Rear subframe rail rust, mouse nests

[jtschug]

Are you working with ordinary cold rolled steel? Or is this something fancier?

It looks like it has some work hardening which caused that fracture. You may need to heat it up so you don’t cold work it as much, at least cherry red. Most easily achieved with oxy-acetylene

[Rt.146]

You are doing some difficult work, which luckily for my car I did not have to do,welding and fabricating are not a high point for me. I know you will want to keep your trunk as water tight as possible, so I will bring up where the studs for the rear grill go behind the rear window, those studs go through rubber grommets then the grill is fasten from the inside of the trunk to the body, the grommets after 57 years will deteriorate allowing water to drip into the trunk, sort of a "phantom leak" looking at these grommets casually, they will appear to be fine, though a closer inspection they will show their age. You may want to examine yours before closing it up.

[David Langhorne]

As per jtschug I am puzzled as to why the metal is cracking. I have used 16ga for at least 30 years in an amateur way on my own cars and I have found it very difficult to bend it back and forth enough to break it even when trying. I always use 16ga when the repair is not visible as it's easier to weld and will also last longer. I have only used 20ga where it is necessary to shape the piece more such as door bottoms and rear quarters.

[Dunk67]

Cold rolled steel, a small piece from Lowes. Grabbed it while I was there because I only need a small amount and the metal supply house closes early on weekdays and is not open weekends. Turns out it's a defect, it must not have been annealed. If I heat a small piece red hot for a bit and allow it to cool to ambient it will bend fine with no cracks. I'll get some 16ga from elsewhere or try to get to the metal supply house Friday. I'm using 20ga from the metal supply place and have had no issues bending or welding that for the wheelhouse and trunk floor patches.

Regarding the rear window trim studs. Yes these grommets looked rough and were coated in some sort of black tarlike sealer. Not sure if it was factory or someone trying to stop a leak. I'll have to figure out what to replace them with when it goes back together. Fortunately I'm a long way off from that so I've got time to figure it out.

[Dunk67]

Not much done this week, busy work week and a 16 hour day today. Found a little time to putz around the garage while applying more Rustoleum gel. It's slow but works a treat, faster than Ospho. Maybe higher acid content or maybe because the gel stays in place better. I leave it on for an hour or two and spread it every 30-60 mins with a nylon bristle brush to keep all areas wet and agitate any loose rust. Rinse it off with the hose after it starts drying up, then blow dry with air. About 5 or 6 application in, with a few Ospho applications inbetween but the Rustoleum gel works better. Almost down to clean metal in the soon to be inaccessible areas.

I did pick up some more 16 gauge cold rolled. Cut a piece for the frame section I cut out using my template from the weekend... And forgot to add 3/4 inch for the lower flange. Oops, I was going to add a note on my template but figured I could remember it for 15 mins... Didn't anticipate making another part a few days later. Oh well, did a couple test bends and it bends much easier with no signs of cracking.

[Dunk67]

The subframe rail has a sharper bend from vertical to horizontal, then a radiused bend from horizontal back downward to vertical. I decided to try to match the radius bend. I got a Grizzly 4" vise brake (https://www.grizzly.com/products/grizzl ... rake/h3243). Easy to use, makes nice bends. Probably not too hard on the vise with thin material. I think I will re-grease the screw on mine before doing any more 16ga though. In any event it makes a very sharp bend like a regular brake would. The fingers come to a point, and are mounted with 4 allen screws to clamp them in place. There are 1/4" material.

I found 5/16" round seemed about right to match the bend so I cut a 4" length of that, ground it flat on one side, and welded it to a 4" long piece of 1/4" flat bar. Since the 5/16" round was thicker than the 1/4" bar stock I used a magnet on each side shimmed with a razor blade, to roughly center the round bar but more importantly ensure it was level side to side. Welded up and replaced the pointy jaw from Grizzly with my contraption. A quick test bend and the radius was about dead on with the factory subframe radius. It worked a treat to bend the real piece though I had to bend a bit at a time and shift it side to size since my patch was about 5" long.

I then made the patch, and welded it in. Not thrilled with my welds on 16 gauge. I'm less consistent than I am with thinner material. It's a fine balance between not enough penetration and burning through. I got very consistent in my practice, but I was practicing in a normal orientation. Working upside down and around the leaf spring threw me off. I should have practiced upside down and removed the leaf spring. I'll do that for the other side. Oh well, I think it's serviceable, and goes with the theme of this project of it's better than it was.

[jtschug]

Nice work!

