Floor area sand blasting & a little teaser

I have come to realize one thing after this weekend:  God must love Boss 302s!  How do I know this?  Because he was kind enough to hold off raining all over my nearly-nekid  car until Dad and I managed to get her safely inside the shop, and all our blasting sand recovered and put away.  Yep…..after two solid days of slinging sand all over creation, I was rewarded with a host of clean metal that was refreshingly solid and surprisingly lacking in the heavy rust damage that was present in so many areas of this car.  I am very happy to say that I have reached a point where the major rust damage finally has been removed and getting the new floor welded into the car will have the car about 65-70% structurally complete.  Still a lot of complex work to go before “normal” restoration work begins, but pretty significant progress nonetheless.

At this point, the car is ready for me to treat the bare surfaces with phosphoric acid, and start welding in the three major patches required before the floor is installed.  This alone will take a few weeks to complete as I still have to fabricate the rear floor transition patch.  In the meantime, I will repair the toe boards and clean up some spot weld cutter divots in the front sheet metal flanges.  From there, I will coat the inner rockers and firewall area with Zero Rust for protection and move to the rear floor sections needing repair and straightening.  Again, lots of work, but great to know that progress is finally starting to show.

For pure entertainment, I also mocked up the Heidt’s four-link forward bracket assembly.  This is the major structure added to the car that functions as the forward mounts for the upper and lower trailing arms.  While the kit is marketed (and many magazine articles show it) as a “bolt-in” kit, I find this is not likely to be the case.  The subtle differences in the 69-70 chassis dictate some slight modifications will be required to make the brackets fit perfectly.  In addition, some gaps exist where the bracket saddles the frame rail that are considered “normal”, but that ain’t so around here.  Since I plan to weld these structures into my car, I insist that they fit well, while gaps like this may be fine for bolted installations, it won’t be tolerated for a welded installation.  So…..more fab work ahead...........as usual.  Did I mention I think God loves Boss 302s?



Here's the car ready for a day of blasting. 



In the pre-blast inspection, I found two more stress cracks in the chassis.  This one is directly beside the axle snubber pad at the rear of the driveshaft tunnel.




Passenger side lower torque box and spring mount area looks very nice after blasting.  The water-spotted look of the torque box is actually the patina the galvanized metal takes after blasting.




Trans cross member and passenger frame rail cleaned up quite nicely too.




Driver side inner frame rail and cross member also looks good.  Note the galvanized material used in the cross member.




More galvanized metal.  Here you can see the distinct difference in finish of the blasted galvanized metal of the frame rail and lower torque box versus the plain steel of the leaf spring mount in the center of the image.




Passenger side of the axle tunnel looks surprisingly solid.  A little clean-up in this area will work wonders.




Here is the driver side axle tunnel.  As you can see, I didn't bother blasting the section of the floor transition I plan to remove and replace with new metal.  No need to waste the sand......




Driver side inner torque box is excellent!




Inner frame rails cleaned up very well.  Spot weld cutter divots will be welded up and ground smooth before the floor goes in.




The firewall also cleaned up quite well.  Still needs a bit of wire wheel work to get everything clean, but that part is comparatively easy.




Trans cross member is really very solid.  Again, a galvanized part.




I couldn't resist mocking up the Heidt's frame mounts.  Here's how they tuck into the original leaf spring pockets.




While this 3/16" gap between the frame rail and frame bracket may be considered "normal" for bolted-in Heidt's four-link conversions, it is unacceptable to me.  This will be filled with a steel "shim" welded to the frame a base and this bracket will then be welded to it and the frame as a solid assembly.




On 69-70 mustangs, the inner wheel houses are actually slightly farther inboard than in earlier models.  This creates a slight interference to the Heidt's frame bracket.  A slight bit of massaging of the metal will solve this problem quite quickly.




Another look at the gap that I will fill before installation.



Driver toe board patch fab and rear floor removal completed

The weekend proved to be quite productive after a pretty slow last few weeks.  When I left off, I had yet to remove the damaged toe board section from the driver side.  I felt a little more thought was required before I cut out the section and the end result was a slight change in how I would cut the inboard side.  Once I settled on the method, I marked the general shape on the existing toe board with soapstone and set about making the toe board patch mirror the shape exactly.  I have learned it is best to make the patch panel first, and then trace the outline on the original part so you can precisely match the cut to the panel that will be welded in.  With this technique applied, I marked the section to be cut, drilled the spot welds that were involved and carefully cut just inside the cut lines with my panel cutter (a.k.a. the wheel of death).  The whole process took about 30 minutes and as luck would have it, the panel fit perfectly.  Now that both toe board patches are fabricated and the rotted metal cut out, I set them aside until I can sandblast the areas for proper preparation for welding.

