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.