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Axle wrap control questions

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by BadDog, Aug 3, 2002.

  1. BadDog

    BadDog SOL Staff Member Super Moderator Author

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    As some of you know, I've been experimenting with a new hybrid rear suspension. In review, I've got F150 rear springs turned backward so the long side (originally the rear) is in front. For the rear (shackle) attachment, I have a modified Springer swing arm setup. Problem is, this is very likely to cause substantial axle wrap. I've been kicking around axle wrap control setups and I can't come up with anything I really like. Here are a few examples and the problems I see. I would love some feedback and fresh ideas. /forums/images/icons/tongue.gif

    1) Marv had a pretty good idea for putting a shock mounted to the top of my differential housing and running forward to a mount hanging from a new cross member. If the axle wanted to twist, it would have to compress or extend the shock. My problem here is that I'm planning to use a 23 gal K5 gas tank which is already going to be too close for comfort to the differential on hard compression (I'll likely make a bump stop on the front tank support just for piece of mind). Also, attaching to the differential is a bit complicated without buying an Avalanche style rock ring with top tab. I'm not crazy about welding to the differential housing. And making a sort of saddle mount that attaches to the pinion support plate (and maybe the cover bolts too) would be complicated build and would also complicate maintenance.

    2) Build a sort of reverse ladder bar type setup with the ladder bar above the axle rather than below. This isn’t too complicated to build but it does have problems. Basically you have a rigid arm welded (or otherwise fixed) to the axle and running forward. Just behind the front spring hanger you mount a shackle. In order for the axle to twist, the forward end of the arm would need to move up and down when the axle rotates. The shackle would prevent that movement without hampering (much) the axle’s ability to move up and down. Ideally the front shackle is mounted near the tcase output so that the pinion is kept oriented (more-or-less) correctly to the output. This system generally will have some bind because it forces that pinion to a specific angle when the spring might prefer it be oriented a bit differently, but it’s not much and the benefit of keeping the pinion angle located relative to the output can’t be overlooked. Anyway, one problem here is that the emergency brake lines are in the way on the driver’s side. These are the funky split lines of a 1 ton and they are not that easy to relocate. I was thinking of splitting them to work separately and that would take care of this issue. The other is that the forward shackles will have to be behind the spring hangers on the frame. This is not the ideal location (for angle relative to tcase output) AND they will hang down at the perfect location to get hung up (about 10” in front of the rear tires). This is my most likely course, and I’m thinking I can build them primarily out of 1” x 0.125 tube I have on hand (if I can locate them where they are relatively safe from rocks).

    3) I’ve also been kicking around some fairly elaborate cantilever stile setups where I could also mount my shocks and extend their travel while reducing the rate. Anyone got some good ideas or pics of setups like this?

    Anyway, pics or descriptions of various rear axle anti-wrap setups would be much appreciated. My head hurts from thinking too much!!! /forums/images/icons/crazy.gif
     
  2. NITRO

    NITRO 1/2 ton status

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    wouldnt it just b easier to put on a shckle flip and call it good /forums/images/icons/tongue.gif /forums/images/icons/grin.gif

    NITRO
     
  3. Blazinaire

    Blazinaire 1/2 ton status

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    The springer setup actually does flip the shackle, it is almost like using 2 shackles on one end of the spring. (like a revolver but IMO safer and stronger) I believe that his problem is because the much softer spring rate of the ford 57'' and longer side of the spring being in front of the axle. I dunno if these would work with a lot of travel, but the idea seems to me (I'm no expert) like it would be effective in controlling axle wrap without too much limitation of wheel travel: www.jcwhitney.com/product.jhtml?catid=81024&bq=jcw2&_requestid=81945 superlift also makes pretty much the same thing.
     
  4. BorregoK5

    BorregoK5 1/2 ton status

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    Your ladder bar setup with the floating shackle is a good idea, I'm making one myself to solve what little axle wrap I have with the 57" springs run normally. I was planning on running mine in the center of the axle just off to the passenger side though. When I power brake, my drivers side rises with the torque leaving the passenger side low, so the ladder would in effect push the passenger side up a little to help it rise a little flatter. Having it near the center helps prevent the bind a little under full articulation and could also be fabbed with a driveline sheild off to one side to keep rocks off it as an added benefit. Just my thoughts, I imagine you'll get all kinds of good ideas off your post. Now explain the cantelever design a bit more if you would!
     

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