Next on the agenda was to remove the remnants of the floor flanges along the rocker boxes and then move on to removing the floor sections that remained at the rear along with the upper torque box covers.  Fortunately, the rocker flanges came out without much fuss, leaving the majority of the weekend to be dedicated to removing the rear floor sections.

This rear floor area of a Mustang can be quite tedious to remove because there is a high concentration of spot welds in a relatively small area and the floor flanges that mate to the inner wheel houses actually turn down under the car where the rest of the floor flanges turn up toward the inside of the car.  I had my hands full trying to locate each spot weld given so much of the metal was badly rusted making the spot welds almost impossible to see.  However, with a little patience and a nice variety of tools at hand, the final section of the old, rusted floor hit the floor with little protest.

I have to admit I was very nervous to uncover the rear subframe and torque box cavities as I was sure they would be destroyed by rust.  Well, I WAS WRONG!  What I discovered in both locations was clean, solid metal that would require a little massaging to get straight, but no replacement!  Luck just doesn’t describe it…….

The joy at this discovery was tempered somewhat by two “downers”.  The first I somewhat expected, but was disappointed at the severity.  Specifically, the driver side axle tunnel transition area where the floor meets the axle tunnel was much more heavily damaged by rust than I had suspected.  The other was relatively minor stress cracks at the rear drive shaft tunnel area.  Yet another indication of the abuse this car endured in its earlier life.

I’ll now set off to make a patch panel for the damaged axle tunnel transition and get it ready to weld in and repair the stress cracks at the rear of the tunnel.  Somewhere in there I am keeping my finger on the trigger of the sandblast gun with an eye on the weather………COME ON SPRING!

Removing the rear floor sections is tedious.  Lots of spot welds in a small area and some rather difficult to get to with a cutter.  Also, I was not confident I would have much to work with under that torque box cover with all of the rust in the floor and the perforations in the cover itself.  Was I wrong about that!

Other than light surface rust, the underlying metal in the passenger rear floor area was excellent.

The driver torque box cover was the better of the two, yet I still wasn't sure what I would find underneath.  To my surprise and delight, the torque box was pristine and had almost no rust evident at all!  The white powdery surface is actually from the galvanized metal itself and will clean up nicely with a light sand blasting.  Both torque boxes will get coated in Zero Rust paint before reassembly.

Another surprise was the equally good condition of the driver subframe. 

Bolstered by the good news on the driver side, I removed the torque box cover on the passenger side with fingers crossed.  I was astonished that it too showed to be in equally good shape!

And the same for the passenger subframe too!

My enthusiasm was tempered a bit by the more extensive damage to the flange just at the transition to the rear axle tunnel.  Quite an extensive patch will have to be fabricated to repair this section of the floor pan.

My final disappointing discovery was two rather significant stress cracks at the top corners of the driveshaft tunnel where it meets the axle tunnel.  I have discovered this is a common stress crack area in cars that were raced heavily or abused.  No surprise there......

From the floor to new Heidt’s – New stuff is the BEST!

Progress has been a little hard to come by lately, but I am happy to say, new stuff has been procured!  Over the past few weeks, I have managed to pick up a new floor, seat pans, rear torque box covers and the latest Heidt’s four-link coilover rear suspension system along with their subframe connectors.  Kinda feels like Christmas all over again!

As I mentioned in an earlier post, my car will ultimately ride on a full coilover suspension system.  The front suspension will be a very nice setup from a local company owned by a fellow named Shaun Burgess called Street or Track.  Shaun has developed one of the finest coilover front suspension systems available for the Mustang and it is also one that requires the least modification of any available (it’s practically a bolt-on affair).  Check it out here:   Street or Track Coilover Front Suspension Kit

The rear suspension is a bit more involved and I have chosen to go with the Heidt's Hot Rod Shop 4-Link Coilover Kit.  The Heidt’s stuff is extremely well made, easy to install and maintain and it works pretty darn well.  While they market the kit as a bolt-in, I will be welding the system into my car as I hate the “bolted-together” look and I want it to blend smoothly into the rest of the undercarriage.  Once the bottom of the car is sprayed with SEM bed liner coating, the whole setup should look as close to factory as you can hope for.  I’m excited!

I stopped off at NPD and picked up their top-of-the-line one-piece floor along with a pair of new seat pans and rear torque box covers.  The parts look quite nice and I am looking forward to being able to install them once the weather allows for some sand blasting.

When this load of stuff showed up, I was like a kid with anew bike!

There it is!  The 4-link rear suspension I have been waiting for!

......and a set of subframe connectors to go with it!

