Alignment after Leveling

Black and Blue Z71 · March 9, 2022

Hey all, recently put Pro Comps 1.5 leveling kit on my 2020 Silverado 1500 z71. Got it aligned after and the shop said my caster was almost maxed out from the factory and were only able to make some adjustments. I put the print out below. Is this normal or cause for concern? Appreciate any insight.

winks79 · March 10, 2022

I have a 2019 Sierra SLT 4wd that I put Bilstein 5100's on and leveled at 1.5 inch. When I had mine realigned was nothing like that. Guy had to do very little and everything was put back to normal. Have not had any issues. If that is the specs after an alignment something is bad wrong. I would have someone else check.

Black and Blue Z71 · March 10, 2022

Interesting to hear that minimal adjustments were needed on your truck compared to mine. Those are the specs after the alignment was done. Truck tracks straight and drives normal. Definitely thinking I should go to another shop and have them take a look.

rbdjr · March 10, 2022

For me those readings would be perfectly fine as long as truck tracks straight and handles ok down the road, cross caster is a bit higher than I like to set, I prefer 1/2deg more on RS than left to fight road crown on most secondary roads( yours currently 1 deg) , but if it tracks straight and handling ok leave it alone, Caster has no effect on tire wear, so those are good if good for you. Camber and Toe looks fine. Keep a close look on tires and rotate tires every oil change its worth it in the end.

I also installed a level kit in my 2021 RST4x4 3.0L 4door,short bed. I installed top spacers in front and 1" spacer in rear. redid alignment , I did notice you must really torque lower control arm eccentrics to spec and they do tend to slip when hitting large bumps/potholes especialy if you sprayed with penatraint before adjusting( lesson learned myself) I did have plenty adjustment as they are very adjustable if needed, Caster/Camber and Toe. Some times you must start from scratch and create a new starting point with eccentrics, and not try to just to adjust from where they set from factory.

Black and Blue Z71 · March 10, 2022

Great info, really appreciate it! Good to hear that the caster isn't terrible. I am diligent about rotating the tires so I'll definitely keep on that!

Grumpy Bear · March 10, 2022

Why would anyone tell anyone else that a spec out of spec it okay?

Needs MOOG extended caster bolts installed and your alignment man replaced.

:idiot:

LEFT side IF different not more than 1/4 degree MORE positive caster. Equal is fine.

LEFT side 1/4 degree MORE positive camber which when you decide to run negative camber is less negative left.

.04 to .05 POSITIVE toe is great and there is no reason other than laziness for it to not be dead on identical. It is literally the easiest of the specs to hit.

Trust angle as close to zero as possible. Steer ahead zero.

This alignment was good for 125K miles on factory 60K tires when rotated, balanced and inflated routinely.

HUGE caster angles make the ride harsh and adds stress to the power steering. Makes it heavy and turn in lazy. Corner like a snow plow.

Black and Blue Z71 · March 10, 2022

Thanks for the input. Do happen to know where to get the Moog kit for our trucks? Moog has our part number k100421 listed but I can't find it anywhere.

Grumpy Bear · March 10, 2022

Auto Zone will have or will order O' Reilly ditto.

newdude · March 10, 2022

I'd try another shop or have them redo it. Did they give you a "before" and "after" printout?

"Technically" they used the wrong specs and your caster was probably fine to begin with. Look at the top of their screen it says "Silverado 1500 4x4 dblcab +Z7X". RPO code Z7X is Trail Boss suspension, and you didn't install the GM Trail Boss kit, so those specs should NOT have been used during the alignment.

They should have aligned it as "-Z7X (minus Z7X)".

I cut the chart down just to double cab 4x4 with and without Trail Boss so you can see the difference in GM's specs:

Edited March 10, 2022 by newdude

Black and Blue Z71 · March 10, 2022

Great info and good catch on the trail boss specs. Yes they provided the before specs, I put them below. I scheduled an appointment for at a local dealership on Monday to have them look at it. Definitely not ideal....

