torsion bar/lower control arm Z height issue

[Justin35594]

I've been experiencing a issue involving height related to torsion bars on my 1999 GMC Sierra. I am having trouble determining if it is the driver side torsion bar, or perhaps the driver side lower control arm being worn where the torsion bars sits in it. This issue is non-existent on the passenger side. On the driver side, I removed the torsion bar for some other work I was doing and when I re-installed it in the lower control arm, I noticed the keys were positioned differently literally every way I turned the bar or tilted the lower control arm on the driver side. The keys are the same but on the driver side the torsion key seems to sit lower than the passenger side when installing it making the driver side higher which in turn makes the lower control arm sit lower. This is causing far too much camber on the driver side making turn radius on that side a little sketchy. It is also making my lower control arm make contact with the steering knuckle. The ball joints are all new. Could this be a worn lower control arm, or possibly the torsion bar on the driver side alone? Is there a fix to correct the issue? If anyone has experienced this or can make better sense of it please let me know!

[dna9656]

I have been in vehicle maint. for a LOT of years and never had I heard of a torsion bar getting weak, I'm sure it can happen, I've just never heard of it. I would replace all the control arm bushings with silicone rubber ones and go from there. Replacing them all will give you equality on both sides so you can better measure the fender height (top of the opening of the fender well) to find and determine the vehicle's side to side level.

Edited October 23, 2021 by dna9656
typo

[Justin35594]

Thank you. I appreciate the advice.

[dna9656]

Also, make sure your control arms or correct, straight /not bent. They might be the wrong ones! I mean you bought this used right? Stranger things have happened!

[Justin35594]

Yea there definitely was some sketchy crap on it when I bought it last July. I'm likely just going to do a coil over conversion and removed the bar set-up. This truck is a good working 4x4 but is also tuned and cam swapped so I figure that would be an upgrade for suspension and certainly some sort of weight reduction because them bars weigh a ****** ton. I tune using that HP tuner program with the MVPI2 and ****** awesome. This issue has just been messing my alignment up making handling crap since I first looked into the problem. 

[dna9656]

IMHO unless you're an engineer or you have properly engineered parts changing what the original designers had in mind can quickly turn into a slippery slope of broken parts and unnecessary expense. I think torsion bar suspensions are more expensive and stronger than coli over shock (McPherson strut(?) set up that's fine for most on road applications.

So, can I assume you want to reduce weight for mileage?

Will you be putting HUGE wheels and tires on the truck later (there goes your weight reduction) along with other parts?

It's your truck of course but I do know that the chevy pick ups (M-1009 CUCV) the US military bought were rated at 1.25 ton pay load weren't raised up, use huge tires, or had coli over shock front ends, they had a conventional (old school ) solid front axle more MFRs have abandoned for expense and weight considerations.

[Justin35594]

No, I do not intend on weight reduction. As I mentioned above, I plan to convert it to coil overs to ensure the height issue is corrected which is affecting my alignment on the drivers side. The camber is too excessive because the torsion bar and key position is different from the passenger side no matter which way the bar is oriented. This causes the lower control arm on the drivers side to be much lower which means ride height will be greater on the drivers side. Like you said though, it's probably something with the bushing. this issue could be occurring with loading and unloading. The bushing may be binding but I haven't verified yet.