[Dunk67]

The inner subframe rail was quite crusty and this behind the tie down brace. I cut that out yesterday along with a replacement piece. I was not feeling it for figuring where to make the bends and fitting it to weld in tonight so avoided that. I pulled the tail lights out and was hoping to get access to the crusty bits at the back of the trunk, but the panel forward of the tail light assembly requires the bumper be pulled to remove it. I don't want to remove the bumper until at least one side of the rear subframe is patched up, to keep the car as rigid as possible. Also ground some spot welds and did some other mindless cleanup work along with servicing some of my tools.

I'll likely patch the passenger inner subframe rail, remove the bumper and inner panel, patch the passenger rear trunk piece, reinstall the bumper, then weld in the new inner and outer passenger trunk panels, and move move on to disassembling and patching the driver side subframe and trunk.

None of this is rocket surgery, but it's tedious. Gotta be in the right mindset for the precise bits though, or I might end up just making more work.

[Dunk67]

I got an extended reach die grinder which was super helpful using a 1" wire brush to clean the rest of the rust in the bottom of the frame rail, couldn't reach that far with my regular die grinders.

Measured and made by bends in the frame patch for the inner side. Then trimmed to fit. I have to say the 3m Cubitron discs are worth every penny. So much better than flap discs for grinding welds and fitting patches for butt welds. Cut faster and last longer.

Since I had access I welded the cold sections of the outer frame rail patch from the inside. I cheated by clamping a copper spoon to the outside of the frame rail. Looks much better now so far as penetration. I still suck at welding.

Not really sure what I'm doing with any of this, so just winging it. My method is cut out the rusty/thin piece. Then make a paper template and hold it against the good metal, by hand or with magnets, mark with a sharpie, cut it out, mark on metal with sharpie and scribe as needed for my size and approximate location of bends. I cut a tick larger than needed. i then mock up the metal piece and mark for bends, bend it, trim to approximate size and fit as best I can, then hold it against the place it needs to go and use a sharpie to mark for a guide. I found some "Sharpie Mini" that worked great for the limited space inside the subframe rail.

Now that my patch is fitted to the car I need to cut a hole to match the tie down brace.I'll probably mark it using the brace, drill a hole in the center and use a carbide burr to size the tie down hole. Drill two holes for plug welds down low on the new piece before welding it in, then the three holes for plug welds at the top I'll drill through my welds after it's in and plug weld to both new and old metal to try to tie it together better. I'll smooth out the rust pits better before putting it back in, and do weld through primer.

While under the car I poked around some more at the driver side frame rail. It's much worse, kind of intimidating. I'll do my best when I get to that side. I'll have plenty of practice on all the passenger side bits at least.

[Dunk67]

Passenger rear subframe rail is patched up. I trimmed the new piece to match the length of the existing inner subframe rails including the 90* bend at the bottom, which I had bent straight down to size it. Then bent the 90* in my patch, bent the original parts back how they were, and welded in the new panel. A few holes and plug welds and it should be good.

Next steps for the frame rail is likely Eastwood inner frame coating up to the wheel arch with their extension nozzle, and Eastwood rust encapsulator inside the frame rail. Then I can put the patch for the inner part of the trunk floor back on over the forward part of the frame rail.

I removed the bumper, a real pain with the outer 4 cage nuts behind the tail lights spinning. When these go back I'll use plenty of anti seize and maybe reinforce the cages a bit. PB Blaster, and jamming some screwdrivers between the cage and nuts worked for these. One screwdriver I heater and bent at about 90* for access.

Plenty of horror and sins hidden underneath. More to patch but better access now. I'm thinking the rear trunk panel is next, I will likely remove it to patch the lower part the trunk floor over the frame rail attaches to. There is a brace on the side of this panel that goes back to where the quarter panel attached at the bumper that needs some patching. The top part under the trunk lid is all bondo. PO was a real bondo artist, which surely accelerated rust. Not looking forward to fixing the trunk seal area.

Not sure if anyone is following this or has any interest. I guess it helps keep me accountable and motivated to post progress though.

[Terry64HT]

I am following every post and am amazed at the work you are doing. On my 64 the trunk was good when I bought it, but the lid seal was in poor shape. I foolishly did other things for a couple of years first and when I got to the trunk, water had leaked in enough to rust out the floor. Fortunately, Classic had all the pieces I needed and I was happy to pay a local body shop to do the work (I'm not a welder guy).
I'm pretty sure the cage nuts are readily available, just be careful of the thread. I also know that Classic Sheet Metal has a replacement trunk seal channel should you choose to go that route.
I'm cheering for you
Terry
64HT

[Dunk67]

A bit more progress, mostly disassembly and figuring what needs holes plugged.It took much longer than I thought to get the trunk rear panel and quarter panel rear brace out, at least to keep them intact for template and patching purposes.

