Frame repair advice (updated with progress) (1 Viewer)

[hooter]

1970 FST us spec FJ40
On the inside c channel, in the area circled in red, I have bubbling, flaking rust.

I have a 2 short sections of spare internal c-channel. Not enough to repair the entirety of the internal framing.

Should I unbox the frame and replace the whole channel? Or is acceptable to only replace the rusted out section portion of the inside bottom of the internal C?
Kinda hard to explain what I’m thinking.....

a better question, How would you repair?

Hooter

 

[hooter]

Pics are better.


Here’s the rot. (Frame is upside down

Can I just patch this area or should I unbox the whole side of the frame and replace it all?

 

[47coeman]

You can do it either way, I would approach it trying to do the least amount of welding in replacing the metsl. Also making sure you are into good unrusted Metal. I believe you have the right idea going into this part of your project.

 

[FJ404345]

Another frame maybe ?

 

[FixedIt]

I have a 1970 FST too! Mines 6/70

 

[hooter]

Another frame maybe ?

That would be nice. It’s only the inner channel. I’m a glutton I guess.

 

[hooter]

I have a 1970 FST too! Mines 6/70

Want to donate the frame to me!!?

 

[FixedIt]

Oh man. I just got mine looking pretty. I can’t spare an inch of metal! I’m sure there’s an awesome vendor who would sell you a length of the frame you’d need.

 

[hooter]

Oh yes just pulling your chain.

 

[DougAustinTx]

I have welded on cars and trucks for 50 years, oxy/acet, stick, tig and mig. That frame doesn't look like it needs that much repair. Just use the piece you cut out as a pattern, go to your local metal supply and get some new metal of the correct thickness and weld it in. You don't HAVE to perforate it like the original. The perforated metal on the inside of the frame is to add stiffness. Just fix that spot and be done with it. Wire brush the loose rust, apply OSPHO to all the rusty spots, then paint with POR-15 or a similar coating.

 

[65swb45]

I have welded on cars and trucks for 50 years, oxy/acet, stick, tig and mig. That frame doesn't look like it needs that much repair. Just use the piece you cut out as a pattern, go to your local metal supply and get some new metal of the correct thickness and weld it in. You don't HAVE to perforate it like the original. The perforated metal on the inside of the frame is to add stiffness. Just fix that spot and be done with it. Wire brush the loose rust, apply OSPHO to all the rusty spots, then paint with POR-15 or a similar coating.

Agreed. I wouldn’t go through all that trouble just to weld in a section of ANOTHER 50 YEAR OLD FRAME that was made out of recycled steel to begin with.

 

[middlecalf]

The holes in the inner box are necessary for access in the bucking of the rivets, not to add stiffness. The inner box is for flange support (lateral instability) of the outside load-carrying frame. By design the frame will have some flex, Toyota’s approach to eliminating cracks in overstressed frames. You’ll have to decide if your going to bolt or rivet whatever replacement you put in. Either will function, decision will be on how much originality you require/desire.

 

[hooter]

Thanks for the replies.
I'm leaning toward originality which means I'll likely do things a really difficult way, unnecessarily! I removed the front cross member yesterday. It should be a fun(d) adventure going forward.

hOOter

 

[hooter]

Work continues.

frame channel replaced and rotten metal removed from bottom lip.

Grafted in a replacement piece of metal for the internal channel.

Welded to internal frame and holes drilled for rivets.

Next it’s off to blasting followed by primer/por-15 followed by solid hot rivets replacement and then final paint.

Hooter

 

[hooter]

Welding begins.

Torch and bucking tool/air hammer

rivet head

one side done

Close up

hOOter

 

[hooter]

Torching/bucking

completed and reprimed

Finished replacement of one inside channel and front cross member.

Maybe it wasn’t worth doing but I’m glad it’s done the way it is. I think it’s close to ‘factory spec’ and I’m happy with the rivet process. No more rust, fully blasted and primed. Next a bit of filler when there’s some pitting, then paint.

Hooter

 

[mattcamp]

Torching/bucking
View attachment 2306784

completed and reprimed
View attachment 2306785
Finished replacement of one inside channel and front cross member.View attachment 2306783

Maybe it wasn’t worth doing but I’m glad it’s done the way it is. I think it’s close to ‘factory spec’ and I’m happy with the rivet process. No more rust, fully blasted and primed. Next a bit of filler when there’s some pitting, then paint.

Hooter

You're making me feel like a hack!

 

[69LC]

Nicely done sir!

 

[syds fj 40]

beautifully done!

 

[cruisedeisel]

Sick job!