rear frame fabrication

[MrQuick]

Hi guys im working on a 67' ChevII and im doing a custom 3 link on it. Im replacing the frame rails and adding a cross member to mount the links to. Now I have the x member and the frame rails tacked in. I was looking at the whole deal and it looks like I can drop the whole pig out. My question is: now that I have the rear rails and x member tacked and measured out for the car, can I remove the whole unit and complete it out of the car? Or should I just weld it up in the car? Some of the parts I need to get to and weld are very hard to reach, this would make it alot easier as you can imagin. Request assistance please

[zbugger]

I'd think that you could remove the entire thing as a unit, finish weld it, and then reinstall it. But I'd also worry about heating the metal and warping it a little. Maybe make a jig to keep it straight?

[Matt@RFR]

Vince, all you'd be welding is the crossmember and upper link mount, right? How are you attaching the frame rails to the car? Do you have a flat welding table to clamp the frame rails to?

What I would recommend is to weld as much as you can while it's in the car, and still be somewhat comfortable. Then, after it's cooled to room temperature, take it out and clamp the frame rails to something thick and flat. (You can shim up to flat if you don't have anything nice and flat to begin with.) Then tack or clamp some temporary braces between the frame rails, and make sure they fit ultra tight. Make sure it's tacked up really well, and weld. Try to skip around as your welding so no one joint gets too hot.

Let it cool to room temp again before cutting out any bracing. Just remember that the filler metal will shrink as it cools, causing it to pull the welded pieces in that direction. Picture how all the welds will try to pull everything and try to brace against that.

We can talk more about bracing if you want to post pictures of the assembly out of the car.

[MrQuick]

Hey guys, the frame rails connect to the x member also.The plans are to weld the x member to the car and then making a set of subframe connecters to tie into it.That will go in after the rear is done. The 10 point roll cage will tie it all together.
The x member is just tacked on to the exsisting car frame which is cut short,and the rears are supported by a temporary support bar.I will weld in a 2 x 2 to support the rear frame to the body. I will most likely build a jig frame for it then weld it out of car. Just to make sure this thing holds together. Thanks i'll get more pictures when its out of the car.

[F70t/a]

Damn vince that look's good!! I will be coming to cali in a month or so. maybe I can stop by and check it out. I will let ya know. take it easy

[F70t/a]

Hey vince, what areas of the trunk did you brace?

[MrQuick]

Hi D, I braced the rear section of frame that is left, side to side then from there to the trunk filler the to the furthest most rear section of the quarter panel to rear panel. The body is also supported at 6 spots.Made sure it was level and square before I did any cutting.

[F70t/a]

Looks good vince