Initial torsion bar settings...

Good morning,
I dorked around with my torsion bars trying to level out the ride (side to side), and I can't quite get the feel I want. I may have got lost in the adjustments.
Is there a procedure out there on how to initially preload the t-bars and set Z-height?
The truck is a '04 Silverado SS - but I'm willing to hear anything on any full size GM chassis.
I also want to note that from the factory, the drivers side adjuster was a good 3/8" further out, than the passenger side. The bump stop was also kinked in it's little cup, which made it sort of slip off to the side on the lower control arm. I fixed that, and it feels like the drivers front is MUCH stiffer than the passenger side.... like I need to pull even MORE of the adjuster bolt out.
Does this sound right?
Bringing it to the dealer is a last resort for me.
Thanks, -marc
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"Marc Westerlind" wrote

Since you fiddled around with the torsion bars, you might just as well take it into a shop and have them set the z-height for you and perform an alignment. You can't just adjust the torsion bars up and down without doing an alignment. The ride height must be done before an alignment, because changes in ride height will affect the alignment.
z-height is 4.3-4.8" on your truck, but I can't really explain where the measurement is taken....you really need to see the diagram that is in the service manual.
Ian
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shiden_kai wrote:

That's what I'm really considering right now...
I'm just nervous that they'll set it to something that looks good parked, but rides poorly. That's kind of what I'm trying to tune out now. The truck seems to favor leaning to one side over the other, once out on the road. It doesn't follow the camber of the road properly.
I initially started off with a half turn tweak on the driver side to bring it back up. (that side was sagging) Then it snowballed from there...

Thanks - that's good... I have a diagram at home that I got from the dealer, who pulled it off of some official locked down GM service tech site a while back.
It says to measure the height difference from something like the lower control arm pivot, to the centerline of the lower ball joint - or something like that. I don't have it in front of me.
I'm going to have a real hard time getting to the dealer during their service hours, so I was hoping I can fudge it for a few weeks. A half inch difference in Z-height is a bit too much to fudge though...
Thanks again, -marc
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"Marc Westerlind" wrote

Are you saying here that the truck "pulls" to one side? I was under the impression that you were simply concerned with the truck leaning to one side when it's just sitting still. If you are instead talking about "pulling" while you are driving down the road....tweaking the torsion bars is the wrong way to adjust for a "pull". It is possible by a stroke of luck to be able to compensate for the pull by fiddling with the ride height...but it would just be pure luck.
> I initially started off with a half turn tweak on the

Ahhhh...here you are saying that you were compensating for "sag". Probably what has happened is that you have changed the caster/camber enough to cause the truck to wander to one side.

Yes, frankly it's not a particularly easy measurement to make...since there is 1/2" allowable variance, I usually just concentrated on getting the ride height equal from side to side. You could just measure from the frame to the ground and make sure that the truck is even at that point.
After all is said and done....you still need an alignment.
Ian
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shiden_kai wrote:

No, it's weird. Parked, it looks pretty good. There's maybe a SLIGHT difference in ride height from side to side.
The truck doesn't really pull on me at all. When it sags to one side, I usually have to crank the wheel slightly to the other side to compensate. That's it.
Out on the road, it seems to favor leaning to one side over the other though. I can't tweak either torsion bar to get the truck to actually ride as level as it should.
One day it likes this side... after tightening that side, or loosening the other, it flops to the other side. I can't find an equalibrium.
I followed a 1500 Chevy, and a Tahoe this morning - they both rode nice and level looking, while mine seemed to dip excessively, or carry a weird posture for an extended amount of time.

Gotcha.
One more question I suppose - is it necessary to disconnect the sway bar when trying to level things out when the truck is parked?
I'm not certain, but I 'believe' the SS has a larger/tighter sway bar up front, which I suppose would dampen side to side torsion bar adjutments slightly.
Thanks for all the help, -marc
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"Marc Westerlind" wrote

No, it's not necessary to do anything related to the stabilizer bar when adjusting the torsion bars or performing an alignment.
Ian
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shiden_kai wrote:

Thanks for all the help, Ian, I appreciate it.
One FINAL question - what should I expect to pay for the Z-height and alignment work?
I just got off the phone with a local dealer, and totally forgot to ask. I mentioned that I'll probably hang out at the shop (need a ride), and he said it'll be up on the rack for about 2 hours. That's a little longer than I thought.
I feel like a dumbass calling back and asking. At least on here, it's rather anonymous. ;)
-marc
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shiden_kai wrote:

Well, I have to admit that the local dealers service came full circle.
They did the Z-height and an alignment all under waranty.
Last experience I had there was in '99, when they said it was normal for my S10's pedal to hit the floor when I braked hard. (DOH...)
The truck rides great.
-marc
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