astro axle swaps

[357astro]

has anyone tried or know anything about putting a full size chevy van (g10 or 20) axle under the astro? i have seen the info and pages on the 9in swap. but i was wondering about this. i swapped my composite springs out over the summer for the steel cuz i kept breaking them. now my problem is that the rear end is basically winding up under hard (stoplight exhibitions ) acceleration and is causing binding at the pinion yoke and has essentially destroyed the mounting on the axle housing once again allowing my axle to slightly rock when i apply excessive torque. just weighing my options.

james

[NotDadsW41]

Not sure the full size vans will work, given the offset of the Astro rear ends.

[357astro]

but don't the full size have the same type of offset? i know on one of these forums i saw a pic of an astro with this done, but no info. was hoping someone knew this person or of the pic i am speaking of.

[Mr_Roboto]

Peter measured a corporate 14 bolt under an Express/Savanah van for us, it wasn't offset like the vans are. I would have much rather thrown a G-van axle underneath, as they were an 8.5 which is not only lighter but at the same time retains the lug pattern and is a very heavy duty axle; that being said, hit the salvage yard your milage may vary on this. I'm wanting to say I mesuared a G-van axle and it wasn't going to work though due to the pinion offset to the passenger side.

[LiftedAWDAstro]

Sounds to me like you don't need an axle. You need a traction bar! If you slap a heavier axle under the same set of springs, you are just going to have the same result. Remove the stock axle, repair the mounts and fab up a traction bar. All your axle wrap and leaf spring breakage issues will be cured.

[357astro]

i was thinking of the 70's to 95 or so vans. i thought they had that offset too. i know on one of these sites or somewhere i came across a pic of an astro with that axle. i could very well be mistaken as my fiance reminds me quite often. Seriously, my problem i keep having is with the way the stock axle mounts. i can't seem to keep the axle from trying to rotate against its brackets. i am actually going to remove that setup and switch it to the style that is on the 88-98 fullsize pickups, like in the picture without the lift block though.

[Mr_Roboto]

This is mine. Please note that if your axle is at this angle it is NOT RIGHT. I also ended up shaving 1/8 inch off of the brackets to clearance the frame, they are otherwise stock 9" plates up top and U-bolts.

[LiftedAWDAstro]

James, I will still stand by first answer. You will not get better results with a different style mount. The soft leaf springs are what is giving the axle wrap and causing the issues. What you can do in the mean time is remove the rubber cushions on top of and below the leafs. This will eliminate some of the flex but most will still be there. Adding a simple traction or ladder bar will eliminate the axle wrap issues.

[357astro]

I agree with you lifted, a traction aid such as a bar or something to limit my axle movement is what i need. I was just looking for other possibilities for axle replacement to better take the periodic abuse. And since my current axle mount is fubar, i just figured i would switch it over to further facilitate the fabbing of the traction aid i choose. I use my van for quite a bit of towing, pulling and just plain messing around. The looks on the faces of those that get their grinning, cocky faces wiped clean by a loud minivan is priceless. The rubber mounts that came on the springs were'nt there when i did the swap to them, so that part was 1st completed. I had the factory astro mounts tightened down completely when i did the swap, but they have since bent and/or cracked and been repaired once only to do it again. I really appreciate all the input so far.

[zook94]

Ok, my secret weapon is coming out. The solution takes some work, but will be the end of your axle blues.

The rear axle I am going to run is a Dana 60 out of a 1967-1979 J-20 or J-30 Jeep pickup with a Quadratrac transmission. The front and rear outputs are both located on the right side of the truck, offset just like the Astro. Some work needs done, as the axle is too wide, but by cutting the long side down, and sleeving it with 1/2" schedule 80 pipe, and grinding a chamfer on the weld surface, you will end up with basically indestructible parts. The rear axle is 1-1/2" 31 spline, comes with tons of aftermarket support from full spools to air activated locking mechanisms, and the axle is full floating design, so breakage won't leave you stranded, depending on your choice of traction control.

