Chassis Repair Progress

[packrat79]

I'm almost afraid to get a professional opinion on this "work" I'm doing, either for fear someone will tell me it's unsafe, or they'll just think I'm an idiot for even trying. But this repair is so unusual, especially for an old Honda Civic, that I just had to show someone what I've done so far.
You may remember a previous post where I showed this picture:
http://i282.photobucket.com/albums/k...flangebolt.jpg
This shows the area where the right trailing arm bolts to the body. The area to the right of the arm was so badly rusted, that it literally started coming off when I tried to turn the bolt at the bottom. I initially figured this was a dead end, but after some serious brainstorming I managed to come up with a course of action. The idea was to rebuild the entire area, using a double-folded piece of sheet metal as a start and then reinforcing the heck of out it, using pieces of 1/8" iron bed rail. It's a bit hard to explain, so I've drawn this (partial) illustration:
http://i282.photobucket.com/albums/k...lustration.jpg
And here's what the actual repair looks like so far:
http://i282.photobucket.com/albums/k...amerepair1.jpg
http://i282.photobucket.com/albums/k...amerepair2.jpg
http://i282.photobucket.com/albums/k...amerepair3.jpg
And a view from above, where a temporary hole had to be cut to allow access:
http://i282.photobucket.com/albums/k...amerepair4.jpg
Note that virtually everything, including most bolts, has been welded in place. The original bushing flange was used a reference, which should prevent any deviation in camber or toe worth worrying about. The final step will be to enclose this in sheet metal to prevent corrosion, as well as adding rustproofing holes where necessary.
That's about as good as I can describe it. Despite the homemade appearance, I can assure you it's a very solid repair and it will be even more so once the wheel arch and outer body have been rebuilt around it.
Your opinions are welcome, but please go easy on the criticism (not that it matters anyway).

[Epistemology]

I don't know a lot about the specifics, but you might not want to just jump into this project without some understanding of vector analysis.

You need to know how much force is going to be exerted on the area, then you need your "bandaid" to be able to withstand that force (and the angle of the force, et cetera). A scientific calculator with functions like tan will make this easier. You'll need to figure the weight of the vehicle (technically, the force of gravity and momentum), force applied by positive and negative acceleration, etc.

You could just "wing" it, but for a job of this scope, I think it would be fun to fix your car and learn something about applied physics in the process.

Less abstract: Aren't Honda Civics unibody vehicles? Unibody vehicles are a lot more sensitive to rust problems and bad repairs (making knowledge of forces applied much more important).

It might be fun to put the Civic on a frame (making it body on frame-like).

[packrat79]

Originally Posted by Epistemology

You need to know how much force is going to be exerted on the area, then you need your "bandaid" to be able to withstand that force (and the angle of the force, et cetera). A scientific calculator with functions like tan will make this easier. You'll need to figure the weight of the vehicle (technically, the force of gravity and momentum), force applied by positive and negative acceleration, etc.

.

I considered every possible force this area would have to take, and designed the repair accordingly. The mounted bushing prevents side-to-side motion, so I concentrated mainly on up/down and forward/backward forces. The L-shaped steel (or iron, not sure) is much heavier than the factory metal, and should be able to withstand some serious punishment.
Yes these unibody chassis' are certainly not easy to repair.

[packrat79]

Originally Posted by Epistemology

You need to know how much force is going to be exerted on the area, then you need your "bandaid" to be able to withstand that force (and the angle of the force, et cetera). A scientific calculator with functions like tan will make this easier. You'll need to figure the weight of the vehicle (technically, the force of gravity and momentum), force applied by positive and negative acceleration, etc.

.

I considered every possible force this area would have to take, and designed the repair accordingly. The mounted bushing prevents side-to-side motion, so I concentrated mainly on up/down and forward/backward forces. The L-shaped steel (or iron, not sure) is much heavier than the factory metal, and should be able to withstand some serious punishment.
Yes these unibody chassis' are certainly not easy to repair.

[Epistemology]

Well, you sound like you understand how critical work like this is on a car. The only thing I might suggest is calling around to different state inspection garages to see how they would want the repair done. Depending on how conspicuous the repair is during a visual inspection and how fussy the shop is, you may have trouble getting it inspected.

[packrat79]

Well, all I know for sure is that you can't be too careful with something like this, that's why I'm overdoing it as much as possible. If the inspecting technician is concerned about this area (which will be all but completely enclosed by then) I can always show him some pictures of the repair process. And if he still has a problem, I'll just take it somewhere else.

[MagicRat]

Congrats on tackling this kind of repair on your own.

Just a couple of points...... your welds look a little rough. Sure its tough arc-welding thin metal but try using an angle-grinder to grind off all the rust on the surfaces to be welded. The welding surfaces must be shiny and clean. You will find the rod will stick much less, you will get a nicer weld bead and generally be much easier to to use. The results will be stronger too.

Also, knock off all the slag and follow up with a 'filler' rod like a 7018.....