Caster probs with susp. lift?

[xterrabull]

Well I searched the relevant boards & came up with nothing....
I just installed SLR UCA's (sans diff drop for now) and went for wheel alignment.
Camber was brought into spec (thank goodness) but caster couldn't be improved beyond -1.7 driver & -1.4 passenger (spec is 1.7 - 2.7 degrees).
I've never heard of this problem before with any of the UCA's out there.
Problems associated with negative caster are livable (no abnormal tire wear but sensistive steering at high speeds, which I have noticed slightly but then again this could be primarily due to the lift itself).
Still, I'd like to try to correct this.
Any ideas out there?

BTW I also installed the Fabtech AAL and the SLR 1" rear shackle IN ADDITION to the Rancho AAL I already had in place. The rake isn't too bad (about the same as the Rancho AAL alone with a 1" T-bar lift).
The ride is good -- the back end with the Rancho RS9000's set to '2' rides only a tad softer than it did set to '3' before the added lift. Also the 9116 in the back limits droop but I think the 9112 will fix this (9112 is 1.15" longer compressed & 2.25" longer extended -- I don't know if longer compressed length will prevent full tuck -- something to look into).
One more item:
Is there anybody out there who has actually removed the stock diff-mount bushings without the use of a press? Right now I'm thinking of attempting a combined drill/roto-zip/torch approach but I'm wondering if this would lead to merely a 1/2 day job or more like a full weekend of blood/sweat/tears/regret....

Any feedback is mightily appreciated; also I'll do some measurements if anyone's specifically interested...

[xoc]

Don't "stack" add-a-leaves, especially from different manufacturers.

Take the diff to a shop, it will save you a lot of time and anger.

[aero_steve]

I had the diff drop installed by a truck customizer around the corner from where I work. It took them about 4 hours to deal with it. SLR didn't ship the press tool for the small bushing and getting it back together took a while. I don't think they realized what a PIA it is. Better their aggravation than mine.

Caster and camber are adjusted by the same bolts, so it ends up being a trade off to get the alignment. You may need to increase the camber to get the caster in better. Also I had to have the torsion bars cranked up to about 1/4" gap to get the alignment barely within Spencer's specs.

The SLR torsion bars have settled about 2" total since installing. I've had to crank them up a little each month since installing. I measured Tuesday and the gap at the bumpstops is 1.25", so there is no chance that an alignment will work. I have SLR's spring pack and it has settled with the torsion bars. Right now the truck is close the level. The rear of my rock sliders are a 1/4" higher than the front. No noticeable rake. If I crank the torsion bars back up for an alignment truck will be nose high. I sent an email a couple days ago to SLR to ask for suggestions and am waiting for a response. By the way the lift only has been on for 3 months and 4000 miles

[xterrabull]

Originally posted by xoc
Don't "stack" add-a-leaves, especially from different manufacturers.

This sounds like a good rule of thumb; however, the work is done & I'm very happy with the ride so it might take a little bit more than that to get me under the truck again.
The reason I wanted to add the Fabtech is that the Rancho leaf is so short that it crimped the stock leaf above after a trip to the sand dunes. Plus, knowing that the Rancho leaf gave lift by forcing more arc in the stock spring pack, & that the Fabtech leaf likely worked the same, I figured that adding the Fabtech leaf wouldn't "double-up" the amount of lift -- & this has proven to be true. The Fabtech leaf length is longer than the Rancho but shorter than the stock bottom leaf, and it is not as stout as the Rancho so it seemed to me that it would lead to something approaching a progressive springpack.
I added the SLR 1" shackle to gain some articulation in addition to the lift of the leaves while not causing the problems associated w/a 2" shackle -- basically a compromise between AAL & shackle lift.

As for the alignment, I have 1" spacing from UCA to bumpstop; I just looked at SLR's website & saw their alignment specs for the lift (Why didn't they send them to me with the lift or mention them to me????) & it specifies 3/4" - 1/2" UCA-bumpstop spacing in order to achieve their alignment specs. I'd prefer to not go too aggressive on torsion crank to help in some small way mitigate steering wear.
Also, I have SAW T-bars on for a while now & hopefully they won't settle any more than they already have.
I think I'll live with the caster issue (SLR says -.5 degrees minimum (vs. stock +1.7) so I'm not as far off as I thought) until I upgrade the steering system then try cranking the T-bars some more & see if that helps....

[xoc]

Originally posted by xterrabull
short that it crimped the stock leaf above after a trip to the sand dunes.

Keep an eye on that crimped spring, it can fail now very easily. I would highly recommend replacing it.

SLR used to recommend 3/4" clearance to the bumpstop, and that was before they switched to a lower profile stop.

Their recommendation of 1/2" to 3/4" with the new shorter stop does not make me happy, it lifts the front of the truck way too high.

[xterrabull]

Originally posted by xoc


Keep an eye on that crimped spring, it can fail now very easily. I would highly recommend replacing it.

SLR used to recommend 3/4" clearance to the bumpstop, and that was before they switched to a lower profile stop.

Their recommendation of 1/2" to 3/4" with the new shorter stop does not make me happy, it lifts the front of the truck way too high.

That's gotta be pretty ugly when a leaf spring fails -- thanks for the heads up. When $$$'s are better I'll definitely replace it with a full pack or at least a 2-3 leaf AAL set.
1/2" to 3/4" with a shorter bump stop? That does sound like a bit too much lift (I have the 1" gap with a stock bumpstop).

[Ag_xterra]

i have the exact same setup as you have on your truck. SLR stage 1 with 1" shackle in the rear. Fabtech AAL which i already had then added in a rancho AAL for a slight rake. i've been running this setup for about 3 months now. been wheeling a few times including trails at paragon during ECXC this past weekend. in my opinion the ride is harsh with 2 AAL's stacked and it probably isnt the best way to achieve the lift you want but its my truck.


no alignment problems here. print out the SLR alignment specs from the SLR website and if you cant get them into those specs call SLR and get them to send you another set of upper A arms.

[xterrabull]

Yeah, the ride is probably a bit "too harsh"; but exactly how harsh is too harsh is subjective to an extent.
To help with the stiffness, I dialed down the Rancho's to a softer setting (#2).
It definitely helps to have this freedom, but I *can* feel the stiffness of the springs, manifested primarily as a quick rebound on freeway bumps (this only becomes really annoying at speeds >~70 mph).
Are you running Rancho RS9000s in the back?
Someday I'll upgrade the rear springs but until then I'm fairly content...

[Ag_xterra]

no i dont have the ranchos in the rear, i have the extended length bilsteins. they were really harsh and stiff at first but have become liveable now. i'd still rather have the SLR springpack but the funds just aren't there yet, maybe someday.