M1009: 4" lift - draglink geometry correction- dropped pitman / raised steering arm?

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McLovin

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M1009: 4" lift - draglink geometry correction- dropped pitman / raised steering arm?

Good morning together,

my M1009 has a 4" leaf springs in the front without any steering components corrections done.

I have installed a dropped pitman (should give theoretically 2" of drop) arm yesterday, to correct a little bit the scaring drag link geometry.
As I have understood, the drag link should follow the arch of the leaf.

So, what do you say, is this acceptable?

drag_link_1024.jpg

Or should i install the original pitman arm back, remove the original steering arm and replace it with a 4" rised one?
If so, will be a 4" correction for a 4" lift not too much?

Thank you.
 

Chaski

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What does it drive like? Looks okay at first glance to me.

Personally I don’t like raised steering arms on knuckles. The taller the steering arm is on the knuckle the more the truck will dive right under hard braking. When you get on the brakes hard the front axle will “wrap” a little bit deflecting the leaf springs as the axle housing itself is trying to rotate forward. The taller the arm is, the more exaggerated the steering deflection to the right will be, as the top of the arm will be further from the center of the axle housing which is rotating slightly forward under hard braking. This gets even worse with larger tires...
 

cucvmule

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Having more experience with K30's than K5's or K10's, I have always used knuckle blocks to keep less stress off the steering box, pitman shaft bearing, and frame rail. I have never used the arm as I see an increase in lever stress with the arm.

I guess it is a matter of preference, once you add lift the stress increases any way, especially with larger tires. The pitman shaft with the altered pitman arm will have an altered sweep. After 6 inches cross over steering is what should be used as it is a safer option.

As long as you do not alter the geometry then the only change will be by adding on weight of the tires and the added turning stress.
 

andyh1956

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I would add that in a perfect world the drag link should sit level at rest to keep bump steer to a minimum. The drag link type of steering linkage will always have SOME bump steer engineered into it though, we do the best we can. Keep them U-Bolts TIGHT!!!
6 degrees or so Positive Castor will help with steering return & also seems to help on ours with the bump steer.
The larger the tire the more Positive Castor they seem to like.
 

McLovin

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Thank you all for the informations.

I will try to conclude:

* use the dropped pitman arm, makes stress to the steering box.
* Use the raised steering arm, makes the bumpsteer worser, because of the axle wrap during brake operations.
* Use crossover, moves the axle left and right during turn operations.

I have never driven my truck, as i have bought it in a not 'drivable' condition, so dont know about its handling.
It has standard axles, 4" springs (48" front and 52" rear) and 37-12.5-16.5 tires.
(Dana 60 and 14B FF with a detroit locker from a M1008 are allready here in my garage, but i'm not sure, if I will need it)

I think, it will be a 'street truck', as we dont have here in Europe any 'offroads', just restore it for my wife :)

The idea was just, as i'm rebuilding the original axles at the moment, to correct a bit the drag link.
I think in my case, i will stay with the original steering arm and dropped pitman arm and see, how it will operate.

Thank you all again.
 

sweetk30

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i have been driving a drop pitman arm on the steering box for years now and no real problems .

as said good mod is the offroad design bolt in steering box brace kit .
 
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