Alignment done but... I was told it is 1/4 in lower on the left side.

[Tozan]

I recently replaced all 4 control arms and anything else that was loose and put on new tires then took it in for alignment. The alignment guy told me my front and rear left side are 1/4 inch in lower... If you measure to the same points on the body the left is around a half inch higher.

My print out ended up being pretty close to what I wanted except the left caster is only 3.2 and I wanted 4.5 we did get 4.4 on the right side.

So I am thinking new springs in the front both sides maybe I can find a longer spring and something a few pounds heavier too. I would like to lift the front an inch higher and get them the same on both sides of course too.

The rear had both springs replaced when I did the lift kit a couple years ago. I can't imagine why one side would be that much lower from the springs. So maybe it is something else. I guess I will need to remove both springs and measure them to see if that is the problem.

I was also looking at the bump stops on the rear the metal piece is about 4 inches I wonder if I can reduce that and pick up some extra travel? The rubber bumper is around 3 inches long I wonder if I can get away with cutting it in half?

Part of my goal is to get more suspension travel for my off road adventures and to get things leveled side to side....

 

[iamdub]

I recently replaced all 4 control arms and anything else that was loose and put on new tires then took it in for alignment. The alignment guy told me my front and rear left side are 1/4 inch in lower... If you measure to the same points on the body the left is around a half inch higher.

My print out ended up being pretty close to what I wanted except the left caster is only 3.2 and I wanted 4.5 we did get 4.4 on the right side.

So I am thinking new springs in the front both sides maybe I can find a longer spring and something a few pounds heavier too. I would like to lift the front an inch higher and get them the same on both sides of course too.

The rear had both springs replaced when I did the lift kit a couple years ago. I can't imagine why one side would be that much lower from the springs. So maybe it is something else. I guess I will need to remove both springs and measure them to see if that is the problem.

I was also looking at the bump stops on the rear the metal piece is about 4 inches I wonder if I can reduce that and pick up some extra travel? The rubber bumper is around 3 inches long I wonder if I can get away with cutting it in half?

Part of my goal is to get more suspension travel for my off road adventures and to get things leveled side to side....

The springs on the left side sag more over time because the left side is heavier due to the driver and fuel tank. You could swap the springs left-to-right and reassess from there. I don't know how yours is lifted currently, but you could use a spacer to lift it that extra inch you want. Just get one a little larger for the left side to level it.

You can trim off the bump stop and it's bracket from the frame to gain about 5" of travel. This is very common with lowered rigs- look up "free travel mod". I recently did this to mine and I have some pics in my build thread: https://www.tahoeyukonforum.com/threads/growing-up-doesnt-have-to-suck.93510/page-19

 

[Idriveaho]

My driver side sits 1/2 inch lower. Most likely what he said weight of driver and tank.

 

[Tozan]

I wonder what I can do to get my left side castor up to 4.5

 

[kbuskill]

I wonder what I can do to get my left side castor up to 4.5

Is there a reason you want to get both sides up to 4.5???

Wouldn't it be easier to make them both match at 3.2?

 

[swathdiver]

I recently replaced all 4 control arms and anything else that was loose and put on new tires then took it in for alignment. The alignment guy told me my front and rear left side are 1/4 inch in lower...

Check your swaybar bushings, both on the frame and on the end links; up front especially.

 

[Tozan]

Is there a reason you want to get both sides up to 4.5???

Wouldn't it be easier to make them both match at 3.2?

I agree 3.2 would be easier and fine on the street or wont contribute to wear but, 4.5 will help keep it more stable at high speeds on and off road. I have been known to hit 75mph on hilly back roads and twin tracks catching a little air with it... Rancho the lift kit maker recommends
Camber zero and -.3
Caster 4.5 +/- 1
Toe in .1 +/- .2
They got everything but the caster where I wanted it and even the caster is pretty close I think if I get the left side up I might be able to get the numbers a little closer too. Or maybe I will need to get a new adjustable upper control arm.

Check your swaybar bushings, both on the frame and on the end links; up front especially.

James, all of those are new I replaced them when I put the swaybars back on... I am thinking of disconnecting the front sway bar again to free up the front suspension off road. I will check the height again after I do the disconnect. Without the sway bar having a little extra caster should be a good thing.

I am leaning towards a stiffer longer spring (if I can find one) up front and removing the sway bar. I may go with another shock if needed.

The rear maybe two new springs and putting a lower bump stop on it to increase my rear wheel travel and possibly making a QD for the swaybar. The lift kit added a 4 inch higher bump stop maybe I can cut that in half or I wonder if I can take it out and pick up the whole 4 inches???

 

[iamdub]

I agree 3.2 would be easier and fine on the street or wont contribute to wear but, it might help keep it more stable at high speeds off road. I have been know to hit 75mph on hilly back roads and twin tracks catching a little air with it... Rancho the lift kit maker recommends
Camber zero and -.3
Caster 4.5 +/- 1
Toe in .1 +/- .2
They got everything but the caster where I wanted it and even the caster is pretty close I think if I get the left side up I might be able to get the numbers a little closer too. Or maybe I will need to get a new adjustable upper control arm.



James, all of those are new I replaced them when I put the swaybars back on... I am thinking of disconnecting the front sway bar again to free up the front suspension off road. I will check the height again after I do the disconnect. Without the sway bar having a little extra caster should be a good thing.

I am leaning towards a stiffer longer spring (if I can find one) up front and removing the sway bar. I may go with another shock if needed.

The rear maybe two new springs and putting a lower bump stop on it to increase my rear wheel travel and possibly making a QD for the swaybar. The lift kit added a 4 inch higher bump stop maybe I can cut that in half or I wonder if I can take it out and pick up the whole 4 inches???

