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Chevy Astro Steering

Discussion in 'Builds and Fabricators Forum' started by jayhawkclint, Apr 22, 2011.

  1. Apr 22, 2011
    jayhawkclint

    jayhawkclint ΜΟΛΩΝ ΛΑΒΕ

    Oklahoma City, USA
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    Today I started the Saginaw conversion on my HEEP in order to accomodate a Buick V8 swap that is going to use manifolds. After considering a number of options, I finally settled on mounting a Chevy Astro steering box behind the radiator/grille crossmember. I haven't found a whole lot on the web about doing this in an early, so this thread will chronicle my learning curve.

    I picked my box out of a short wheel base cargo work van. I picked a vehicle that still had the steering connected and was able to check the ratio and test for slop. The box seemed to be in good working order and has a ratio a tad over 3-1/2 turns lock to lock, whatever math that works out to.

    Unrelated to picking this Astro box, I also happened to have a Jeep ZJ Grand Cherokee box that had been sitting in my garage for quite some time that had been intended for a previous hot rod project. I think it was from a '99. Make sure to take your Pitman arm puller with you to the boneyard so that you can pick and choose the right Pitman arm for your ECJ5 with your steering box at time of purchase - my local yard charged me $35 for box and Pitman arm together.

    Box on the left is Astro, box on the right is ZJ. Also shown in the pic are some brackets off an intermediate CJ that will be used to secure my postal column:

    [​IMG]

    I swapped the ZJ pitman arm onto the Astro box. It has a drop of about 3-3/4" or so. Also of interest is the ZJ mounting bracket. It is a 3 hole bracket, just like the Astro, that will provide the necessary spacing to mount the Astro box against a flat surface, like a section of ECJ5 boxed frame, for example. It is the triangle shaped piece on the ZJ box in the picture above.

    After removing the Ross box and drag link, and grinding the driver side upper shock mount off the frame, I was able to set the box in place for some measurements. Note the stock Astro double u-joints and short shaft. It is *SO CLOSE* to fitting the end of the postal column as-is. Might just need to cut a slightly longer piece of steering shaft, will have to wait until final installation. Also note test fitting of the F250 shock mount in a behind-the-axle configuration. Eye-to-eye measurement increased to over 27" as it sits! Could probably get 29" if I massaged the inner fender:

    [​IMG]

    Here is a rough idea of the Pitman arm position relative to the frame and drag link. Waiting for the "point of no return" before I cut the bell crank off:

    [​IMG]

    Now I need the experts' help. I want to put a little bit of angle on the box so that the shaft clears the engine mount and drop the front of the box just a hair below where it sits in the pic above. If I do that, I'm going to have maybe 15 deg of down angle and the top hole of the box will stick up just slightly above the frame where the old shock mount used to sit. Looking for suggestions on the best way to do this. Thinking a piece of 2" square tube welded to the top of the frame, plated, then drilled and sleeved, and use the stock ZJ spacer to mount the Saginaw box flat to the plate. Other ideas?
     
    Last edited: Apr 22, 2011
  2. Apr 23, 2011
    w3srl

    w3srl All-around swell dude Staff Member

    Port Orange, FL
    Joined:
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    I'm curious Clint as to why you went this route instead of the traditional Saginaw conversion method. Not that the Astro box isn't a good idea, but it just seems like it will make an already tight engine bay that much tighter.
     
  3. Apr 23, 2011
    jayhawkclint

    jayhawkclint ΜΟΛΩΝ ΛΑΒΕ

    Oklahoma City, USA
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    Well, I really like Herm's kit, but the Ford reverse boxes are getting really hard to find. Also, I really didn't like the way my steering shaft was going to get notched through the engine mounts and radiator crossmember. Plus, I'm using a late AMC grille and radiator which gives me a little extra room, and my Buick Wildcat PS bracket mounts high up toward the valve covers out of the way of the steering box.
     
  4. Apr 23, 2011
    Patrick

    Patrick Super Moderator Staff Member

    Los Alamos, NM
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    I'm surprised the Ford reverse rotation boxes are hard to find . They fit so many Ford products from a lot of years.

    *
    Ford Bronco (Fullsize) 1980-1996
    *

    *
    Ford Bronco II 1984-1990
    *

    *
    Ford E-Series Van (E-150/250/350) 1982-1996
    *

    *
    Ford F-Series Truck (F-150/250/350, 2WD & 4WD) 1983-1997
    *

    *
    Ford Ranger 1980-1997
    *

    *
    Mazda Trucks (B2300, B4000, Navajo) 1991-1997
     
  5. Apr 23, 2011
    pilebuck

    pilebuck Member

    western WA.
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    Seems alot of work.How are you going to run your exhaust ? And i agree tight quarters herms is overated in my opnion but hey as they say whatever blows your hair back.Just make sure to think ahead of future mods like hydralic cluch and other things that might be in the way good for you looking forward to see the finish product
     
  6. Apr 23, 2011
    jeepcj

    jeepcj Member

    cincy, Ohio
    Joined:
    Aug 23, 2009
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    601
    Here is what the PO did to my jeep. I dont have any problems at all with it that way. hope the pics are ok, I had to turn on a spot light in garage for lighting.

