AWD Rack and Pinion install

[photo_van]

Well a Durango R&P unit finally fell into my lap so I figured I should do something with it. Timing really couldn't have been much better as I recently snapped off the drivers side idler out in the way back. But that is another story (Astros will steer with only one idler as long as you tie the broken one up out of the way), heck, steered as well as these vans ever do!

I had decided on a Durango R&P some years ago, due mostly to the fact they use the same size hose fittings as our vans and that magically the hoses might work. Also the Durango has 7" of travel, more than enough. Lastly the mounts are toward the bottom/rear rather than the front which I thought would lend itself better to the mounting arrangement I had envisioned.

Durango R&P with tie rods removed

I live pretty remotely so I wanted this project to be as simple as I could make it with the least amount of fabrication (though there is still plenty). This project involved some liberal use of a cutoff wheel on an angle grinder so if you are squeamish when it comes to cutting chunks of metal off your sub-frame you may wish to stop reading now...

I had seen where a guy had pulled off something similar on the other forum. He did an immaculate job but had the benefit of a sub-frame sans body. I was hoping for something a little simpler that I could hopefully pull off "in car." This project was also carried out using simple tools (with exception to the lathe: the aforementioned angle grinder, tablesaw with cutoff wheel, lathe and of course the standard array of hand tools. The van was never jacked (ramps only), and the only parts that needed to be removed (that weren't being discarded) was the swaybar (to allow removal of the OEM steering box). Also, this is my garage.

And this is my work bench

Before I got into this project to much I had to do a little research on steering geometry, and soon after I learned that a "plug and play" option was out of the question. Rather, I would use the R&P to "drive" the existing Astro crosslink and tie rod ends. Doing so, I would eliminate those damn idler arms as well as the steering box and draglink; this cuts the number of moving joints from 10 to four and by using the existing crosslink and tierods there would be no need to ream the steering knuckles and all the OEM geometry would be retained.

I had hoped to mount the R&P to a"simple" mounting frame bolted to the front lower control are pivot bolts. But after pulling all the OEM parts out and holding the R&P in place I found that it would need to be rotated forward slightly, so mounting was going to be a little bit more problematic. Also, because the hose ports are to the rear I would need to whittle away a little at the left front diff frame mount.

[photo_van]

One thing I was/am really concerned about is the possibility of the lower control arm coming in contact with the rack extended and suspension in full compression. To minimize that possibility I wanted the rack as far forward and as high as possible. This required removal of a bit of steel from the lower drivers side control arm mount. Really just a small piece, what could possibly go wrong?! :-k

I'm thinking it will be just fine!

Now that the R&P fit where I wanted it I started fabricating the mount. The control arm bolts are just long enough that a leg of quarter inch angle will fit behind the nut I then had to notch the angle and bridge that with a piece of 1/4" flat stock at about 30° to fit the angle of the R&P mounting. This was the only welding that was necessary. I'm not big on welding under the van upside-down which is why I chose this mounting method, it allowed for the welding to take place on the bench. The mount can be seen in the bottom of photo. (BTW, that is all the necessary fabricated parts)

[MountainManJoe]

My new van has R&P steering and I hate it. It tries to break my fingers off when I'm driving over logging roads. I miss the Astro steering, even if it did eat idler arms.

[photo_van]

Next up was to tie the crosslink to the rack. The unfortunate thing about the Durango unit is the tie rods have M24 1.5 threads. This is a big bolt that will need to be treaded into the ends of the rack. Those bolts if you can even find them are $$$. I found some mildly hardened threaded rod at McMaster. At $80 still not cheap.

After halving that it was time to see my friend with a lathe. Sleeves needed to be created to both lengthen the rack and provide a surface to mont a dust boot on. From the other thread I saw that Rancho shock boots would fit and I happened to have a couple left over from the front shocks on the van. My friend is a high end guitar builder so consequently a precision machinist. Since the boot had two ribs he made two notches to fit. He also bored them tight to fit requiring heating in the oven to 170°

Next I used some 1/4" 2x3 angle for the brackets. This was the only metal I didn't get from the scrapyard which was a mistake. I ordered from McMaster and got this.

As you can see, not square. We put it in the press to straighten.

[photo_van]

I was to mount the crosslink using the idler arm holes which are tapered and needed to be drilled for a 9/16" bolt (I forgot to include drill press under tool list).

I was going to use a a 9/16 drill but Mark insisted on using his lathe and grinding post to make an slightly undersize drill for a tight fit.

I purchased long grade 8 bolts so there would be non-threaded shank in the hole and cut them to length.

We squared off the end of the crosslink so it would be snug against the angle iron and threaded the hole for a nice tight fit, the bolt will be backed by a nut.

[photo_van]

I sure hope I like it Timeless, it is a LOT of work!

[mdmead]

Very cool! I'll be anxious to hear how it works out long term. Obviously my van is far from being on the road, but this is an upgrade that is on my radar for the future.

[Captn. Crunch]

Rack and pinion? Quite an undertaking and I wish you well. I’m strictly a swap and bolt kind of guy and have always marveled at those with fab skills. I can’t wait to see the finished product!

[photo_van]

Got the fab smoothed out and ready for a mock up

Some tight clearances on the swaybar bushings and hose fittings so a little minor tuning then made up the crosslink bearing cairrage.

This mounts directly to the R&P mounting bolts and keeps the cross link from wanting to rotate on the rack

Ready for install

[photo_van]

With some bending the Durango lines work perfectly at both ends

Clearance on the passenger side is fine

on the drivers side I had to trim the balljoint stud and remove a little casting rib on the R&P

Next came the steering shaft. Here I used the top of the Astro shaft and the complete Durango shaft. The end of the Astro shaft fits well after filing one side flat and putting in a notch for the clamp bolt.

The upper Durango shaft fits perfectly in the 1" pillow block bearing.

[photo_van]

I had to shim the pillow bearing out a bit so the middle u-joint cleared the ECU

finished install

So how does it drive? Is it a miracle? Well, if I never have to hear the crank pulley grinding on the cross link ever again, then yes! It is firm and very responsive and I only have to grease 4 fittings now! At first it was almost two firm and didn't like returning to center after a very minor turn but that seems to be loosening up now. I like the way it handles off road so far. I think lower control arm clearance could be an issue. While there is clearance to the rubber stop, I think if the suspension bottomed really hard and compressed the stop there could be a little contact, hard to say. I avoid driving my rig that hard so I hope to not find out, your mileage may vary. For less than the cost of two Moog Idler arms, Id say well worth the effort.

Boot mods below

Have your lathe guy turn a PVC fitting to press into the pillow bearing

Drill out a Bush Baked Beans can to fit. Gotta be Bush! 3" can fits the lower end of the Astro boot. The upper end of boot will need to be shortened using the 2" PVC method.

[photo_van]

***update***

I took it out on some pretty rough 4x4 roads and it performed flawlessly. I managed to get one front control arm bottomed out solid and still had an inch of clearance between it and the rack. So far so good!

[MountainManJoe]

did it spin your steering wheel when going over bumps?

[photo_van]

It hasn't kicked back on me yet but I haven't had it in real rocky terrain yet.