SilveradoRST · March 10, 2022

1 hour ago, newdude said:

I'd try another shop or have them redo it. Did they give you a "before" and "after" printout?

"Technically" they used the wrong specs and your caster was probably fine to begin with. Look at the top of their screen it says "Silverado 1500 4x4 dblcab +Z7X". RPO code Z7X is Trail Boss suspension, and you didn't install the GM Trail Boss kit, so those specs should NOT have been used during the alignment.

They should have aligned it as "-Z7X (minus Z7X)".

I cut the chart down just to double cab 4x4 with and without Trail Boss so you can see the difference in GM's specs:

Sorry to hi-jack but this got me thinking. I had the GM Trail Boss Accessory Suspension installed back in Feb '21. So the dealer (further away from me) did the lift and alignment. They also did the power steering controller calibration as stated in the instructions. Fast forward months later, I felt my steering wheel was off-center. Constantly had to hold the wheel slightly left to track straight.

I went to my local dealership and had them do an alignment again, they said the toe was off a bit. The wheel is centered now but I get a bit of wandering, not terrible. I did mention to my local dealership I had the Gm 2" lift done at another dealer when I went in for the alignment. Is this something they would have know by looking up the VIN? Because an authorization code, VIN and a call to Techline was needed to do the power steering controller (per Lift Kit Instructions), is my VIN in the GM system now reflect that I have the 2" lift? Or am I completely wrong, VIN will show I have an RST and I'll have to always remind the dealer to use +Z7X when getting an alignment done?

c.schill · March 10, 2022

I just put 2.5" leveling struts on the front of my 2019 LT, and the alignment went fine. They were able to get everything perfectly in spec. Seems odd to me that with a lesser height spacer, they had that much trouble getting everything in spec.

Black and Blue Z71 · March 10, 2022

Definitely odd! I'm wondering if Newdude is onto something with them using Trail Boss specs on my RST Z71

newdude · March 10, 2022

3 hours ago, Black and Blue Z71 said:

Great info and good catch on the trail boss specs. Yes they provided the before specs, I put them below. I scheduled an appointment for at a local dealership on Monday to have them look at it. Definitely not ideal....

Yea, see your before caster is much more in line with the non Trail Boss alignment specs, perhaps even in the green if they had loaded in with the correct specs to start with. It should have been a toe and go more likely, or possibly a quick caster tweak followed by a toe adjust.

Grumpy Bear · March 10, 2022

3 hours ago, newdude said:

I'd try another shop or have them redo it. Did they give you a "before" and "after" printout?

"Technically" they used the wrong specs and your caster was probably fine to begin with. Look at the top of their screen it says "Silverado 1500 4x4 dblcab +Z7X". RPO code Z7X is Trail Boss suspension, and you didn't install the GM Trail Boss kit, so those specs should NOT have been used during the alignment.

They should have aligned it as "-Z7X (minus Z7X)".

I cut the chart down just to double cab 4x4 with and without Trail Boss so you can see the difference in GM's specs:

I'm going ask a question before I step in IT. Does this lift change the frame rake angle? Ever measure it?

I ask because when I did my lower via the back end it of course changed the frame rake when also changes the caster angle by the EXACT same amount. These numbers in this chart reflect the exact change in frame rake which means the 'ideal' caster angle is "Ideal' for GM in that changing the spec means no alignment required.

IF that sounds absurd I direct you to the TSB on the 2.4 ring and piston replacement that states that even at the 150K warranty limit to NOT hone the cylinders.

Or to the GM memo on further reducing of the OCI beyond the 2014 OLM recalibration to 7.5K.

Recalibration of the ABS to 'Band-Aid" a brake vacuum pump. No need to go on, eh?

Point is there is nothing in a lift or lower that would change the 'ideal' caster value Think about it. They have a habit of moving a spec instead of doing the work. IMHO of course.

The recalibration of the power steering adjust the 'assist' to reflect the higher input effort required to overcome an extra degree of two of caster.