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Greg
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43 Posts
Discussion Starter #1
I have looked at alot of builds and alot of threads. and I may be off in left field about this, but i am having trouble completing my SAS build on my 2005 chevy silverado 1550 Z71.

I have a dana 60 HP ford king pin front axle with leaf springs and a kit from 4wdFactory. running 47" leafs from Pro-comp.

(3" drop brackets and 6" springs)

I am running 5*-6* front caster and WFO Concepts cross over steering.

The frame is boxed where the steering box is.. However is have a bear of a time driving the truck down the road. I has wicked understeer or "lag" and i have to correct it all the time. I am running Springless arm and cap. and is set to 20-25 ft lbs.

the truck turns smoothly both running and not on jack stands. I have checked and re-checked the joints and the center position of the steering box and pitman arm. Dop i need hydo assist or something to correct this?




Also I am wondering what people are doing for driveshafts and mods..I see people are bolting in shafts but my setup is requiring alot of modification. I have already cut and modified the crossmember and I need a custom shaft it looks like. however i do not see people doing that..

a stock shaft just doesnt work. not to mention shaft angles suck in the front. requiring a cv. How are people dealing withe angles and the crossmember?

thanks
 

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DeepSouth Gangster
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5,669 Posts
Find a factory late model front shaft for a 1/2ton straight axle truck (pre-'88) that had had a 700r4 and NP208, they were the longest factory front shafts offered in the GM products; giving you enough shaft to shorten a little bit. If you grind the angle stops on the CV it will provide you with plenty of angle. If you can't find that particular shaft, a rear two piece shaft from a 2nd gen 2wd S10 will let you build what you want. The flange on the pinion will bolt to the NP241 you have (given you have a flange output and not a yoke), the male spline will fit all sorts of slip yoke female splines ('88-'98 IFS front slip yokes, '73-'87 front slip yokes, etc.). You disconnect the two piece shaft at the carrier bearing and (if I remember correctly) cut off the male slip spline (should be on the transmission side of the carrier bearing) and clean off the tube and prepare for welding. Once you get your compressed length calculated/measured, figure where you need to make your cut on the rear portion of the two piece shaft. Mark, cut, tack the male slip spline you just cleaned up and install the female slip shaft/yoke to make sure it is the correct length. I have made multiple front driveshafts using the S10 rear shaft. Most can be had at the pik-a-pull for <$40.

As far as your steering, hydro assist will help TONS. I didn't used to be a trac bar advocate, but now that I took my hydro assist off I have become one (although I still have not built a trac bar for my truck yet). When I took my hydro assist off the truck seemed to wonder a lot, and when stopped I can turn the wheel and watch the body shift a little bit before the wheels turn. Poke your head out the window while stopped and see if the body is shifting before the wheels turn. If so, a trac bar (panhard rod) will be a nice solution. A lot of factors go into the need for a trac bar. Some people can get away without it. But various shackle angles and soft bushings contribute greatly to axle shift before the tires turn.
 

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Greg
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43 Posts
Discussion Starter #3
awesome information!!!

i had a 241 front shaft that didnt quite cut it (not enough angle and jusst at its limit for length at my stopped ride height.. so maybe a 208 shaft will work better or arent they the same?

which would you recommend more..the hydo assist or the track/ panhard bar?

i have been contemplating having my steering box drilled and tapped but it would be my first one and i dont know anyone whos done it, at least not on that box.. so id want to get it right and not screw up a perfectly good box..

the truck does flex a little bit. I cant turn the tires at a stop (even though you really shouldn't). theres just not enough strength to turn the 35's at a stand still.
 

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DeepSouth Gangster
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5,669 Posts
Factory NP241 shafts (except the '90-'91 4wd Blazers and Suburbans) were all single cardon joint driveshafts. The NP208 shafts will be single cardon joint at the pinion and dual cardon (CV) at the transfer case.

As far as assist or tracbar is concerned, how tall is the vehicle? It may benefit from both. As far as drilling and tapping, I can only presume it is still a standard Saginaw steering box. Check my SAS thread for pictures and documentation for drilling/tapping a Saginaw box.
 

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Greg
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43 Posts
Discussion Starter #5
as far as i know its some Delphi box.. it does not have an end cap....

the truck has 9" of lift ( apparently according to Rough Country that an equivalent to 16" of IFS lift---center of wheel to fender is 36")

truck sits at 7 foot tall at the roof line



2014050695155746_zps6019342d.gif



20140506_155712_zps1ded61b8.gif



here is an under angle shot:

20140712_124705_zps3f484239.gif
 

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Greg
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43 Posts
Discussion Starter #6
i honestly have so many issues im running into that i dont see anyone else running into...

is it just the year of my truck (2005)?

it also cant figure out how to shift right either now that its been sas'd
 

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New Member
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4,725 Posts
Your drag link may be rotating...
Is your caster set 5 degrees nose up? Symptoms sounds like not enough caster. If you regear ed, you need to reprogram the pcm for it to shift correctly.

Are those drum brakes up front?
 

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Greg
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43 Posts
Discussion Starter #8
They are factory disk brakes. they just have large backing plates

I have reprogrammed the pcm for the 4.10 gears

How do i stop the rotation of the Drag link? i went on the suggestion of Trevor at WFO on the bent drag link

the pinion is actually angled down..so the diff cover is slightly angled up

edit: I have wired in th VSS on the tailshaft of the NP241
 

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DeepSouth Gangster
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5,669 Posts
PM BGGRNCHVY about where to drill and tap a GMT800 steering box for hydro assist. He has done a few I believe. And then relay that information back here so more people can learn.

