The leaf spring mounts at the front of the rear springs on my Econoline are badly rusted and are pulling away. I need to rebuild them, but I'm unsure of what gauge steel to use. It looks like the original was 1/8" or thinner. I'm thinking 3/16" tubing would be sufficient, or should I go with overkill and use 1/4"? The main rails are very crusty, but otherwise solid. The supports that go from the rail to the inner rockers are obviously shot. The spring mounts that actually attach to the leaf eye, seem to be OK, but I may build new ones anyway. The van has a regular 302 v8 and is mainly a driver, but I want to hit the drag strip a few times a year for fun... that's how this damage happened.
Is there some reason why you want to use thicker material than original? The original design works fine...unless you let it rust away....
Well, 1/8 seems pretty thin. It worked great for a 170ci inline 6, but would it hold up to a 302 with a POSI under heavy acceleration? That's what I was thinking of upgrading to 3/16", but I'm no engineer.
I doubt you'd find anything thicker on cars like the 427 fairlane, etc. The design uses a tubular shape (hat channel welded to the floor), so it can be very strong using thin material.
1/8" should do it. You might want to get some pieces bent up by a shop which would give it even more strength. Make some cardboard templates and see what you think. Bob
Obviously. That's why I won't be doing the welding. Would I be better off bending up a hat channel, or using rectangular tubing and welding that to the floor?
You might want to think about replacing the plumbers strap that's hold your gas tank up with something more suitable.
Either way would probably work, but tubing would probably be a lot easier to do. Just be sure to also replace any other parts that might be weakened by rust.
That strap, IIRC, is rated at something like 600 pounds, and I have it doubled over, and there's one on each end of a 15 gallon tank. One of these days I'll bend up some straps Yes, Squirrel, there are a number of areas that are rusty. The floors above those supports are also bad. I only recently realized how important those areas were. So that section of floor and the adjacent inner rocker area needs to be replaced. Actually, the area where that support attaches to the rocker is ok, but the lower part is bad. The inner rockers on these vans are huge... like 12" tall. Those would be the areas that need the most attention. Oddly, the area between the rails is very solid and relatively rust-free (a lot of original paint was still visible), but the area between the rails and the rockers is rusted to pieces.
The problem with plumber's strap is it seems to break in time, any flex and it eventually snaps off. The last time I had to rig one up I used regular plant or picture hanging cable from Wal-mart, stuff rated for 300# and like 3/16ths thick. The only thing that would scare me on that van is before I spent much on it I'd go over all the rest of the underside because you don't want to chase a little rust, and have to chase a little more rust, and more, and before you know it you've rebuilt the whole underside of the van and spent enough you could have bought a better one - which isn't that hard to do on these vans, I had a chance to swap for one and when I saw what they sell for I passed.
Actually, it IS really hard to find one in good shape, especially in the Midwest. I looked for years for one. If they're in decent shape, they're on the West coast, and shipping alone will be more than the van is worth. It's even harder now that these things are popular again. Anyway, I have most of the patch panels and replacement parts I need, and know where the damage is. I just overestimated how long that section would hold up, and underestimated its importance! Thanks for the tips though.
Being that I just finished up doing a five inch bodydrop on my econo I can pretty safely say that's a big job any way you look at it. I've seen what your capeable of...you got this. What I would do myself is take the bolt out of the spring and drop it down and out of the way. Get out your drill and drill every spot weld holding each of those crossmembers one at a time. Go get yourself some 2 1/2x4 box steel, I think it is, and cut to lenghth the pie e your replacing. Probably a good idea to weld some 1/8 inch plate that covers a bigger area than just where those ends will be butting up against that fifty year old metal. Reweld through all your spot welds and even do extra where you can. Man, you got this!
I took some measurements this weekend. The original metal was only about 1/16 thick! I don't know what gauge that is, but upgrading to 1/8 seems like a good idea... or 3/16 since I already have some. Sure, it's overkill, but when is that a problem? Like my grandfather-in-law used to say "You'll never know if your build is too strong"
Brilliant! Must have been either a "Jack of all trades" or a mechanical engineer. My dabloons are on the 1st one. Hey Hellfish? Just curious...... have you looked into replacement parts? Knowing how good Henry was at using the same parts in alot of different models, I was wondering if something wasnt available "off the shelf".
Seems to me that attaching thick stuff to thin stuff is not really the best way to go. I'd consider buying some thinner tube for it. 16 gage is about 1/16" thick.
