Torsion bars?

[Twithers]

I'm new to my Tahoe, so I'm not sure if I'm getting the terminology right, so bear with me and correct as necessary.

I noticed that the passenger's side front corner was lower than the driver's side. I thought maybe it had some accident damage, but when I got under the truck, I noticed that there are 2 bars running aft from the front to about under the 2nd row seats. At the end of the bars is a teardrop shaped plate, with a bolt running vertically, and the head of the bolt facing the ground. The passenger's side bolt was run out much farther than the other. It had a little over an inch of threads showing and the driver's side bolt had about a 1/4" of threads showing. I jacked up the truck, so the passenger's front tire was off the ground and then drove the corresponding bolt to roughly the same spot as the other one. After I let the truck down, the front seemed to be pretty level. So, I'm guessing these are the torsion bars, but correct me if I'm wrong. On the test drive, I noticed that the truck didn't pull at all, but the steering wheel is a few degrees off center. If I let go of the steering wheel and let it center out, the truck doesn't pull to either side, but the steering wheel isn't perfectly centered. I'm not sure if it was this way before and I just didn't notice or if it has something to do with the adjustment I made. Also, the spacing between the front fenders and the top of the tires seems a bit much, like the front end is a little high, but I don't actually know what it's supposed to be.

So here are my questions:
-Is that the right way to make the adjustment, lifting the corresponding front tire off the ground, adjust the bolt and let the truck down?
-Is there some way to make an accurate measurement to know that both sides are exactly the same? Fender to the top of the tire doesn't seem very accurate, with fender fitment and tire tread being variable. There should be some other part of the truck to measure with that's consistently accurate for both sides.
-Once the proper measuring points are determined, what exactly should that measurement be, considering that everything is stock, including tire size.
-Is the steering wheel being off center because the adjustment between the 2 sides isn't perfectly equal, or does it have to be something unrelated?

Thanks for the help.

 

[wjburken]

Yep-you adjusted the torsion bars. The teardrop piece is called the key. Sounds like you adjusted it properly by taking the weight off.

If you are at the mid range of the jack bolt in the key, you should be within a good range. People crank these up and down to adjust rose height often.

A good place to measure is top of fender to center of hub and make sure they’d re the same on both sides.

Might want to get it in for an alignment. Hopefully the shop will naturally center the steering wheel.

 

[Twithers]

"Jack boat in the key", what's that?

"Top of the fender", where exactly do you mean? Where the fender meets the hood? What would be a normal measurement for a stock setup?

Thanks.

 

[wjburken]

"Jack boat in the key", what's that?

"Top of the fender", where exactly do you mean? Where the fender meets the hood? What would be a normal measurement for a stock setup?

Thanks.

I had a typo. I meant Jack Bolt in the Key. This is the bolt you adjusted to adjust the height of the side of your truck.

Top of fender would be the top of the fender opening above the center of the wheel.

Can’t answer your question about an exact stock height, but the front is typically 1” or so lower than the rear wheels from the factory. This 1” difference between the front and the rear os the rake of the vehicle. Many people will adjust their torsion bars so the front and rear heights are equal.

 

[Twithers]

Ok, that makes sense.

Thanks.

 

[iamdub]

I'm new to my Tahoe, so I'm not sure if I'm getting the terminology right, so bear with me and correct as necessary.

I noticed that the passenger's side front corner was lower than the driver's side. I thought maybe it had some accident damage, but when I got under the truck, I noticed that there are 2 bars running aft from the front to about under the 2nd row seats. At the end of the bars is a teardrop shaped plate, with a bolt running vertically, and the head of the bolt facing the ground. The passenger's side bolt was run out much farther than the other. It had a little over an inch of threads showing and the driver's side bolt had about a 1/4" of threads showing. I jacked up the truck, so the passenger's front tire was off the ground and then drove the corresponding bolt to roughly the same spot as the other one. After I let the truck down, the front seemed to be pretty level. So, I'm guessing these are the torsion bars, but correct me if I'm wrong. On the test drive, I noticed that the truck didn't pull at all, but the steering wheel is a few degrees off center. If I let go of the steering wheel and let it center out, the truck doesn't pull to either side, but the steering wheel isn't perfectly centered. I'm not sure if it was this way before and I just didn't notice or if it has something to do with the adjustment I made. Also, the spacing between the front fenders and the top of the tires seems a bit much, like the front end is a little high, but I don't actually know what it's supposed to be.

