Calling all bodywork experts -- where to cut core support to weld in new front end

[UnlimitedT4R]

A couple questions.

1) I'm away from the truck so I used Joelzy's photo. The passenger side "headlight" piece was undamaged. I'd like to try to not remove good material if possible, and removing that piece will require disassembling the A/C system because a pipe goes through it. So can't I just remove the spot welds circled in the photo below? That will take off the horizontal supports and leave the headlight piece on the truck which I know is good because it "lines up" (as well as a Certifit hood "lines up") with the new hood. I looked before and it looks pretty straightforward. The advantage of this is that it will be easy to line things up so they are in the right place.

2) Regarding the other end, you are suggesting that I overlap the sheets and weld that up. But on Arthur Tussik's channel I have seen him overlap the sheets and then run a grinder through both so that the cut is perfectly lined up. Then he welds that up so there is no seam. Can I do this, or is it not structurally strong? If I overlap then weld, I will have a raised line. Also, would I have to weld both lines of the overlap, one on each side?

As mentioned, I probably should have cut out the firewall too with the donor piece so I could take it all the way back to that. But on the other hand I think messing with the firewall would create some extra complications. The wheel bay isn't highly visible so I could get away with cutting a line and re-welding.

The metal is undamaged back at the firewall. Everything just folded up to the firewall. I test fit a driver's fender and it lines up well with the hood and front of the vehicle. The hood pillar is fine. The frame seems perfect except a bent lower control arm rear bracket which I'll deal with after I get the front end put back on and it's drivable.

I’m using my phone right now so I can’t tell from the photo what’s going on with the headlight “bucket” I’ll put eyes on mine in I few to get a better idea. As far as the drivers side upper rail/apron overlapping with plug welds would be the most structurally sound option. On areas you can’t overlap butt seams up and weld. Like you said, not much of that will be visible so focus on alignment and structural rigidity and you will be good to go. Give me some time to look over my runner to get a better idea of the details and I will get back with you.

 

[Mark_BC]

So upon further inspection it seems that the passenger "headlight piece" is also a little mangled from a previous fender bender. I think I should replace that too as suggested by others in previous posts. But this means I'll have to dismantle the a/c system since pipes go through that piece. I was hoping to avoid that. I'll watch all of [MENTION=120071]mtbtim[/MENTION]'s video later but first now, can anyone give me an idea of what I'm in for with this system? Obviously I cant drive it to a shop to be evacuated. It almost seems easier to just cut a slot in the new piece going in so I can slide the pipes through, then weld it back up afterwards.

 

[phattyduck]

You are going to want to have the AC system out of the way for painting anyway, right?

Either get a mobile AC guy to do it (do they exist?) or be a little illegal and release it yourself... It got 'damaged' in the accident and already released, *right*?

-Charlie

 

[Mark_BC]

No, there appears to be no damage to the ac system. There was little overall collateral damage from this collision, it is in way better shape than the original photos suggest.

I haven't run the ac but I have no reason to believe it's compromised. It is on the other side of the engine bay and the ac grill suffered only minor damage to some fins.

I'm ready to say, screw it, the damage to the headlight piece is so minimal and it would never be seen. So I could go back to the original plan of only replacing the horizontal supports.

I'll paint it before it goes in then do any touch up required after.

 

[Mark_BC]

Any suggestions on which caulking sealant to use?

 

[Johnny0]

drill out the center of the existing spot welds with an 1/8" bit, then get a unibit or step bit to drill out the rest of the sport welds, Should come apart easy with moderate force

 

[Mark_BC]

There is something strange going on with lining up the body and frame. It appears to be 1/2 to 1" off, side to side. See the photo below of the body mount not matching up. I took it to a frame shop last week to get it straightened since there was a buckle behind the lower control arm rear bracket. I'm wondering if that has something to do with it. The bushing was out for this procedure so there was no force on the body from the frame at the front.

When the bushing is out, the front part of the body seems to be 1/2" offset on the mount. To put the bushing in I really have to use a lot of force to lift up the body to get it in. Then it looks like the whole front part of the body (well, the passenger half of the front body that still remains) bends from the upwards force from the frame. You can see below how the headlight hole is not level, and the lower radiator mount that I cut in half, it angles up from the force. In this case it is out by 1".

(I'm having problems uploading photos to Flickr right now)

I put on the OEM hood from my other runner to see what was going on, since I know it is straight, and it seems to line up fine with it the way it is without pulling the body sideways to make it fit.

Could it be that the frame alignment place messed up the front of the frame? By that much? I'm not sure how to measure diagonals on the frame to check squareness since there is so much stuff that gets in the way to screw up the measurement.

Is there supposed to be a lot of upwards force on the body from the front mounts?

 

[Ifirefight]

If you need to use that much force, the frame is still bent. A good frame shop should have all the correct measurements in a book so they know what the factory specs were. My guess is that both frame rails are still bent...maybe one side more than the other. The best thing to do would be to take it back, or find another place and take the front clip with you so they can make sure it lines up. It’s not 100 percent necessary, but it would be best.
They should be able to get it right without the front end sheet metal on it. Remember, this needs to be square not only side to side, but up and down also..


