Welding in new box frame

[GeoW5]

So I am going to replace a section of the front cross Member that also holds the steering gear box as someone hacked out a section to fit in a Saginaw gear box. I am going to grind out the rivets and replace the section with a used piece. What does anyone recommend using to replace the rivets? I plan to put a mini truck steering system in.

 

[Grayscale]

Don't do it. Repair it, so you don't loose the frame, as getting it square isn't something that is going to be easy to fix. Replacement body panels, sure, but not the frame. Typically, just burn-in some plate over the sloppy hole (probably an oxy-torch is my guess).

You'll need frame rivets if you decide to risk it, as bolts are always going to be bolts. You'll find threads where people use something like a button-head screw, for looks, but then they weld the already heat-treated fastener to keep the nut on, go figure?

 

[SteveH]

So I am going to replace a section of the front cross Member that also holds the steering gear box as someone hacked out a section to fit in a Saginaw gear box.

I agree with Grayscale - don't cut out that whole crossmember. No matter how bad it is, repair it. Bolts do not (and cannot) replace rivets as they do not expand in the holes and lock the metal together the way hot rivets do. You can properly fit replacement metal in the hacked out areas, then grind/paint and it will look and work well. Post pictures here if you think we're all nuts.

 

[JohnnyC]

Builds - 1974 Reassembly

Greetings. I purchased a 1974 FJ40 as a project for my oldest son and I to work on. The truck is red and virtually rust free. The truck had a V8 conversion where the front motor mounts were removed and a Saginaw PS conversion. Whomever did the conversion did a pretty crude job that included...

forum.ih8mud.com

 

[GeoW5]

Great suggestions guys. Here is a pic of what I am dealing with.

 

[Malleus]

...or you can just use rivets. They're not extinct.

 

[Grayscale]

That is worse than I thought. I do see evidence of molten iron. I couldn't imagine that the frame is square now, with all that work done to it. They took the corners, and that was probably very important for maintaining the space.

Do you have something to heat rivets with?

 

[GeoW5]

I do not have any idea of where to get rivets, what size as I am sure they are metric and don’t know how to heat and install.

 

[Grayscale]

SOR advertises/sells them. I don't know how you would install them, unless you do it (the rivets themselves) upside down. Place a jack-screw in the frame, with a depression for the rivet head, and expand between the ears of the frame. Then quickly heat the rivet, and wack it with a die shaped to how the rivet should be when cool.

 

[GeoW5]

yes heating the rivets and some how installing them is going to be the trick… maybe SOR know how.

Also i see you mentioned a cutting torch, has anyone tried using plasma cutter for a finer cut or a large cutting wheel on a grinder? I also have to move the rear cross member to accomodate a 5 speed transmission in addition to the front cross member work.

 

[JohnnyC]

Did you go to my post above? It has sizes …. And… how to

 

[Grayscale]

On the other hand, that front bumper pretty much replaces your front cross member if it was welded top and the bottom frame ears, as far as function and maintaining geometry. But, with the middle cross-member relocation, I'm personally out. I can tell you how I'd run away from trouble, not how to run into it. Maybe limiting one-frame modification per rebuild, but, doing two, I don't know... Lots of variables. I know that professionals do this kind of thing, and I respect their skills.

 

[GeoW5]

I just now finished read it all. Was that you? anyhow next step is to watch that video.

 

[brian]

lol.... warning-not for private use

 

[pb4ugo]

The PO hacked in a sag box on one of my 40's and had to deal with the same thing. I tried patching it a few times. Eventually I replaced the whole crossmember and went to scout steering. That portion of the frame is a high flex area. Even removing the box and patching the crossmember probably won't work. About 20yrs ago, i used fine thread grade 8's and tacked the nuts to the bolts. Today I'd probably use rivets. When I moved my shock tower I used button head socket cap screws. They sort of look like rivets. You might put a wanted ad in the classified section for a good crossmember. There is a guy selling a new one in there too, but it's pricey. Replacing the crossmember wasnt that difficult. Remove the bumper and rivets then use a jack to spread the frame rails apart. It might be easier to adapt an fj60 or fj80 box. Reinstalling the center arm and stk steering links seems like a step backwards.

 

[GeoW5]

Great points pb4ugo. I have a front cross member piece but I should get a new one. You have the link handy for the person selling a whole one?

 

[GeoW5]

here is my replacement frame section that i purchased.

 

[pb4ugo]

For Sale - FJ40 Cross Member

Description : CROSSMEMBER SUB-ASSY, FRAME, NO.1 P/N: 51201-60014 Condition: Stock item in good condition with very tiny rusts Fitment: FJ40, FJ43 & FJ45 from 81’-84’ Price: $300.00 Weight Approximately 10KG Shipping: Express EMS door to door $127.73 within 15 days maximum

forum.ih8mud.com

I'd probably use the one you have if its not cut up or not structuraly compromised. Just remove the rivets and clean it up and install it.

 

[GeoW5]

I think so as well. Any thoughts on a plasma cutter or cutting torch if one is better than the other for this type of work?

 

[pb4ugo]

I just noticed it's for a later model frame.