Overwhelmed by the horrors I found I moved on to something easy, patching this hole.

I roughed out a patch. Need a some more bend and trimming but it's mostly there.

I ran out of steam at that point. After all the disassembly I wasn't feeling it to make patches. For extra fun there was rot behind the flange and spot welds so I'll have to patch that too, but it should be a super simple piece. The patch drops in pretty nicely and I'll finish it up next time.

This is a lot of work on an old bird for someone who is not a Thunderbird guy. At the least I guess I can save one cool old car from being scrapped. I'll save the horrors for later. Either way, one month in and at least it's better than it was.

[Dunk67]

I finished up that rear panel section. Three patches required.

I am probably getting near a point where I need to start covering the bits I've done with something, to avoid surface rust popping up in the humid wet east coast. For some bits I'm totally done with like the frame rail I will use the Eastwood rust encapsulator. For some of these other bits I'm patching I'm not sure I want to use it as it's supposedly pretty hard. I'm considering red oxide primer as the factory used. An epoxy primer would be best for each section as I get done with each area, but I'm not too keep on isocyanates, certainly without either getting a fresh air setup or at least a big vent fan out the back wall of my garage.

In any event a bit of disassembly, cleanup, and straightening on these bits before I start patching them. The flat piece at the rear of the trunk should be pretty easy to patch. Super easy at the bottom, a bit more work at the top given two bends, three counting the tab to shield the panel from the drain hole behind the trunk seal but I may just weld a small piece of scrap on for that. The quarter panel rear brace will be a pain, not sure how I'm going to do it given the complex curves and my limited skill.

The inner quarter extension also needs work. I have a replacement panel from Classic Sheetmetal but it does not have any drain or access holes nor any bend at the rear, it's just straight back. I should be able to use the rear curved part of the existing panel where it bends to be spot welded to the lower quarter panel and the rear valence, and I can drill that rear hole easily enough. There is no provision for the drain at the front, I may have to get creative for something good enough or better than no drain.

[dgalietti]

I love this stuff. I can't wait to see more.

I see zero reason why a T-bird is less worthy of this kind of work than any other classic car.

99.99% of classic cars would need some kind of sheetmetal replacement/ rust repair like this if you really looked close. Every classic car it seems had it's problem areas... Trunks, rocker panels, drain channels, cowl areas, etc.

[Dunk67]

I've been on an extended spring break from the '66 Tbird. Tentatively have a deal to get the back 4'-5' or so off a '66 to get some better metal to replace the crusty bits on this one. Dude is taking his time to get his garage and vehicles in order before the Tbird he's parting out becomes much less mobile, which is fine by me as I've been working on a backlog of other projects.

I got my XL600 back together, now a 80mm XR600 crank with a 101mm overbore XL600 cylinder for 641cc. Ported the head to early big port size for the 2mm larger early carbs I picked up. Ran great but burned more oil than my two stroke so it was time for a freshening up and improvements. Super fun.

I also started work on my XL350, valves failed and leaked badly losing compression. Top end rebuild, adding XL250 oil cooler,\. Unobtainium pistons and such for this but got NOS rings since the bore isn't horrific and already .5mm oversize. I'll cut the seats, lap it in, and do the other bits and toss it back together. Should be good.

Carlisle Ford show was this past weekend. Big rush for that getting the the old man's relatively new to him Tbird serviceable but it didn't work out. He has some mobility issues and brakes were not serviceable for him to use for the drive. Looking for a bigger bore master and maybe more power assist to make it easier for him.

Also my buddy that recently moved back to FL flew in and we had to get his '61 serviceable to go to Carlisle and then down to his new home in FL. Despite tires old enough to drink and various neglected bits he made it home today.

I also had to get my better half's daily driver Bronco II ready for the show. That was the easiest recent endeavor, but still took a token effort. We had a good time driving it there as support vehicle and such. Seems the slushbox overdrive gear in the E4LD or whatever it is, is now failing. No big deal, we have a 4.0 and M5OD from a '94 Ranger to rebuild and install. Should be a good upgrade for her. We got the hang out with the other II's while we were there, the riff-raff vehicles gotta stick together.

Looking forward t0o getting back into the '66 Tbird. Gotta finish up the XL350, install an aftercooler on my compressor since I think I'll be painting this one myself, and various other bits. We'll get there.