All unboxed and set out for inspection.  The Heidt's stuff is very nice.  All the steel parts are laser cut and look gorgeous straight out of the box.

The weld quality on every piece is second to none.  These frame brackets appear to be robotic MIG welded and are fantastic.

The 4-link brackets are TIG welded by hand and look very nice.

More very nice TIG welding on the lower coilover mounts.  Also, notice how smooth the laser-cut edges are on every part.  It's almost as if every edge was polished.

Floor removal, toe board eval & frame rail straightening

Now that my taxes are filed and I'm square with the Fed for one more year, I was able to get back to business on the Boss.  With the cowl complete, the next step was to begin the process of repairing the floor area and all of the associated areas that required attention.  There is nothing “pretty” about this phase of work and the pictures certainly reflect this, but with this ground work in place, the end results will ultimately show the effort.

I decided to tackle the removal of the floor pan by first removing the seat pans.  As previous pictures will show, the floor in my car was a mess, with little salvageable material left to use.  As such, I didn’t need to be especially frugal in the removal of the bulk of the floor pan structure, so out came the smoke wrench (a.k.a. oxy/acetylene torch) and after a few minutes, the seat pans were history.

With more room to work, I could now concentrate on getting the floor pan out of the car.  Here again, there was nothing left to save, so I decided to employ my trusty recip saw for the removal of the majority of the old floor pan.  I decided I would take the floor out in three pieces beginning with the center and leaving the front and rear sections for later.  Mainly, I did it this way to make it easy, but also to allow a more precise removal of the front and rear sections where considerable spot weld cutting would be required.

Once the center section was out of the car, I concentrated on removing the front section attached to the front frame rails, the transmission tunnel brace and front toe boards.  There were a lot of spot welds involved here and I was once again thankful for the efficiency of my Blair spot weld cutter.  After a few hours of work, I was able to carefully peel the front floor section away and have my first serious look at the frame rails and toe boards.

As I have mentioned on numerous occasions in the past, the abuse this old car has taken in its life is hard to imagine.  Almost everywhere I look are signs of an extremely hard life and the lower surfaces of the frame rails were certainly no exception.  First off, Mustangs were never designed to tolerate jacking on the frame rails.  As a unibody car, they were designed to be jacked up along the pinch seam that runs along the bottom edge of the rocker boxes.  This is the area where the car is especially strong and capable of supporting the weight of the car without damage to the structure.  Somewhere along the line, someone was very enthusiastic with a bottle jack of some kind, and had managed to severely damage the bottom of both frame rails with deep, quarter-sized dents the exact shape of a bottle jack pad (ugh!).

I spent several weeks pondering the most effective way to repair these areas, particularly since the frame rails were in such good shape otherwise and had miraculously managed to avoid the heavy rust damage the remainder of the floor had endured.  In the end, I decided to basically use the old hammer-and-dolly technique, expect the dolly was going to be a piece of flat steel plate on the end of my frame jack post pad and the hammer was going to be a combination of 2-lb sledges and a simple forming tool I made from some spare ½” plate.  I knew ahead of time I wouldn’t be able to remove the deep scars from the bottle jack pad, but I felt I could get the frame rails straight enough that a thin skim of filler would be all that was required to make them perfect again.  I am happy to say the results were even better than I expected.

With the frame rails in good shape, I turned my attention toward a comprehensive evaluation of the toe boards.  I knew I would need to replace the obviously rusted lower edges of the toe boards, but wasn’t sure how far up the firewall I would need to go to get back to good metal.  As it turns out, the repair of the passenger side would be quite minimal in scope and the driver side would be quite manageable as well.  I wanted to keep the amount of weld seams inside of the trans tunnel to a minimum such that the metal finishing would be minimum and the least amount of filler would be required to make these repairs invisible.  Looks like I just might get my wish!

Next up, I will start preparing the toe board repairs and tidying up the frame rail and transmission tunnel brace flanges.  I will also remove the remaining flanges from the old floor as well as the rear floor section under the back seat area.  Somewhere in there, I hope the weather breaks enough to get some sand blasting done in these areas as well.  That should really make everything not look so much like a junkyard dog…….c’mon SPRING!

A few minutes with a torch and the seat pans were outta there.  This made the rest of the floor removal quite easy.

My recip saw handled the bulk of the floor removal with ease.

I left the front section of floor in place as there were numerous spot welds that required a rather precision approach to removal to ensure minimal damage to the parent structures underneath.

After a few hours with the spot weld cutter, the front floor section was removed without much fuss.  This allowed a much more comprehensive inspection of the inner frame rail surfaces as well as the toe boards.