    [​IMG]
    [​IMG]
     
  7. Apr 26, 2011
    jayhawkclint

    jayhawkclint ΜΟΛΩΝ ΛΑΒΕ

    Oklahoma City, USA
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    Got out in the garage tonight and did some cutting and grinding. So far all I've accomplished is making a big mess. Here is the start of my mounting bracket. Angle on the box is very close to final, just need to bring the splined end up about 1/8" or so:
    [​IMG]
     
    Last edited: Apr 26, 2011
  8. Apr 26, 2011
    jayhawkclint

    jayhawkclint ΜΟΛΩΝ ΛΑΒΕ

    Oklahoma City, USA
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    I will have to look into those boxes again the next time I'm at the junkyard. When I bought my Ford box about 2 yrs ago, I remember checking A LOT of trucks, and only found a '79 Bronco that had the correct box. I don't remember checking the Econo Vans, but that would make a lot of sense for them to have the reverse box. If the Rangers use the same box, then the Ford box would make a lot of sense from a sustainability perspective.
     
  9. Apr 30, 2011
    jayhawkclint

    jayhawkclint ΜΟΛΩΝ ΛΑΒΕ

    Oklahoma City, USA
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    Had to make another run to the pick-a-part today. The Astro intermediate shaft I picked up when I bought the steering box look pretty close to what I needed, but it turned out to be just 2" too short (about 16" fully extended). After some research, I learned that the 2000-up Astro have a slightly longer intermediate shaft due to a redesign of their column (~14" collapsed, 21" extended). Found one in very good condition for $17. Once home, I found that the end was the same 3/4" x 36 spline that I needed, but it was swedged onto the u-joint. I used a cutoff wheel to go through the u-joint and tip of the splines that were swedged, then popped the remainder of the u-joint off. I slipped my postal u-joint on (pictured at left) with a dab of lock-tite, then once I was sure the length was right, gave it a couple spot welds. If you were doing this project with a GM column, the 2000+ Astro box with intermediate shaft would be a bolt-on affair (just make sure you get the 3-1/2 turn box). If you wanted to use the Postal column but didn't have the u-joint, you would need to cut off the GM u-joint prior to the splines, then purchase a single Borgesen 3/4" 36 spline x double D u-joint to mount at the end of the column.

    [​IMG]

    I think I've achieved my objective here. No cutting or grinding of the engine mounts or crossmember, no complicated shaft angles, PS hoses going to be a straight shot down to the steering box:
    [​IMG]

    Here is the clearance at the engine mount. If I did it over, I would raise the splined end of the steering box by 1/4". When I drilled the mounting plates, I had a different u-joint on there, these were a little bit larger in diameter and come within about 1/16" of the frame mount. I really don't want to hog out the holes to raise it now, will just have to monitor to see if it rubs with frame flex. Took the new F250 shock mount off for the picture, but it also looks to fit in the CJ '72+ aft position without issue. The intermediate shaft is sitting right smack dab in the middle of it's travel at 18":
    [​IMG]

    Now that it's all mocked up, need to take everything back apart to clean up and put on a new coat of tractor enamel before the engine goes in.
     
    Last edited: Apr 30, 2011
  10. May 9, 2011
    jayhawkclint

    jayhawkclint ΜΟΛΩΝ ΛΑΒΕ

    Oklahoma City, USA
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    Well, so much for 3/8" clearance on the manifolds. The Buick 300 maniofolds I'm using stick out similar to the stock Dauntless. I ended up with about 1/8". I didn't feel comfortable, so I ground off some casting flash where the shaft ran, and also made a little notch for the u-joint in the tub, total clearance is back at about 5/16" installed:
    [​IMG]
     
    Last edited: May 10, 2011
  11. May 10, 2011
    Warloch

    Warloch Did you say Flattie??? Staff Member

    Falcon, CO
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    Clint - while it's open to the motor mount, take a little off where the knuckle is close and put a section of tube there (like a 15* slice) to make a nice clean path. It will keep the strength in the motor mount and you should be good with not hitting it that way.
     
