A-Body Front Frame Rail - Anyone know what this bracket is for?

[KCBones]

I've got a 1968 Dart GT which has some underside rust issues. The main issue I need to deal with first is a rust hole in the front left frame rail right at the shock tower. There's a little bracket there, I've attached a picture and circled it in red. On my car, the hole is right behind this bracket and the bracket is pretty much gone, rusted away. Does anyone know what this bracket is for or what it does?

I was hoping to repair the hole and possibly replace the bracket if I can find one. I think I'd rather find a frame rail, or at least the front section of a frame rail that includes this area.

 

[tinman2]

Contact area for lower control arm bumpstop.

 

[KCBones]

Thanks, I guess that'll need to go back in. I may have to develop some fab skills if I can't find a frame rail.

 

[tinman2]

That's my plan too... to develop my fabrication skills. I enjoy learning new skills. I think when you can do things yourself, it's very rewarding. Lots of fabrication education can be found on youtube.

 

[dano]

Put up a wanted ad. Several guys here part cars.

 

[KCBones]

Put up a wanted ad. Several guys here part cars.

Thanks, I was thinking I would do that. I looked through the parts cars listed. Someone might have a front frame rail.

 

[ACME SS]

Fabrication of a patch to weld in would be the easiest in my mind and it is possible you could save that bracket. The concern I always have on frame material is the carbon content of it and with what filler metal and process it should be welded? I have tested the steel on a 51 frame with an alloy analyizer and it was ok to weld without any pre or post heat treatment and since then I found that frames up to the mid-80's are weldable, but always keep that in the back of your mind when working on structural steel. Higher carbon steel will go through phases as it cools and if you cool a weld too fast from the surrounding steel, it will not be normalized and will freeze in a brittle state. But like I said, that should not apply here from what I understand. Filler metal needs to be properly selected too so that you don't use something that would not be compatible because it can go both ways.

I usually will use a cut off wheel and cut out the thin area. Then I take the piece removed and use it, or paper as a pattern for the new piece. It depends on the thickness of the steel but on 3/16" I would probably want about 3/32" gap between the patch and the hole. You can tack something across the patch to allow you to hold it into the hole flush, like a handle. Then weld in the gap using small tacks. If your not a welder, this is the time to practice first. wire feed is the best in my opinion because it has the shortest learning curve but also puts less heat into the base metal. I know there are guys who love to tig weld everything and that is great and the welds look nicer in many cases but the amount of joules added to the base metal is sometimes a little concerning. Where you aim your wire is where the heat will go so I usually will aim at about 45 degrees into the gap to add to the previous weld, not directly into the gap.
Good luck

 

[KCBones]

Fabrication of a patch to weld in would be the easiest in my mind and it is possible you could save that bracket.

Thanks, I've had several friends tell me the same thing so I'm considering that as well. The bracket is gone and can't be saved but it doesn't look like a hard piece to fabricate. I was told it's the contact point for the LCA bumper so it'll need to be strong. In any event, this won't be a show car, just a fun driver. Thanks for your input, very helpful.
K.C.

 

[ACME SS]

Thanks, I've had several friends tell me the same thing so I'm considering that as well. The bracket is gone and can't be saved but it doesn't look like a hard piece to fabricate. I was told it's the contact point for the LCA bumper so it'll need to be strong. In any event, this won't be a show car, just a fun driver. Thanks for your input, very helpful.
K.C.

Sounds like you are on track! I used to work with a weld engineer who whenever possible would recommend bolting as opposed to welding. I found that to be a little odd at first but it all came down to the metallurgy and weld procedures. We had a 3" thick book of weld procedures and would write and approve new procedures every 4 months or so, as needed. This guy was the one who tested my frame material on my 51. The guy was in a panic when I told him I was doing a butt joint on the frame to replace the back 1/3 of the factory frame with my own rear frame. The fear became a little contagious and I complied. Good luck on your project!