Firewall Replacement Part 2

This shot is looking into the part of the vent cowell that is still on the truck. The triangle metal flap with the reflecting shine on it is a water deflector. It keeps rainwater from running down the inner wall and coming through the vent under the heater and, on the other side, under the parking brake pedal. On my initial build of my crewcab, I patched some rust in the cowell and forgot to replace the deflector. When it rained or when I washed the car, my floor always got soaked. Here, I painted the surface with POR15. I forgot to replace the seam sealer in this area. I will have to sneak it in there later because...
...I started welding in the new part. So, that little hole is now all I have for access for the sealer. This is the outside below the windshield. It will be covered by the cowell grill panel that goes between the hood and windshield. The threaded stud and the threaded hole support the top of the driver's fenderThis is the inside below the windshield, driver's side. The bracket supports the parking brake assembly.
This is the outside on the driver's side looking at the area next to the wiring harness plug. This pic must be upside down, which would make the stamped-in numbers upside down if I turned it over. I decided not to change the picture because it is a pain in the butt to do so.

Maybe I will keep it this way so I can view the Cummins.

Not. This is a tough look. I keep telling myself that I did not just destroy my truck. I also wonder if it would have been easier to haf just cut the A-pillars and the floor and grafted the new on that way. It's a toss-up. If I had done that, then the front cab mounts would hav been utilized and the quality of my welds ay become a safety issue. Huh, sounds like a serious lack of confidence.

Kind of empty looking.
Hey look, twins.
Here is the firewall out of the donor. I left the wiper motor and linkage and the brake booster onit. Why not. It is newer than the original stuff, and, sticking with the theme, the wiper motor will, guaranteed, be compatible with the delay system built into the wiring and tilt column I will be using.
Here is the driver's side clamped into place and trimmed to fit with about 1/16" gap in most places.
The passenger side.
My worst fitment issue. Som filler will be needed, but at least it is out in the open, instead of burried down in the hole like the patches. All-in-all, I feel much better about this repair than a bunch of cruddy patches.

Patches? We don't need no stinking patches.

Unconfortable with and, frankly, sick of the patches, I ventured down a new path today. I made the decision to give up the patching and replace the whole firewall. After grinding away all the gobbed on seam sealer with a wire bruch on the 4" angle grinder, I exposed this seam that runs all the way accross the cab where the floor panels meet the firewall. I plan to cut the firewall just above the seam about a quarter of an inch.
Since my donor firewall is out of an '89 pick-up, I am not only eliminating the rust, but I am also prepping the ramcharger to accept the newr style wiring harness and heater box. The harness and heater bow will make the transition ti the '92 style dash a matter of screws and bolts. To the untrained eye, it will liiok like the '92 dash and instruments were in the truck since 1977.

I also exposed this seam next to the kick panel. I will also cut 1/4 inch into the firewall with the cut-off wheel in the air grinder.
Here I have made my initial cuts. The key-hole shaped hole is where the parking brake cable passes through the floor.
An hour and three cut-off wheels later, the firewall is loose,
Another shot from the other side. Prior to cutting this out, I "practiced" on a 1989 half ton gasser that I bought last summer. I bought it to supply a transmission for my 1989 ramcharger that is now for sale, for the cool, super-heavy-duty bumpers that were on it, and to be a sheet metal donor. Eventually, I will make a utility trailor out of the bed and frame. Currently the engine and transfer case are up for sale.

Trouble with the patching.

Wow, I am glad this photo is blurry. I know people who can weld. Apparently I am not one of them. The face of this patch was not too bad. It had easy enough access, but the patch extends behind the brake pedal/steering collumn bracket. Inside the cowel the surface is rusty and access is limited.
This shot shows some of what I am dealing with. What the shot does not show is that the camera is peaking theous a 1 1/2 by 3 inch hole. It also shows how bad my patch fit was in the hard to reach places.
Some of the welding had to be done through the 1 inch wiper post hole. Not enough light got out of the box to darken my welding lense. Flashed the old eyballs a few times. Got to get beyond this frustration.

To deal with the cowel rust, I needed donor sheet metal to graft in in place og the metal I cut out. I could have shaped new steel to form patches, but I have part of a cab from the '93 donor vehicle that gave up the power train for this project. This half cab is the full extent of the sheet metal that was on the truck when I got it.
Looking over the shape of the metal, the '77 and the '92 are virtually identicle, so I will use pieces of this red cab to make patch panels for the Ramcharger.
Using the sawzall and way too coarse of a blade, I hacked a big chunk of the firewall and cowel out. I debated removing the whole firewall and replacing the one in the rc with it. That would give me the correct hole for the style heater box that would fit the style dash I am using. Specifically, I am talking about the heater controls and ducting. I have not yet looked to see if the newer style controlls will work with the old heater box. Nor have I looked at how the ducting will work. If I need to, I will cut the firewall to fit the new style heater and be done with that issue.
I did not take any pics of the precess of laying out and cutting the patch panel. I basically just took some rough measurements and cut it out a litle too big, on purpose. Then i held it in place and marked where aditional cutting needed to be done. i did the cutting that I could reach with a cutt-off wheel on a die-grinder. The parts in behind the column/brake pedel hanger, I did with a 12" blade in the sawzall. This final pic is the finished panel in place. Since, I have welded the top edge and the hard to get parts behind the bracketry. Some of the welding I had to do through the hole where the wiper post comes through the cowel. It is not easy to get to. For the welding, I started by stitching at about 3/4" intervals, then, since I am not worried about warpage, I filled the space between the stitch welds all at once. Hopefully, I will finish this and the small patch tomorrow and I can start putting the dash in. Along with the heater issues, I will also need to change the rectangular hole where the harness plug passes through the firewall. And, yet to be resolved is the compatibility between the old style fuel guage sending unit and the new guage. I am guessing it will be a non-issue. Famous last words.

When I was cleaning up the ramcharger I found that there was a couple inches of sand under the cowel panel where the heater and vents get the outside air. I am talking about the space under the grills below the windshield where the wiper linkage lives. Being sandy or silty, it laid down there smoothly and I was unaware how much was there until I started vacuuming it out. Then I saw all the damage it had caused. I knew this was something I could not live with, so I pulled the dash out to get to the rust for repair. This is a shot of the firewall below the left side of the windshield. The bolts in the oval hole are to the upper door hinge.

This one was easy to cut back to solit metal. The lower square hole in the background is where the dash wiring harness passes through the firewall and meets up with the underhood harness. You might remember that I was planning to keep the old style dash and harness in the cab. Being forced to remove the dash really saved me a lot of future grief. The wiring harness under the dash was cobbled-up and would have been nothing but a headache to make work.
This is more damage. Low center in the pic is the trottle petal bracket. Left is the bracketry that supports the brake pedal and master cylinder in the other side of the firewall.
This is to the right of the last pic. You can still see the fuel pedal. The hump is in the exact center of the dash about seven inches below the windshield. The ting on the low right that looks like a heater box is the heater box.
This is looking strait up though the aformentioned hump at the wiper linage and shop ceiling above.
A longer shot of the area with my initial cut.

A similar shot with most of the cancer removed back to healthy tissue.

Holding the camera up into the cowel, looking behind the brake/stearing column support, you can see what is left of this issue at the time that I quit working this afternoon. I will tackle the rest in the morning.

I've owned this thing for over a year now. I even drove to Reno to pick it up. In the vid, you get a glimpse of me. Believe me, I am smiling on the inside. I've waited a long time to hear this. Like a Cummins, it did not hesitate to come alive.