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Square u-bolts up front

Blazinaire

1/2 ton status
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Mar 17, 2002
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Santa Maria, CA
After years on hiatus I'm back! With a baby on the way I had better hurry up and finish this thing or it could be another 3 years!

I have been struggling to find room to run a trac bar (panhard bar) on the front of my 87 K5 that is still leaf sprung. The biggest clearance issue is at the axle end (passenger side) where the bar must pass over the u-bolt plate and u-bolts/nuts. If the axle mount was tall enough to clear them, the bar would contact the frame long before I am out of up travel. I was thinking that by running upside down (square) u-bolts that I could be as little as 9/16" or so above the springs as opposed to the 2 1/4" with standard u-bolts. That should buy me ~3" more uptravel as it cycles being that the pivot point is so close to the u-bolt.

The new square u-bolts would drop down through sleeves welded to the boxed section of my axle truss , so they would not require a lower spring plate and all the hardware would be above the bottom of the housing out of harms way.

My question is: is it necessary to run the top spring plate with this setup or can I get away with the center pin only being located on the perch:doah:? If the top plate is necessary are there any downsides to having it wrap down the sides of the spring and engage the u-bolts vertically instead of horizontally? (u-bolts would have to be wider but they could still remain against the top of the spring pack without the added height of the plate.) I know it's kinda hard to visualize but think of a deep piece of channel open side down that is longer (front to back) on the sides than it is on top. That piece would be notched on the sides to locate the u-bolts and have the center pin hole drilled in the top.
 
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One more detail to add is that I cannot mount the bar directly to the top of the u bolt plate as it would make the trac bar shorter than my draglink (creating bumpsteer), or if made equal length the frame mount would stick out too far and get into my sidewall when twisted. So for now that is out of the question.
 
The center pin is only there to hold the spring pack together and to align the axle with the springs, it has no structural value so don't worry about that.

If you cut the u-bolts at the top of the nut the whole plate/bolt/nut combo should only stick up an inch or an inch and half or so I think, is that a possibility?
 
The factory plate along with washer and nut (on mine) stand at 2" so there is not really much to gain by cutting 1/4" of threads off. I realize that the center pin only exists in order to align the spring pack and locate the spring pack to the axle, but is it any more/less effective at doing so by having it engage on one side (single shear, no top plate) versus both sides (double shear, use a top plate) of the pack? Does the center pin even make contact with the top u-bolt plate in a factory stock configuration or does it just fall where it may inside of a hole that is too big?
 
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