bump steer after d60 swap

[black dawg]

I recently scrounged a 60 for the front of my suburban, and after putting it in, it has pretty bad bump steer.
It has stock 3 leaf packs, and height wise looks normal, the drag link runs uphill (slighly more than the spring pack) from front to back.

I know that if I added some spring height the problem would go away, I just dont get why with stock height stuff that it is doing this.

 

[454Sub]

Most likely the kingpins are worn out, or the tierod/pitman arm joints.

Or they are all slightly worn out, and amplifying each other.

 

[black dawg]

everything was nice and tight when I put the 60 in the other night, I will check stuff again, when I have a bay open.

 

[454Sub]

A fish scale can be used to check the kingpins, I believe it needs to hit 25lbs on the scale to move the knuckle for it to be correct.

 

[rebelgregory]

I agree with 454Sub.

Also, the uphill draglink....If you're on stock springs (inverted) and your drag link is still uphill, is it possible that the axle has some type of raised steering arm? Or do you have a dropped pitman arm? Seems like it'd be obvious, but it's worth asking.

 

[sweetk30]

25 lbs of pulling/drag force is correct.

and the HUGE beefy spring in the upper cap will never realy let you tell if stuff is work till its way to far past worn out .

time to get in there and check it over .

 

[black dawg]

I agree with 454Sub.

Also, the uphill draglink....If you're on stock springs (inverted) and your drag link is still uphill, is it possible that the axle has some type of raised steering arm? Or do you have a dropped pitman arm? Seems like it'd be obvious, but it's worth asking.

The drag link is only slightly more uphill than the springs, everything is stock.

when I had the tie rods off, it took a decent (no fish scale) amount of force to turn the knuckle, but I will get it in and give it a good check over.

It makes me laugh a little, that I have NO intention of EVER running anymore than 35s on this thing, and currently has 235/85/16s, but I just had to have a 60.

 

[nvrenuf]

Any chance this is a Dodge axle or you have a Dodge steering arm on a GM axle?

 

[black dawg]

Any chance this is a Dodge axle or you have a Dodge steering arm on a GM axle?

how can I tell for sure?

 

[sweetk30]

drag link end drop down in to steering arm = gm style.

drag link end goes up in to steering arm from bottom = dodge.

 

[black dawg]

its a chevy arm

 

[dvdswan]

what's the caster angle sitting at?

 

[black dawg]

what's the caster angle sitting at?

kinda lost this thread... havent measured caster, but I can tell that it needs more.

When I did get to checking it out, I found nothing wrong with the king pins, but the springs that I had left bolted to the d60 were slightly loose on the drivers side.
The u bolts tightened up nicely, and now no more bump steer.