Tuesday 24 March 2009

Cowl Repair and Front Suspension Brace

Hi again.
This will be an evolving post as I don't really know how long this particular stage will last.

As you can see from the photo below, my cowl had plenty of rust in the usual places once i'd removed all the guard support flanges (and removed layers of silicon filler!).
My approach for this stage is as follows.....
  • Cut away the upper cowl in a way that it can then be "removable" - as per Australian Falcons of the early 1970's (and no cuts/joins will be visible). A trap with Mustangs is that as the upper & lower cowl panels are installed as a welded unit, you can never get adequate access to properly rust-proof them at the welded joins (or at least not without great difficulty!). By making the upper cowl removable (attached with just a few screws), I can apply a very effective rust treatment and always have access to this area when required (like removing leaves from vents & fan blades).
  • Fix any rusted areas & "rust proof" the cowl as described above.
  • Install a full-length section of box-tube steel across the rear of the engine bay to provide a solid foundation for the lower (and removable upper) cowl, firewall & new front suspension bracing.
  • Install the new rear engine-bay aprons.
  • Install the new cowl "kick panels" (the side panels that run from the door-hinge frame forward to the firewall).
  • Install a new firewall - although this will be only partially completed as I need to test fit the engine (sitting as far back as practical) in order to fabricate the final piece.
Anyway, below is a photo of the original metal after the upper cowl was removed.

Notice the rust holes in and around the vents. This car must have leaked like a sieve when it ran in the wet!
And below you can see the metal I had to remove to get back to a reasonable foundation.
You can also partially see (at the bottom of the photo) the custom box-tube section I had to fabricate that will fit the contour of the lower cowl. It's sitting there after countless trial-and-error "test-fits".
And below you can see that new "cross member" a little better but with the cowl repair well underway. I'm using 1.5mm zinc coated steel sheet for these patches.
And now you can see the cowl vent "stacks" have been fabricated and the new cross-member is also in place. I've also started to trial-fit the rear aprons as they finally have some metal to attach to at their rear ends.
And for those that are interested, that custom cross-member was a very tricky piece to make and to "get right". It needed to curve in 3 dimensions, be symmetrical and fit the cowl such that there were no gaps too wide to be welded.
This video may provide some idea of what is involved in the part of the repair (plus show just how nice a rotisserie is for making this project a little easier!).
One thing i've realised now that i've got this far...... I think i've finally reached a point where I no longer need to repair major rust problems. It's all "finishing off" work from here - hooray!
I'll modify & add to this post as I proceed.....

Friday 13 March 2009

Front Frame & Rotisserie Support

Readers of earlier posts will know that I had some serious rust damage in the front frame directly beneath where the battery used to sit. I had been avoiding this fix as it was always going to be awkward unpicking the various spot welds that the standard Mustang has in this area (with so many suspension brackets), not to mention the custom metal-work needed for fit a new repair piece.

However, I eventually received my repair panels, so I cut out the old rusted section until I had a solid foundation and then trimmed the repair pieces back to match the "gap". As can be seen here - it's all fixed now! The lower edge of the fender apron is yet to welded back on when this photo was taken.

The shot above is a much better sight than the equivalent photo in an earlier post (taken when I was dismantling the car).

The photo's above and below show how the repair pieces are a superb fit (once you trim them back to match your requirement).

One nice surprise was that the rust caused by the battery leaks over the years only affected the area under the battery. I found "full thickness metal" in the old frame from just beyond the sway-bar mount. I made sure the patch grafted to the old frame at a diagonal angle for a strong bond. Needless to say, the old and new frame were "rust converted" and "rust protected" inside and out.
I needed to repair the front frame (specifically the mounting points for the front bumper-bar) so that I could remove the remaining section of the space-frame and re-mount the rotisserie to these bumper mounting points.
The space-frame needed to go so I can complete the fixes needed to be done to the cowl & firewall, plus clear room for new front suspension bracing I will be fabricating. So..... the front of the car went back up on blocks, the front space-frame was cut out, new mounts were created on the rotisserie, and then bolted to where the front bumper normally mounts.
You can see the setup in the shots below.


Note the huge "air gap" above the front rails with the firewall, rear fender aprons & outer cowl/kick-panels removed. I've put in the temporary upper piece of box-tube just so this gap doesn't shift as the body is rotated during work.
And here you can start to see the rust in the area where the cowl, dash & firewall all join along a spot welded seam that runs right across the engine bay. This seam will be cut out and replaced with a curved length of box-tube. Once the seam is cut out I can fix any rust problems as well as using the box-tube as a more solid foundation for the firewall & (under) dash panels as well as a platform for stabilising the front shock-towers.

But that will be shown in the next post!