  12. Jan 13, 2012
    jayhawkclint

    jayhawkclint ΜΟΛΩΝ ΛΑΒΕ

    Oklahoma City, USA
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    Finished product. Working extremely well:
    [​IMG]

    [​IMG]

    [​IMG]
     
  13. Aug 6, 2012
    jayhawkclint

    jayhawkclint ΜΟΛΩΝ ΛΑΒΕ

    Oklahoma City, USA
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    Post write-up mileage report:

    Been driving this regularly for ~6 months now. Extremely pleased with the way this box handles. The place I notice the most is off road. I used to get a little pucker from time to time with the Ross box when I needed to clutch/gas/shift/steer all at the same time. With the Ross box and especially a Ross box with front locker, steering in a hairy situation often meant two hands required. No longer true. I can easily steer with one hand now, even with a V8 turning a front Detroit locker. This is the second best mod I have ever done to the JEEP, right behind power disc brakes.

    Down the highway the 3-3/4 turn box performs flawlessly. I set my tires to 1/8" toe-in. I can drive with 1 finger on the wheel, it is that good. Changing lanes is a car-like affair.

    From a maintenance perspective, I was choosy when I picked my parts from what appeared to be an otherwise immaculate Astrovan that had been in a side impact, so I have not had any leaks or sloppiness yet. When the day does come, though, it simply is not the "crammed engine compartment" that would be of any concern, and that's with a V8 installed - Dauntless owners are going to have zero concerns with accessing the box. As you can see above, the pump mounts relatively high, about in the same plane as my brake master cylinder, so that the hose fittings are easily accessible. The hoses are a straight shot down to the steering box, and the steering box fittings are easily accessible through the fender cutout. There is nothing there that would require any other component to be removed first if a trail side repair was necessary.

    From a strength perspective, I don't have any measured data, but my "seat of the pants" feel indicates that mounting to the factory boxed section, which is significantly aft of the frame horns (less leverage against the frame), produces no visible or felt flex to the frame. I anticipate that over time the frame stress is going to be less than that of a forward mounted Saginaw box. I have seen just a handful of ECJ5 with front power steering conversions, and of the relatively small number of data points I had to sample, two had cracks developing on the frame horns wherever the owner's added reinforcement had stopped. Heck, I've even seen factory boxes in later CJ develop the same problem. I'm not saying every forward setup is susceptible to that problem, I just think that for my JEEP, I decided mounting to the factory boxed section was right for me.

    From an aesthetic viewpoint, with the hood closed the JEEP appears vintage and the casual observer doesn't even notice there is a box installed. Experienced ECJ5'ers would first notice the bell crank missing. Underneath, the pitman arm comes into view, and you notice the one piece tie-rod. Once you pop the hood, it looks like it could be a factory option it fits so well with the rest of the engine compartment.

    The only thing I would do different is order a spud shaft from McRuff and reuse the stock column. The postal column sits slightly lower than the stock column. It's not an issue for me, but if you have either thick seat bottoms, taller seat risers, or are just a "corn fed" guy, it could be an issue. Using McRuff's spud shaft will allow you to retain stock column height. Or, if you were not concerned about vintage looks, a GM tilt column would allow a driver of any stature to jump in.

    This is when I first finished the swap:
    [​IMG]

    This is the bracket I made. Two pieces of 1/4" plate sandwiching the frame, sleeved through the middle, which is all sandwiched by the GM 3-bolt adapter on the inside and grade 8 washers on the outside:
    [​IMG]

    Sorry it's dirty; I've been trail riding. This shows the mounting location relative to the engine mounts. The engine is a Buick V8, so the Dauntless would give you another cylinder's worth of clearance aft:
    [​IMG]

    This is shows relative position of drag link and tie rod. Even though I later cut out and replaced the front crossmember, that was done to accommodate the larger radiator, not due to the Saginaw swap. For your reference, the box is in exactly the location I first mounted it with the factory cross-member. Again, sorry for the dirty pic:
    [​IMG]
     
    Last edited: Aug 13, 2012
  14. Aug 6, 2012
    wheelie

    wheelie beeg dummy 2024 Sponsor 2023 Sponsor

    York, PA
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    Nice work. I like it all. Nice and clean. Good show.
     
  15. Aug 7, 2012
    AKCJ

    AKCJ Active Member

    Fairbanks, Alaska
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    Thanks for posting. Great stuff!
     
  16. Aug 7, 2012
    Daryl

    Daryl Sponsor

    Bonney Lake, WA
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    Very nice to see someone trying something new. I go through the local pull-a-part looking at all kinds of rigs to see if I can use new parts for old Jeeps. This really does look like you can reduce frame flex and front end wobbles.
     
  17. Aug 7, 2012
    nickmil

    nickmil In mothballs.

    Happy Valley, OR
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    Nice innovation Clint! Looks like a nice setup with your different grill, the V-8 swap, and shock mount change.

    I moved this to fab as it seems to fit better here with the Saginaw steering sticky post at the top.
     
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