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[Ifirefight]

Back in the day, we used something like this to measure frame squareness..I’m sure they have laser ones now, but this worked just fine 25 years ago.


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[Mark_BC]

If you need to use that much force, the frame is still bent. A good frame shop should have all the correct measurements in a book so they know what the factory specs were. My guess is that both frame rails are still bent...maybe one side more than the other. The best thing to do would be to take it back, or find another place and take the front clip with you so they can make sure it lines up. It’s not 100 percent necessary, but it would be best.
They should be able to get it right without the front end sheet metal on it. Remember, this needs to be square not only side to side, but up and down also..

Yeah after sleeping on it my plan is to take it back since the front body mounts lined up fine with the frame before he "fixed" it. I think he just didn't measure those front locations because they are in front of the suspension.

But I can't afford another tow there and back so I'm going to get it roadworthy first. I'll put on the front end so it is square with the rest of the body since I know that is good (doors and hood line up fine), and drive it over. It will be 1/2" off the front frame mounts but still driveable, I can put some support under it.

I was thinking it might be a bit presumptuous to weld on the front end before the frame is square but I know the body is good, and there is a little bit of adjustment available in the front mount holes.

I'll give him a call.

 

[Mark_BC]

I'm prepping the metal for welding next weekend. I'm removing the paint from the to-be-welded surfaces and applying Eastwood weld thru primer. Except where there were previous spot welds that I removed and it looks like there's already weld thru primer there, in this case I'm not removing paint, just touching up with primer. I assume that's what the grey paint is, weld thru primer?

My question is, do I need to remove the regular paint from the back side of the welded pieces? The metal there will get melted and I'm hoping that paint will just burn off the back side and not contaminate the weld. Removing all that paint would be a real PITA.

 

[Ifirefight]

Not sure I understand the question. But, the piece you are welding TO, needs to be clean grinded metal..if something is on the back side of that part (like paint) it’s not a problem. The (new) piece you are welding to the part I just mentioned, should be grinded on both sides of the metal. You should basically have holes drilled in the new piece, grind it on both sides, then grind the small area that the weld will contact on the (old) part. Then weld together.


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[Mark_BC]

Not sure I understand the question. But, the piece you are welding TO, needs to be clean grinded metal..if something is on the back side of that part (like paint) it’s not a problem. The (new) piece you are welding to the part I just mentioned, should be grinded on both sides of the metal. You should basically have holes drilled in the new piece, grind it on both sides, then grind the small area that the weld will contact on the (old) part. Then weld together.

Yes, that answers the question about the paint on the back side of the piece being welded TO. But the piece that I will be welding, I am coating it with weld-thru primer because you could never get paint around and inside the new welds after they are spot welded on. So weld-thru primer is designed to be put directly on the clean metal before welding and then it leaves behind a protective layer after the organics get burned off in welding. I am assuming that the grey paint I can see in the spot welds and other hidden areas is weld-thru primer from the factory, so I'm not removing that.

 

[Ifirefight]

The “grey paint “ is most likely weld thru primer. You should be fine leaving that...however, I would do a test weld on the grey paint area to see how it goes. Back in the day the weld thru primers did not work very well, they tended to interfere with the weld. Maybe they have improved them in 25 years..


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[Slayer406]

no idea on the back of the inner fenders but these might help a little on the spot welds.

[

this was once i had the factory core support off and shows where the spot welds are

I used every C clamp and vise grip i own to hold it in place where i wanted when tacking

being that the new support was solid and i had holes in most of the inside weld spots, i plug welded it from the back with a mig welder

Doesn't look like anyone has been following this thread for a bit, but I figured I'd tack on here rather than post a new discussion which has probably been started a thousand times. I found this post to be super helpful and I was just wondering if anyone had any leads on replacing the mounts the radiator support sits on. I'm having a lot of trouble tracking these down and the dealership wants way too much. I bought a 98 Limited that had a wrecked front end because it was only $1700 and everything works, including e-locker. Plus it has about $1700 worth of tires on it. I've got all brand new pieces to fix but these bushings are holding me up on pulling the trigger. If anyone sees this and can provide some guidance I'd really appreciate it.
Also, I'm not super tech savvy so I didn't want to mess with the text of the original message.

 

[2-Skinny]

Doesn't look like anyone has been following this thread for a bit, but I figured I'd tack on here rather than post a new discussion which has probably been started a thousand times. I found this post to be super helpful and I was just wondering if anyone had any leads on replacing the mounts the radiator support sits on. I'm having a lot of trouble tracking these down and the dealership wants way too much. I bought a 98 Limited that had a wrecked front end because it was only $1700 and everything works, including e-locker. Plus it has about $1700 worth of tires on it. I've got all brand new pieces to fix but these bushings are holding me up on pulling the trigger. If anyone sees this and can provide some guidance I'd really appreciate it.
Also, I'm not super tech savvy so I didn't want to mess with the text of the original message.

Do you mean the steel "sleeves" on either side of the radiator with hooks to hand from the core support and threaded holes to bolt to?