Mechanical engineer. He designed some massive machines... then designed the machines to build those machines. Econolines were built with the thinnest, cheapest stuff Ford had (think "Econo"). They were virtually the same from 1961-1967, but share very little with anything else Ford produced, and not much is reproduced for them. I think the actual pieces that the springs are attached to are strong enough. I just need to replace the hat channel they are attached to. Why is that? My thoughts were to attach some thicker tube to plate to give it more of a footprint instead of thin to thin.
My thinking is that when the thick part is loaded, it will not flex itself, but will cause the thin metal it is attached to, to flex right next to the weld. If you use thinner metal, it can all move around a little bit together, thus not trying to crack the metal next to the welds. But I could be wrong....it's been a long time since I went to mechanical engineering school.
1 day is more than I had. I was just curious. Thicker seems better for structural rigidity, especially if spread out over a larger area, but I really don't know anything. Thanks for the thoughts/advice
I just remembered that the thin hat channel has some sort of thicker rectangular tubing welded inside it. I'll have to get back under there and re-assess it.
your 100% correct .Trying to over engineer one part tends to cause major faliur elsewhere just my two cents
No progress. I've been trying to get my wife's Corvair back on the ground so I can get the van into the garage to start work. The hat channel is 3.5wx4h. I can get box tubing in 3.5 x 3.5 in 11ga(.120 wall) or 4x3 in 1/8 (.125) wall (or the same sizes in 3/16). Either way it will take some additional work, but fairly simple. 11ga just seems too thin... even though it's probably thicker than stock. I'll try to post some pics tonight
The original floor pan was probably 16 gauge sheet metal. The original hat channel was also probably 16 gauge that was either doubled or had a thin wall tube welded inside (or in some cases outside) at the point the shackle (or any other stress creating item) was attached. The additional material was probably only about 6" long, unless something else was attached to the hat channel very near, in which case they may have had a little longer inside piece. There is also a tube welded through the hat channel for the shackle bushings to mount in. The additional tube for the shackle bushings eliminates the need for thicker wall hat channel as it keeps the hat channel from crushing or twisting. The flanges on the hat channel also spread the load out. The issue you have is the hat channel walls have collapsed from rusting away and the floor pan at the flange welds has also rusted away, which allowed the hat channel to twist. Reality is, your probably going to have to piece another section into the floor pan to replace the damaged section. If the hat channel was 3 1/2" wide, and the flanges that were spot welded to the floor pan extend another 1/2" out per side, you will have to at least replace a 4 1/2" wide section of the floor pan, but I suspect that replacement section is going to need to be at least 5" or 6" wide and several inches long. You have to replace as much of the floor pan (width and length) as it takes to get to rust free steel. The repair of the floor pan is as important as the repair of the hat channel. Cut out the rusted floor section, but repair the hat channel before you replace the floor pan. My sugestion on the hat channel is to get tubing that will fit inside the un-reinforced hat channel's width and as close to the same height as possible (a bit shorter is better then too high). The hat channel repair has to be longer then the damaged area (again, you need to get to good rust free steel). I suggest when you reach good steel on the hat channel that you cut about 2" of the bottom surface off the hat and slide the new tubing inside the original hat channel ( shim the sides between the tube and the original hat for a nice fit) on both sides. If the floor pan replacement opens up the hat channel you can drop the tube into the hat channel from on top and not have to cut the bottom out of the tube. The most critical position of the tube is to be in contact with the sides of the hat channel and flush with the floor pan. It the bottom of the tube does not match up with the original bottom of the hat channel, a small piece of metal can be used to close the gap. Then you can weld the tube to the hat channel. When you replace the floor pan, drill two rows of 1/4" holes through the pan above the tube near the edges of the tube and plug weld the pan to the tube about every inch or so apart. Then weld the edges of the floor patch in. If done in this manner, it really won't matter how thick (11 gauge, 12 gauge, or 3/16" wall thickness all work) of tubing you use. There needs to be a round tube welded to the rectangle tube for the shackle bushings to sit in. Be sure that round tube will be in the correct position on the finished product. I've been doing rotted out frame repair for 16 years here in the Midwest, and this is the method that has proven to be the best repair for long term repair. Gene
Don't repair it. Build a full frame and a new floor. Faster, cheaper (in the long run, you will discover).
Gimpy, there is only a small section that needs to be repaired. The rest of the "frame" is solid. Thanks, Gene. You are right on all counts. There is not really enough of the hat channel to work with, so it needs to all be replaced. The part that holds the spring eye seems to be solid. It's just the hat channel that's toast. Here are some pics of the "good" side. and here's the "bad" side
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