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I am doing a lot of changes to my van at the moment. The background on it is I have a AWD 95 lifted and 31's as well as a 5.3l conversion I did about 6 years ago. Van has been great but the 95 body has finally had the biscuit. It has rotted out where it mounts to the frame and the drivers side was 1.5" lower than the passenger side. The body has about 475,000 km on it so im not surprised its done considering the salt we have here in Alberta and the countless off road trips I have done with it.
So it was time for a new body, I found a nice 2000 RWD as the donor. And so at the same time I wanted to tackle the list of improvements that I have made over the last 6 years and 100,000 km of driving the van. I will dedicate this post to the rack and pinion mod, but here is a list of the other things I had on my list, I will post links to them as I make other threads regarding these mods for those who are interested in the other stuff.
1. Convert to rack and pinion.
2. Replace Body 95 awd to 2000 RWD body.
3. Build sub frame connectors And Do the body lift properly ( welded spacers on frame) viewtopic.php?f=127&t=91113&p=882777#p882777
4. Install some electronics / Deck with rear view camera/ Marine Charger for 3 batteriaes / External plug for 15A 110v for gen set or camping spot/ Roof rack spot lights with remote/ LED roof rack tail lights ECT ECT.
Before I start my rack rant I need your help. I need the pin out for a couple connectors on the 2000 Astro donor body. I cant seem to find the info or even the name of the big firewall connector. Please go here and help me out if you can. viewtopic.php?f=76&t=91057
Here are the pics of the connectoer I need help with.
And this one as well
OK NOW ON TO THE RACK MOD
I have not seen anyone do a AWD Rack And Pinion Conversion yet. However I did see someone do a RWD using a Mustang rack somewhere on here. From what I read they did not take the geometry of the steering into consideration, and the vans had weird steering and bump steer issues.
I'm familiar with the Ackerman steering geometry theory as well as bump steer. So I thought id try my hand at doing a AWD conversion and try to get the geometry close and the van to drive normally. This is important to me as I do a lot of trips with it. So here is what I came up with.
I had a Mustang rack from my brothers car and quickly found out that even though the inner tie rod joints were almost exactly the distance of the Astro inner joints the rack could not be placed in the proper spot to avoid the bump steer and to get the Ackerman angles right. The Front diff as well as the diff mounts are simply in the way. The other issue was if it was placed in the right spot somehow the steering shaft comes out right under the PS pump. Other problems included the mounts being in totally the wrong spot as well as the steering shaft would almost have to go backwards from the fire wall or two shafts would need to be made and with a intermediate bearing and shaft to tie it all together.
So I went on a search of the internet and junk yards for something that would make sense. I had a idea in my head it was just a matter of finding the right donor rack. Well I found one, it is from a 2005 F150 4x4. I got it from the junk yard for $35 and its in great shape.
On the truck it is bolted to the front of the frame where I thought would be a the perfect spot for the Astro as well.The Ford f150 Rack is very heavy duty compared to the Mustang unit, and it has 6.5" of travel VS the 6" of the Mustang which is barely enough for the Astro. Also the bonus is the tie rod ends can also be used and are almost twice the size of the Astros.
The rack is very big and long so to make all the geometry work I knew i would have to make a bar which would attach the tie rod ends in the positions they needed to be. I seen this on some Hot Rod conversion rack kits out there so that's where I got the idea. Those racks are $1500 to $2500 however. And probably more for a custom one made for a Astro project.
Anyway here is some pics of the progression of the build.
First I measured the angles of the stock tie rods. They are angled back from 90 deg. That is the Akerman steering. They are also angled the same angle as the A arms for bump steer.