So here are my questions:
-Is that the right way to make the adjustment, lifting the corresponding front tire off the ground, adjust the bolt and let the truck down?
-Is there some way to make an accurate measurement to know that both sides are exactly the same? Fender to the top of the tire doesn't seem very accurate, with fender fitment and tire tread being variable. There should be some other part of the truck to measure with that's consistently accurate for both sides.
-Once the proper measuring points are determined, what exactly should that measurement be, considering that everything is stock, including tire size.
-Is the steering wheel being off center because the adjustment between the 2 sides isn't perfectly equal, or does it have to be something unrelated?

Thanks for the help.

Ever heard of the "Chevy Lean"? It's the left side of GM trucks being noticeably lower than the right side due to the extra weight of the steering and controls systems, fuel tank and driver. Perhaps the previous owner was a rather "voluptuous" person and they had the left side adjusted up to fix the lean plus a little more to account for their weight, then had it aligned at that height.

I'd recommend getting a professional alignment. If your alignment was great before and the tires were wearing evenly, you might be fine with adjusting the tie rods to center the wheel. Whichever way the wheel is turned, you wanna adjust the rods that same way. For example, if the wheel is turned to the right, you adjust the rods to turn the wheels as if they were making a right turn. Turn the adjuster one half to one full turn and be as precise as possible. However much you turn one, turn the other the exact same. Again, be mindful that you are extending or shortening the correct side tie rod as needed. Tighten the adjusters, test and readjust as necessary.

The most accurate way to measure corner height is from the bottom of the fender, directly over the vertical center line of the wheel, down to either the top wheel lip, center of the hub (wheel centercap) or to the bottom of the wheel lip. You don't go from fender to ground since this can be skewed by tire. You also have to roll it forward or back after lower it back down off the jack so it's settled. Ideally, you'd go for a short drive up and down the street or around the block, bonus points if there are speed bumps or rough roads to ensure the suspension is settled.

To get an idea of where they should be set from the factory, you'd first need the jounce stops to be in good condition. These are the foam, originally yellow bump stop-looking things on the frame right above a circular pad on the control arm. At ride/resting height, they should be just a hair away from touching the pad or lightly pressed onto it. If they're old and squished, and with yours being lifted, there's bound to be a decent gap between them. Replace 'em and see how it sits and rides.


Measuring points-

Fender to hub/wheel center:





Fender to lower lip, through center line ("A" in this example):




Jounce bumpers:

 

[Twithers]

Are there jounce bumpers in the rear also? I don't remember what the front ones look like, but I do remember seeing something like those on the rear and they looked old and dry-rotted. I didn't think much of replacing them, because I thought they were only there in case you hit a bump so hard that it bottomed out. I would assume if they are the same thing on the rear as they are on the front, and the rear ones looked that bad, I should just replace all of them.

Thanks for the detailed explanation of everything. It definitely helped.

 

[Twithers]

Oh, and.....

Rather than adjusting the torsion bars so that the front fender measurements are 1" lower than the rear fender measurements, do I need to wait until I replace all the jounce bumpers and then adjust the torsion bars until the bumpers rest on the control arms?

 

[tRidiot]

I watched this the other day and thought it looked like a pretty doable thing for most folks.

 

[iamdub]

Are there jounce bumpers in the rear also? I don't remember what the front ones look like, but I do remember seeing something like those on the rear and they looked old and dry-rotted. I didn't think much of replacing them, because I thought they were only there in case you hit a bump so hard that it bottomed out. I would assume if they are the same thing on the rear as they are on the front, and the rear ones looked that bad, I should just replace all of them.

Thanks for the detailed explanation of everything. It definitely helped.

The ones in the rear are bump stops. They're very similar to the ones in the front in appearance. The difference is the front ones are to supplement the springs. They are constantly under load and squish along with the cycling of the suspension. The rears are to give a soft impact when limiting maximum upward travel of the rear axle.