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Discussion Starter #1 (Edited)
takin a break here to ask a question...i am setting up my front axle and have a question about how long a pivot bracket should be...i am using hair pin radius rods, the current bracket that is welded onto the frame is putting the ctr of the pivot bolt about 4" below the frame. this has the rods setting horizontal. i would like to have it a shorter bracket, say by 2", but this will put the hair pins at a slight upword angle towards the rear. is this ok to do?
 

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Not really . You want your bones at a 90 dgree angle to the spring. :) This minimises the tendency of the bones to push or pull the axle as it goes up and down.
 

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Discussion Starter #3
hair pin set up

thanks..i see what you mean as i just read a thread about bump steer...i had heard the term but didnt know what it was..one question..here is what the article said....."The bottom line to this is that it is best with hairpin radius rods to keep the attachment point for the drag link as close to the same center as the radius rod attachment point. If it can't be achieved, keep it as close to the same height from horizontal as possible to minimize bump steer."
my question is...if i use a manual or power rack steering system this would eliminate the drag link attachment point. the rack ends would flex with the axle so, would i still have bump steer? i would think no am i right?
 

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Gotta remember that the location of the pivot point also affects castor as well..Now if with the rack you are using "crosslink" steering that will help a bit with "bump steer"

power or non power will make no difference in bump steer it is all in alignment and the locations of the pivots and such in relationship to each other..

Sam
 

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Discussion Starter #5 (Edited)
if i draw a line from one steering arm end to the other, and mount the steering racks ctr on this line,the racks ends would attach to the right and left steering arms (no cross link) I am thinking that this will work..but keeping the hairpins as close to horizontal as possible so as not to push/pull on the axle as it swings. Am I wrong? any thoughts appreciated..i would love to add pics but dont know how to do this..
 

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Radius Rods, Hairpins

Using Hairpins with clevises at the axle end allows a little more wiggle room than fixed end radius rods when it come to rear attachment point bracket length.
Since the clevises allow you to adjust the axle's caster angle to the 5-9 degrees (assuming it is an early Ford axle setup), you may be able to get that rear bracket tighter to the frame. Just make sure you're not putting the bind to the spring and shackles in the process.
I don't like the full wheel to wheel rack & pinion idea on a straight axle front end. If you mount it to the frame you have a bind/bump steer problem, if to the axle you have a sliding joint shaft to make up...no thanks.
If you can use cross steering to the right front wheel ala 35-38 Fords or in modern term using a Vega box you can buy a goodie called Uni-steer which is essentially half a rack and pinion. Many folks say it works great.
 

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Discussion Starter #7 (Edited)
hairpin setup

hmmm...so what your saying is that the rack that i plan on using wont have a proper arc to match the suspension travel? wouldnt this uni-rack have the same problem then? If the axle moved upwords say, the arc of the uni-rack arm that was connected to the steering arm, moved upwards then inwards in its arc, would thereby pull the steering arm inwards also no? If this is true then any system would act the same. The ones with a greater arc would tend to be better I would think because of less pull on the steering arm..It would seem to be best to mount the rack on the axle (rather than to the frame)to eliminate the rack pulling/pushing the steering arms each time the axle moved up or down. Also by mounting to the axle, providing the length of the steering arms are right for the amount of rack travel so as to get enough steering angle, (that reminds me..anybody have any idea where i can get the length of a dodge omni steering arm?)the only thing i would have to worry about is, bump steer if the hair pins were not mounted correctly. Any body using a push/pull rack on a coupe? problems? ideas ? comments? :confused:
 
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