Straight axle breaking

What part is breaking? Can you post a photo of it?

I have four of these, '88, '89, '94, and a '95, with a total of over 900,000 miles in one of the worst states for using road salt in winter. None have developed a problem, but I did weld one up many years ago on a mid '80s car for a different problem. The minivans use a much beefier rear axle than those used on the front-wheel-drive cars. See if you can point to the problem area in this drawing.

The best repair would be to find a used rear axle assembly at a salvage yard and do a transplant. These really don't develop many problems, so your chances of finding a good assembly are very good. If you go this route, one thing to watch for is if you're in the rust belt, metal brake lines are likely to be rusty. You may find it easier and faster to unbolt the brake backing plates and bolt them onto the new axle. If you do that, watch for thin steel or round plastic shims between the flange on the axle and the base of the spindle. Those are alignment shims. There's no way to know what needs to be put back in without having the alignment checked. It's pretty common to find no shims in there. It all depends on how picky the last alignment specialist was.

I added some nifty arrows to the drawing. Are you saying the tube is rusting apart by the pink arrow? If so, I don't know what would cause that, but I do understand your comment about adding a piece of pipe around it. That's something no professional would do on a customer's vehicle, but I have done worse things to my own cars over the years.

If you were to find a short piece of pipe of the right inner diameter and cut it in half lengthwise, that could be placed around the axle tube, but I wouldn't trust clamps to hold it.
I'd weld it with a wire-feed welder. There's some points to consider though. That tube is going to be not very thick, so burning through it will be easy. One of its jobs is to hold the side-to-side dimension between the two rear wheels, and to hold the wheels straight and in alignment. Without that axle tube, the wheels can tip in and out on top, (camber), by twisting the leaf springs, and they can turn their direction of steering left and right, (toe). The weight of that corner of the van will actually be held up by whatever twisting strength there is in the leaf spring. Leaf springs aren't designed for that. They're only designed to flex up and down.

The good news is there isn't a lot of stress near the middle of the axle tube. Also, if it is still at least partially intact, you have the correct dimension, and the alignment angles, camber and toe, should be correct.

The way I would pursue this on my own vehicle would be to lay in half of the pipe, weld it on the ends and at a few places along the middle, then set in the other half, weld it on the ends, then at a few places along the middle to the first half. Keep in mind the axle tube wants to twist a little when one rear wheel moves up into the wheel opening while the other wants to drop down into a pot hole. The same thing happens when you support the van unevenly on jack stands. To prevent introducing a new stress, support the van with jack stands under the frame rails and let the axle hang freely. There's enough flex in the leaf springs to let them bend rather than forcing the axle tube to try to twist.

Remember, this is not something we would do for a customer. This opens us up for lawsuits even if the repair wasn't a contributing cause to a crash. It is also not factory-approved. If you don't have access to a wire-feed welder, replacing the ale assembly would actually be easier as it's just a big bolt-on item. Removing the brake backing plates involves four bolts on each one. No need to remove rusty steel brake lines, wheel cylinders, or parking brake cables. Everything just gets transplanted onto the new axle tube. Four bolts to remove the two anti-sway bar brackets. Probably the hardest part of the job is removing the four leaf spring U-bolts. Those nuts always seem to require a lot of effort to turn them, and the U-bolts are always much longer than they need to be. Regardless if you remove them with a hand ratchet or breaker bar, or with air tools, those nuts will be hot when they come off. This is where most people buy new U-bolts and nuts. They go together much easier. When you're paying someone to do this, it can cost less to cut the old U-bolts off and throw them away. The cost of new bolts and nuts is less than the dollars you'd spend in labor time to unbolt the old ones.

If you're lucky enough to have access to a plasma cutter, the job gets still easier. They're faster and cleaner than using a cutting torch. At a salvage yard, it takes them longer to haul a van into the shop than it does to remove an axle assembly. In five minutes they'll have it out with time left over for a coffee break. Sometimes it just pays to let the professionals do what they're best at, and I stand back and watch.

Let me know what you think of my ideas, and how you're going to solve this.

I need to get rid of some of my vehicles. Are you anywhere near north central WI? I don't like the thought of sending these to the scrap yard, but my two older vans are so rusty, the carpet is the only thing holding the front and rear together. I'd love to head south and find a nice rust-free '88 Grand Caravan with 15" wheels to replace my old one.

You might also consider using some flat stock and welding a couple of pieces of that across the break. We have a metal supplier in the country that has buckets of cutoffs and other odds and ends sitting outside. Used to get ten cents a pound but I heard that has gone up quite a bit. I found ten and twenty-foot lengths of square tube to cut up for railings in my shop at real good prices. As long as your axle tube still is holding the right dimensions, adding these pieces might be a cost-effective alternative. There have been other, lower-quality, factory-approved repairs mandated under recalls years ago. One that I was involved in around the early '90s didn't address the early rust. It just involved adding plates to hold the front wheels if the cross member broke so you wouldn't go sailing into the ditch or oncoming traffic. Ford also has a problem with rear axles on Windstars. Don't know what their fix is, but I did hear owners have had to let their vehicles sit for a long time while waiting for backordered parts.

I'm in Wausau.

The 2.5L was a really nice four-cylinder engine, but they only came in the short wheelbase. I need the Grand so a 4' x 8' sheet of plywood fits inside. Also, with 15" wheels you got bigger brakes. I used my van to drag a tandem-axle enclosed trailer that's bigger than the van to the Iola Old Car Show for 15 years. Never needed the trailer brakes. '88 was also the last year for a speedometer cable. '89 and newer needs a troublesome sensor and two computers to run the speedometer.

As for your pipe, I used a metal-cutting chop saw to get the job started, then finished it with a 4 1/2" angle grinder with a thin wheel. I cut open a 3 1/2" square tube to lay each half over a pair of trusses in my garage. Those were the base to weld on posts to form the frame for a railing. That tube wasn't very thick. I don't know gauges real well, but I'd say the steel was only about 1/16" thick, so it cut pretty easily. That would be enough thickness in a round pipe to meet your needs.

The problem with going too thick is in welding the pieces together. You won't get enough heat to melt into the new piece, but you'll have too much heat and will burn through the axle tube. If you're a good welder, you can turn up the heat, then run the bead mostly onto the new piece. Allow just enough heat to reach the axle tube to penetrate but not burn holes in it.

You'd be surprised to see how thin the axle tube really is. On the car models, they didn't even use a tube. It was a flat sheet, less than 1/8" thick, rolled into a three-sided strip. It was intended to twist to partially isolate road shock from transferring from one wheel to the other for better comfort.

The only other options are to replace the assembly or have someone else weld the repair. In the case of my '94, it doubles in value every time I fill the gas tank.

I've never done this but if I did, the only way I can achieve a decent weld is when both pieces are roughly the same thickness. I can make two pieces of metal stick together with a stick welder, but it usually isn't pretty. A professional would not be impressed, but I can get the job done. The axle tube is thinner than you would expect, so I'd use a thin patch and a small electrode, as in 1/8 or even 1/16", and a low current to prevent burning through the tube.

Wire-feed welders can make poor welders look good. I'm no exception, at least once I get the speed and heat set right. They don't cause as much sticking as does stick welding, and it's easier to run a nice bead.

You gotta remember, there isn't much stress in the center of the axle tube. From the center out, it's just a big lever that's holding the wheel straight and in alignment. It's not going to take much to hold the break together.