Once I chased the strap around the pan back to the start I used a hack saw to cut the tail off as shown in photo 1. Still haven't welded anything solid. I tested the bottom of the pan for fit and found it was pretty close. I tacked it in postion on the long straight side and using a body hammer and screwdriver, slight adjusted the front and back ends to alignment. If you are careful in tacking the strip vertically, and the accurate initial severing cut and accurately sheared filler piece almost guarantee that, then the pan cap should fit very closely. Photo 3 shows the side with all of the indentations needed a little adjusting but was still not bad.
Once I was happy with the fit I used my oxy/acetylene torch to gas weld the entire bottom seam and as much of the top one as possible before removing the pan to do the body work necessary to line up the last side. Body hammer & dollies and ball-peen hammers were used. Photo 3 shows the finished welds.
Now using vice grips of various shapes I started spot MIG welding the filler strap to the long straight side of the flange. I placed the tacks every 3 or 4" (Photo 1). Photo 2 shows how I used heat to get the bends correct on the corners. I also used heat and tacks to walk the metal around the bolt clearance dips in the pan sides as in photo 3.
My trusty old Hydro has a nasty habit of leaking a LOT of fluid when it sits for any length of time. This is a characteristic of 50s Hydramatics - there is a check valve in the torus that is supposed to keep the fluid out of the tranny case but it goes bad very quickly. That lets all the fluid in the huge torus drain into the tranny case, build up past the output shaft, and leak out the weep hole in the drive shaft yoke. I have been wanting to deepen the pan to hold the excess fluid and not leak it out so today I decided to bite the bullet and do the deed! This process can be used on deepening engine oil pans too.
I used a thickness gauge and found that my pan is made of very heavy 14ga, 0.064" steel. I had my local steel shop cut me a 1 1/2" x 48" piece of cold rolled mild steel. Since my pan is about 9" x 12", that gives me almost 3 extra quarts of space. The equation is Length X Width X Height / 231 = gallons. In my case 12" X 9" X 1 1/2"/ 231 = 0.7gallons.
I needed a very accurate, very level cut on the pan so I could as a 1 1/2" filler. Photo 1 show how I did it. I laid a Sharpie pen on a piece of 1/2" plywood on the shop floor. The line had to be high enough so I was in the straight side of the pan and had room to weld but low enough to miss the drain plug that came stock in these trannys. Then I simply rotated the pan on the flat floor against the tip of the pen and got my perfect mark. I used an abrasive cutoff tool to cut the pan in half following the line as shown in photo 2.
Now the key to a good job; bolt the flange to a dummy block as in photo 3. I have an old hydro that I used for parts that served the purpose perfectly. This is critical - it is impossible to avoid fatal warping of the flange if it isn't bolted down solid.
The last panel I needed to finish the interior was the dash panel. There are commercial ones available but they are expensive and would have to be extensively modified to fit my customized application. It was easy to make my own. Figure 1 shows the construction method. I first made the two flat side panel from 1/8" luaun plywood and attached them with Auveco panel clips to the two sheet metal "C" channels that Chevy spot welded on either side of the center hump.Then I waxed the aluminum foil insulation with PartAll mold release wax and laid on about 3 layers of fiberglas, overlapping the boards a couple of inches. Once hardened, I remove it and put a 'glas strip on the inside overlapping the boards making it a permanent single piece unit.
The second shot shows it in place, Bondo'd, ready to sand and upholster. I will remove the Auveco clips (impossible to install blind) and screw the thing to those "C" channels on the firewall so no fasteners show in the engine compartment. The ends of the panels are wedged in place by the kick panels so no fasteners needed there.
Photo 3 shows the "C" channels I am talking about for those unfortunate few out there who don't own an AD pickup!
This is the final result! Photo 1 shows the rear boxes pried off the speaker board the aluminum foil removed, the staples ground away and ready for installation of mounting screws. This shows the complicated shape of the boxes that would have been difficult to make any other way.
Photo 2 shows the front door panel speaker boxes attached to the rear of the panel.
One small problem is that I was unable to completely saturate the cloth with resin from one side. Once the resin set and I pried the bucks out, I could see fuzzy cloth on most of the interior. No teal problem, I just painted on a coat of resin on the inside and once hardened, the boxes were bullet proof!
I plan on leaving the Barbie pattern there for the next owner to wonder about!