Since the left side is your problem side, I'd resolve the height difference first. Having the arms on that side at a hair more angle (at least at the same angle as the right side) may let them get the caster closer to your spec. You also have to keep in mind that, due to manufacturing tolerances, it may not even be possible. The frames aren't perfectly symmetrical from the factory but this is compensated for with the adjustable suspension. This isn't even counting the fact that your rig has been subjected to some relatively aggressive off-roading. Maybe that left side took a hard bump at one time and the frame is ever-so-slightly tweaked?

When determining your bump stop height, be sure to account for the shock's maximum compressed length. You want the axle to hit the bump stop before the shock bottoms out.

 

[91RS]

That’s called the “GM lean” and is normal.

I really wouldn’t suggest putting the caster at 4.5*, that thing will be very touchy on the highway.

 

[Tozan]

That’s called the “GM lean” and is normal.

I really wouldn’t suggest putting the caster at 4.5*, that thing will be very touchy on the highway.

Actually the more caster you have the more stable and less touchy it will be on the highway or off road. So setting it at 4.5 is not a problem at all. In fact it makes more sense for a lifted off road vehicle to run a slightly higher caster.

When the caster is out of balance like mine it may cause a pull to the lower side but, on mine it is not noticeable. But if I can get the other side up around 4.25 it would be best.

When I did alignments for a living I preferred setting up the left side .2 degrees lower to offset the road crown. I have never heard of a "GM lean" nor seen it as being a normal thing...

 

[91RS]

No. That is not the case at all. More is not better just because and having a caster split just because isn't better either. Caster is related to the suspension geometry so "high" is relative to each individual vehicle. 4.5* is high for these trucks, especially when the spec is around 3*. I've driven and aligned hundreds of these trucks and 4.5* will drive like crap. So unless your lift kit says you need to set the caster at 4.5* because they've changed the angles and such, you need to set it at the factory spec.

 

[iamdub]

I have never heard of a "GM lean" nor seen it as being a normal thing...

The GM Lean is real and it WILL GET YOU! It's everywhere with GM trucks from the old S-series to the trucks to the RWD SUvs. It's not noticed by many at stock or lifted heights but people go ******* after lowering cuz the "kit lowered the driver's side 1/2"-3/4" more". No, that side was always lower and just never noticed. I recall from my S-series days that people commonly ordered a spacer from Belltech to fix the lean when dropping their rides. It was just a polyurethane coil spring spacer sold individually.

I reduced the lean to almost nothing in my Xtreme by replacing the stock driver's side fuel tank that was located in front of the axle with one that went behind the axle, centered between the frame rails, relocating the battery to the rear and swapping the coils and leaves left-to-right.

 

[Tozan]

No. That is not the case at all. More is not better just because and having a caster split just because isn't better either. Caster is related to the suspension geometry so "high" is relative to each individual vehicle. 4.5* is high for these trucks, especially when the spec is around 3*. I've driven and aligned hundreds of these trucks and 4.5* will drive like crap. So unless your lift kit says you need to set the caster at 4.5* because they've changed the angles and such, you need to set it at the factory spec.

Do some research on caster because more in this case and in any case will certainly make it more stable. This is true with cars, motorcycles and even shopping carts. More caster makes anything want to go straight with more stability. You said it would be less stable and that is not the case at all geometry and physics does not support that statement at all.. 4.5 is driving just fine right now.. On the road and off road at high speeds so don't tell me it will drive like crap I already know what it drives like..

Also do you know the stock specs and tolerance?

So far as right and left not being the same look at the post below this guy (you) said the caster should be... You also stated 4.5 +/- 1 Now in modern or old math that means it could be as high as 5.5 and still be in specs... Also if you actually read my post you would see I stated " The company who made the lift RECOMMENDS 4.5

Actually it looks like wheel size didn't matter on a Tahoe, only Avalanche. Here are the specs for your K1500 2003 Tahoe (4x4):

Caster:
L: 3.50° ± 1.00°
R: 4.50° ± 1.00°
Cross Caster (L-R): -1.00° ± 0.50°
Camber: +0.25° ± 0.50°
Cross Camber (L-R): 0.00° ± 0.50°
Total Toe: +0.10° ± 0.20°
Steering Wheel Angle: -1.0° ± 3.5°

Plus since you wanted to post resumes here is my short list. I am a mechanical engineer, I was a designer for motorcycles, I also did the chassis set ups for the National factory Suzuki race teams as well as thousands of others in our chassis shop. I specialized in automotive alignment as far back 1976 and I certainly know what caster, camber, toe and thrust angles are and what they do.

So thank you for your comments but I really don't need them anymore.

 

[91RS]

I don't need to research anything, I'm well aware of what the measurements do. I didn't say anywhere it would be less stable, I said it will be touchy at speed (and at speed is what you were concerned with) and then said it will drive like crap (because of being touchy). And I say this because I literally know from driving hundreds of GMT900's before/after doing alignments where people have cranked up the caster trying to make the camber "green" instead of setting to specs. I'm not just pulling stuff out of my tail. I also said unless your lift kit recommends that because the lift has changed the geometry of the suspension. I did miss your other post where you said they recommend 4.5* but either way, I still think 4.5* is a bit too high but it's your truck so do what you want.

If that really is a quote from me, it was from a thread in the GMT800 forum because it clearly says 2003 Tahoe which is a completely different body style and has different specs...

So to answer your question, check all the bushings for being worn and that the pins for the adjustment cams haven't fallen out of the frame. You may have to accept a little negative camber to get the caster where you want it and make the other side match.