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This part of the frame is on the passenger side between the bumper and the front tire.
I am going to cut out the bad part and weld in a new piece. 2 questions:
1. With what you see, would this be the proper fix?
2. If so, what and where would you get the metal from?
I want to make sure it is done correctly and will last and be safe. Once completed, I am going to treat the underbody, sand, use rust neutralizer and seal the underbody.
use good ole steel and match it to at least the thickness of the frame, if not a little thicker wont hurt anything. try to make the cut as square as you can so fitting the new metal will be smooth and easy to shape for the bend. just make sure to cut out all the rot and grind down the heavy rust to fresh metal.
Not sure what you mean by "seal" it but if you're referring to undercoating it I would not do that, it can crack and keep moisture inbetween the undercoating and metal causing an ideal situation for rust and rot to form and you wouldn't know until you stripped the undercoating off. what I did was grind down all the rust and then sprayed it with rustoleum black. I did this 2 years ago and it has held up very well, obviously a little dull now but I wasn't able to find any flaky paint the last time I was under the car. good luck
use good ole steel and match it to at least the thickness of the frame, if not a little thicker wont hurt anything. try to make the cut as square as you can so fitting the new metal will be smooth and easy to shape for the bend. just make sure to cut out all the rot and grind down the heavy rust to fresh metal.
Not sure what you mean by "seal" it but if you're referring to undercoating it I would not do that, it can crack and keep moisture inbetween the undercoating and metal causing an ideal situation for rust and rot to form and you wouldn't know until you stripped the undercoating off. what I did was grind down all the rust and then sprayed it with rustoleum black. I did this 2 years ago and it has held up very well, obviously a little dull now but I wasn't able to find any flaky paint the last time I was under the car. good luck
Thank you for the info Tyler. I thought the undercoating was the best way to go, glad I asked.
I am not going to do the welding, but I am going to do all the prep work.
you could cut that section off a junkyard car?
i get metal REAL cheap at scrap yards/recycling places. sometimes i find very interesting stuff, lol.
I went back and was looking at it all again and noticed that the bolt that you see in the picture is where the sway bar attaches to the frame. I need to do some research as to why I should do. I want to make sure it is fixed correctly and will be safe.
Cut out all the rust, at least 1/2" past the rust as well. Grind it all clean. Cut the new piece of metal, shape it and test fit it. use the hole in the sway bar link as a template and mark the hole, drill out 1-2 sizes bigger than the bolt and then tac weld a high quality nut on the back side of the replacement metal. Fit the new piece tac welding it in place at first and then 1-2" seam welds adjacent to each other letting it cool between every two welds until your have seam welded the entire thing. After all welded in clean it up with a grinder, if needed, then seal it up. tedious work but worth the work.
Thats what i would do anyway.
Last edited by Fanatic1074; Feb 29, 2016 at 09:26 AM.
I have that exact Peice of subframe cut out of a donor car sitting in my garage right now completely rust free, HOWEVER, it's the drivers side section.
Id suggest just going to a u-pull-it and cutting from a donor car. I've bought complete floors from donor cars for only 50$.
actaully, NO I would not use tig. The reason is, tig for a good weld needs to have a spotless weld area and it sure as hell will not do on rust (or even the zinc coating on the steel), a MIG is a much better choice here.
I recently had to do a similar repair for my floors and part of subframe. MIG is the way to go unless you can sandblast EVERYTHING. I personally used tig in a few spots where it was all clean metal, then the rest I did with arc (and frequently used a filler rod, like tig lol), its holding nicely. Only been a few months, but she's went airborne and held. Make real sure the car is straight and level on all corners before doing anything.
I would MIG weld it in place then just grind it flush and seal it when done. Tig would be nicer and wouldnt require griding but i prefer the MIG, Only time i use TIG is when i want to cleanup rolled welds or make it look nice, for a frame weld that no one is going to see, i would just roll with the MIG.
Mig or stick... No tig on that. Too dirty of metal.
Fanatic... You shouldn't have to grind a mig weld to make it look pretty. You should be able to lay down a bead that looks like stacked dimes with any good mig (not flux core) machine. Use a weaver pass. When I want real pretty mig welds, I move the gun in tiny tight clockwise circles with a drag pass.