Here you can get an idea as to the extent of damage there was to the bottom surfaces of both frame rails  from the use of a bottle jack.  With such structurally sound frame rails, I had to figure out how to repair this damage rather than replace the rails.  This is the passenger side"before" shot.

Using the jack posts I made during my cowl replacement, I fashioned a flat steel "dolly" that gave me a hard surface to work against when reshaping the lower frame rail surfaces.  The adjustable jack post on the opposite side of the car was extended to provide slight pressure on this assembly to provide a solid work surface.

While generally ill-advised, I used a small 2 lb sledge as the first means to get the damaged metal moving.

For the finer work, I made a simple bucking die that allowed me to restore the shape of the corners and edges of the frame rails as well as the bottom.

By turning the bucking die sideways, I could rather easily restore the lower frame surfaces by simply walking the die up and down the length of the fixed dolly until the surface was nice and flat.

Here's a rather poor shot of the driver side frame rail during the straightening process.  You can easily see one of the remaining heavy dents just to the left of the trans tunnel brace flange that has yet to be removed.  The jack post and dolly can be seen in position at the far right of the picture.



Here is the driver side frame rail after straightening.  Notice there are no more nasty, jack-induced dents in the lower frame surface!  A small amount of All-Metal filler and these surfaces will be nice and smooth.



Here's the passenger side frame rail after repair.

After careful examination of the exposed rust damage, I marked the passenger side toe board using a bit of soapstone.  Nothing too extreme required here.

Similarly, the driver side toe board repair section is surprisingly minimal given the extent of rust damage that was in most sections of the original floor.

Cowl Panel Replacement - Episode 6: Touchdown!

It’s kinda funny what inspiration a brand-spankin new mig welder can give a fella.  When I last left off, I had fit each cowl end enclosure to the cowl and clamped them into place. Having nailed the fit on both ends to near perfect, I prepped each one for final welding and refit them one last time and clamped them securely into place.  I was absolutely chomping at the bit to try my new Lincoln mig welder out after practicing my plug weld technique on some scrap sheet metal.  With some easy adjustments to my technique, I was able to crank out respectable plug welds and I felt really good about the prospects of getting the end enclosures welded into place and putting paid to the cowl replacement project.

With a few butterflies in the pit of my stomach, I set off anchoring the corners of the enclosures with solid plug welds right out of the box.  I could feel myself smiling like a fool under my welding helmet at how well the machine worked and decided Lincoln didn’t paint their machine Ferrari red by accident!  Man does that thing perform….!!!

It seemed like no time at all and I had both enclosures welded in and I was grinding the welds.  Each weld was far less bulky than my old welder could produce and they all cleaned up quite well with a little grinder work.  In the matter of a few hours, I looked up and realized I had completed the cowl replacement and lived to tell the tale!

With all of the welding completed, I finally had the opportunity to evaluate the entire job more critically.  Most obvious was how solid and tight the whole structure felt.  With an actual structure back in the car, it was really amazing the difference in how the car sounded when rapped on with the knuckles.  There’s something oddly rewarding about that solid “pop” when you “knock on the door” on a new structure like this.

With the hard work out of the way, I just need to touch-up the interior of the end enclosures where the weld heat damaged the Zero Rust paint and then seam seal the remaining flange seams once everything is dry.

Next on the agenda is the removal of the floor pan, toe board repairs, lower subframe straightening and preparation for a new floor pan and seat pans.  Following that, I will be ordering subframe connectors (RM-102), chassis brace (RM-023) and 4-link rear coilover suspension (RM-101) from Heidt’s Hot Rod & Muscle Car Parts.  I’ll also be on the hunt for a 72-74 Ford Torino rear swaybar to complement the new, modern rear suspension while giving the car maximum wheel width allowance without wheel tub modifications.  Just a little hint into what’s on the horizon……and it ain’t likely what you might expect.

I went a little overboard on clamping the end enclosures perhaps, but it ensured the fit was near perfect.

Even between clamps, the flanges were straight and tight before welding.

The top flange is effectively the guide for the rest of the panel.  Good fit here is critical.

Here is a look at the fit in the top rear corner of the end enclosure.  Beautiful!

From the first arc strike, it was obvious my new Lincoln mig welder was light-years ahead of my old, fussy mig it replaced.

Here is the driver side end enclosure welded in.

And here is the passenger side enclosure fully welded.

Driver side welds ground smooth.

Passenger side welds ground smooth.

Here is the back side of the driver enclosure.  The fit here was truly excellent.

Passenger side rear of view of the end enclosure after welds were ground smooth.

Here is the finished driver side upper rear corner.  The fit here really couldn't get any better.

A faked aerial shot of the finished cowl.  On to the floors!