Your truck will benefit from both, trac bar and hydro assist; trac bar being more beneficial in my opinion.
 

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Greg
Joined
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43 Posts
Discussion Starter #10
for the track bar, a buddy of mine and myself have some discrepencies about where and how they should be done.

Im thinking, longer rod=better and that it should be mounted to the tube and to the frame....He says shorter is better, with mounting to the pumpkin and to the fram

although even with my lift i dont think i have enough clearance for the pumpkin mount (oil pan clearance Clarance)

its hard not to want hydro assist, since it (how i see it) will absorb and bump steer, and basically force the tires to slow down...maybe im looking at it wrong.

i am kind of averting from doing a track bar (even though i know it may be necessary) --because id hate to weld to a painted and clear coated housing and the fact that i dont own a welder

i can get away (for the large majority) with a hydo mount diff cover and a clamp on tie rod mount to simplify things ( i can bring the clamp to a welding shop)

edit: i will try to message him today
 

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Greg
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43 Posts
Discussion Starter #11
note:

I sent an email to WFO to see what they say about the twisting drag link
 

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DeepSouth Gangster
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5,669 Posts
Your buddy is incorrect in this application (lowered cars/trucks can get away with it like that). The trac bar should mimic the draglink as much as possible. It needs to be close in length and mounted in a way so they both travel in the same arc throughout the suspension movement. Next time yall are hanging out at Burger King grab some extra straws and have one as the draglink and another the trac bar (try one short and one long). Keep one end fixed on one point (the corner of a napkin) and pivot it around as the suspension would travel. See which arcs travel similarly.

As far as assist absorbing bump steer, not really. It is an active steering stabilizer (it actively assists steering hydraulically at the same time it (since fluids do not compress) keeps the wheels from wondering when they shouldn't). Highway "feedback" through the steering system is what you are thinking about. You will still get bump steer without a trac bar, leaf springs move the axle on a different axis throughout the suspension travel than the draglink; the trac bar just combines the axis(s) to more or less eliminate bump steer.

It will not be the end of the world for a trac bar to be on the ubolt plate, if that is what you have to do. I have done one that way and many kits are this way.
 

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Greg
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43 Posts
Discussion Starter #13
i didnt even think of the u-bolt plate. that may be a stellar idea. since its easy to remove.. not sure its heavy duty enough , -it doubles as my lower dual shock mount..

may have to beef it up quite a but...

i assume they have to be pretty dead next to each other with the same angles and the same length as you said? this is so i can get my measurement right..

though i think i want to go up 2 more inches for tire clearance...so ill have to figure out the angle at that point
 

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Greg
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43 Posts
Discussion Starter #14
I retract my previous statement about the pinion angle.. the pinion is just slightly angled up.

The top of my kingpins are angle toward the back of the truck..so the lower is in front
 

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DeepSouth Gangster
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5,669 Posts
I think within 8" of length and 5* of angle is acceptable. Put a bushing on one end and it will absorb some funny feelings. The trac bar doesn't have to be real firm since the leaf springs are doing 95% of the axle locating, you are just helping keep the axle move in the arc of the draglink with the bar.
 

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NCOR
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8,451 Posts
As I linked in my PM, tap the box on the end and then tap it above the sector shaft towards the front shown in these borrowed images.

http://www.pirate4x4.com/forum/12415934-post10.html

600 GM boxes and 680 Dodge boxes tap the same.

It's painfully easy. Just grease the bits and tap, flush the fluid out by twisting the input shaft and then run a piece of ER70S bent at the end into the hole with a neodymium magnet attached to the outside of the wire probing for more flakes.

I was pleased enough with the benefits of hydro assist I put it on my Dodge just to cure some of the wander with the wider tires.

IMG_20140701_202206_006_zps158b57ee.jpg
 

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Greg
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43 Posts
Discussion Starter #18
Thanks man...

did you rebuild the box while you had it apart?
 

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GMFS Enforcer
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3,568 Posts
What size tires do you have? As of now, does your steering return to center? I would be willing bet that more caster would help you. Also, any reason the truck is so high? Do you plan to install taller tires? How are your front shackle angles??
 

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Greg
Joined
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43 Posts
Discussion Starter #20
What size tires do you have? As of now, does your steering return to center? I would be willing bet that more caster would help you. Also, any reason the truck is so high? Do you plan to install taller tires? How are your front shackle angles??


My tires are currently 35 x 12.5... I want to run 42's.. my steering does return to center.

You want me to tilt my axle back more? (Pinion toward the ground)

My shackle angles are straight up and down.. I have pro-comp springs in the front.. i had thought this was part of the issue . My shackles were mounted for a 47" spring. With weight on my current springs the measure 46.25" .. i was thinking of switching to super lift springs..

I wrote pro-comp because one side spring required a zero rate to make it level ( seems like far different spring rates)(zero rate is on the driver side).. without custom spring.. i could not find anyone with a 49" spring.... i cant run 52's because my shackle doeant travel that far. On top of that the way they made the bracket: it entraps the bolt so i cant get at it
 
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