tub removal bracing jig

[scruffy1]

This summer I'm looking at removing my tub to replace the floor, clean up and paint the frame. I've heard of the need to build a bracing jig to keep the body square when doing the body work. I've searched and cannot find any pics or directions on how to build one. I would like to use 2 x 4's for the jig since I'm more of a carpenter than a welder. Where do I look or what search terms should I use? I found a post where FELIX talked of a jig he built but could track it down.

[Cuz]

You don't have to weld to have a decent metal forming frame. I try not to use the word jig when I'm not really jigging anything. Steel is a lot better for this stuff than wood.

Before you remove the tub align the tailgate opening so you have a straight equal gap on each side. You can jack the tub open or use a ratchet strap to pull it closer. Then take a piece of steel strap 1/8" by 1" or 1" steel conduit and cut it about 4" longer than the opening for the gate. Now bend about 2" over at each end so it fits tight between the two chain brackets at each side of the tailgate opening, drill a 5/16" hole in the bent ends and bolt them to the brackets.

Use the same material to make a pair of diagonal braces from each side of the dash (pick any convenient hole) up high to the opposite rear corner of the tub. And finally place one straight across the center of the tub (you can use a pair of footman loop holes on the top edge of the tub on each side).

It is also easier to then mount the tub in a rotisserie. The rotisserie can even play as part of the former system. Below is how Ryan Miller did his:

[Felix]

The picture posted by Wes of Ryan Miller set up is the dream of every jeep restorer; unfortunately I did not have the room or the funding to go after something like that.
The fixture that I built was intended to keep the tab from twisting when the floor was removed. The floor in my first M38 was practically gone and when you start cutting the reinforcements it could twist and also sag.
I build the fixture using 4 x 4 redwood. Wood is very good for making fixtures because the method of fabricating (bolting) is much easier than welding, besides the fixture that you are welding can also warp due to the heat of the weld.
Essentially I had (1) 4 x4 running along the edges of the tub connected with (3) short 4 x 4 running across. The joint between 4 x 4 were done with metal bracing used in construction. I tag welded pieces on the edges of the tub (4 per side) and bolted the pieces to the frame. This would prevent the tub from sagging and twisting. The next thing is to keep the relationship of the holes in the floor to the sides and to the firewall, or to the rear door. For this I used a tell angle 1 ½ x 1 ½ tag welded the edges of the tub and drill holes through the steel angle in line with the tub mounting holes and in front of the driver and passenger seats I screw the front steel angle to the tapped holes in the transmission hump.
Then I proceeded to remove one panel at the time and put the new one in place and spot weld. I almost forgot, I also located the hat channel that under the tub using the jig. The more points you fix to the jig the better assuming they are not in your way for cutting and welding.
Good Luck

[Jeeps4Brains]

You don’t have go the dream bracing route. You just need to weld on some pieces to keep the body from shifting when you start removing body panels.

In my picture you can see I just welded some leftover pieces of metal to the body to make it more rigid.

I welded my pieces on top because I wanted to be able to work on the bottom without anything getting in the way. You can’t see it in the picture but I welded a piece across the bottom of the rear floor too.

Take measurements from the mounting holes to the cross members and record it making a sort of diagram, then refer to it when you add the new floors.

I would not cut all the floors out at once. Remove them and replace things in phases and measure after each piece. My two cents.

Alan

[Felix]

The picture submitted by Alan shows bracing that will keep the sides parallel to each other and the firewall/dash spaced properly from the rest of the body. He indicates that there were cross members across the bottom and that is good but there are not showing in the picture so I can not asses if they can take care of one important thing; the “potato chip effect”. None of the connections shown in the picture will prevent the tub from taken the “potato chip” shape. To prevent the potato ship shape the four corners of the tub need to be connected by a rigid structure. The “potato chip shape” is not easy to detect until you mount the tub on the frame, at that point you may discover that holes in the floor may (may not line up) but they might be displaced vertically making the connection with the clamp down screws challenging, to say the least. In the M38 this is critical because if the tub moves in the potato chip mode the starter pedal that mounts to the floor may not line up with the lever on top of the starter motor. By the way, that last, is experience talking about something that quite an amount of work and compromise to fix.

[scruffy1]

Thanks for the various ways to get this done! I'll use all the information to create rigid and square bracing keeping in mind the "potato chip" effect
This forum is great!

Mike

[Prairie Boy]

I would be looking for pictures or illustrations if possible. I am not sure I like the idea of welding to the body, but if that is the best way, then I would like to hear it.

I have to redo all the floors for my M38, so I would be looking for something along the top to allow work on the bottom. the one Wes described sounds good, but I am not sure how one would brace diagonally to the tub?

Thanks in advance.