Moser engineering will cut your existing axle shaft down to match your shortened housing for $65USD. The native bolt pattern is 8 lug on 6.5 inch circle, but can be re-drilled to any bolt circle you wish for not much more moneys. I'm leaving mine 8 lugs in place, because my 472 will need all the extra strength it can get to keep it in one piece..... another story for another day.

Check into these axles, as they are fairly plentiful, as long as you don't live in California, where they scrap anything that doesn't move within a half hour. I paid $50 for my axle.

(steps away from podium)

[Mr_Roboto]

472 you say? Any pics? We wanna see Caddi action!!!!

[peter]

I had run thru this thread earlier but didn't have time to respond. I do now, so watch out.

I had loads of issues with my rear axle-attachment set-up. Throwing a lift block seriously screws up the integrity of the clamshells and their ability to properly secure the axle. I originally scrapped the clamshells 'cause I was smarter than GM, but the pothole I hit made me realize why the clamshells are there to begin with.
So I was screwed. I needed to keep the clamshell set-up, but I also had to address my severe axlewrap problems (a v6 can be a problem, a big block magnifies the issue by 10)

After many attempts, I finally settled on the following. I've had no issues whatsoever with this set-up.

Keep in mind that the axle shown is a custom Ford 9" built to my specs. The axle perches came from Bear Performance as well, and I'm not quite sure if they're off-the-shelf items which mimicks some car manufacturer's design...

This is a pick of my set-up when I decided GM had no reason for using clamshells. Funny, the top plates look identical to those used by Roboto



This pic shows where potential clearancing issues are. I shouldn't say potential, for that would impart the idea that it's only a possibility that there would be a problem. Altghough Robo swears he's never had an issue with these plates, I definitely did...every time I'd hit a pothole..



This first pic is solely for the purpose of showing off....



EDIT:Here you can see the modded clamshells in place. I've since straightened out the u-bolt angles and cleaned up the general look, but this is pretty well it. When you don't run the clamshells and use a typical top-mounted plate to hold the u-bolts, the plate and/or u-bolt tips & nuts wack against the frame just above it when the suspension flexes enuf.





Modded clamshells. Simple really. I added to their total height so as to accomodate the lift blocks.




The completed set-up. The only thing I don't like about this set-up is that if I ever have to torch the u-bolts holding my traction bars, it'll be hell installing new ones. It's been awhile so I'm going from memory, but I think I'd have to un-tack the u-bolt saddles so as to allow replacement of the u-bolts. Yeah, that sucks. Small price to pay for standing up to 500 horsies though....

[LiftedAWDAstro]

The rear axle I am going to run is a Dana 60 out of a 1967-1979 J-20 or J-30 Jeep pickup with a Quadratrac transmission. The front and rear outputs are both located on the right side of the truck, offset just like the Astro. Some work needs done, as the axle is too wide, but by cutting the long side down, and sleeving it with 1/2" schedule 80 pipe, and grinding a chamfer on the weld surface, you will end up with basically indestructible parts. The rear axle is 1-1/2" 31 spline, comes with tons of aftermarket support from full spools to air activated locking mechanisms, and the axle is full floating design, so breakage won't leave you stranded, depending on your choice of traction control.

I too used a Dana 60 rear axle for my Astro. It came from a 1990 - 1991.5 Ford E-250 van. It also is full floater and 8 lug. It was the correct length and offset for an Astro or Safari. The wms-wms width is about 67". How wide is the Jeep J20 axle? It should be the right width as it is a full-width axle too. The stock Astro/Safari rear axle is about 67" wide.

[zook94]

472 you say? Any pics? We wanna see Caddi action!!!!

Sorry to disappoint,but my 472 is a BB Chevy based off of a 79 454.

The axle will need narrowing because I am tubbing the rear for more rubber meets the road action, and want the side door to still slide past the tire, and its getting lowered at least 4 inches. Yeah, I got some work to do.