trunk floor section as well.  All in all, there will be a lot of tack welded and Cleco’d pieces put in place before the repair work can be finalized.  Off I go!

Front trunk floor/axle tunnel is pretty rough.  Rectangular hole in the upper left is the area cut out by the factory for the staggered shock mount.  I will be repairing this section with new metal and eliminating this hole as it is not required with the rear suspension I am using.

Right side trunk floor is a mess even with the jack and spare tire mounts already removed.  You can just barely make out the buckling at the very rear edges of the panel from a previous bump.

Left side trunk floor is pretty rusty and wrinkled as well.

Using my red paint pen, I marked the locations where I would cut the tail light panel and quarter extensions with my cutoff wheel.  Here is the left extension marked for cutting.

Right side fender extension with cut line marked.

Right rear corner cut line.

Left rear corner cut line.  Some of the wavy sheet metal is visible here.

The white freckles in this shot are spot weld locations marked with white paint pen.

More spot welds located.

Spare tire bracket and jack brackets removed.

A few minutes with a cutoff wheel and the rear tail light panel was out!

With a little metal work, the rear quarter extension flanges were nice and straight.  This allowed me to fit the extension panels quite nicely.

Quarter panel extensions are aligned using the body alignment holes.  These are the three larger holes in the flange that are used when mounting the extension end caps.

As fitting comes closer to perfect, several clamps are required to prevent movement when working on specific areas.  You can never have enough vise-grip type welding clamps.

Right side extension was fit in the same way as the left.

This is a good shot of the fit I am always trying to achieve.  When spot welded in place, this panel will fit every bit as well as the factory parts.

Lower on the outer edges, the fit is equally good.

This is probably one of the trickiest areas to fit on the rear extensions.  Patience and clamping helps as you work the flanges to get the fit as tight as possible.