Jump to content

Recommended Posts

Posted
1 hour ago, SilveradoRST said:

 

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?  

 

 

For future calibrations, yes its documented in GM's system for programming.  If the installing dealer attached the install to your VIN it would show in the service history as well.

 

What it won't do is update the build sheet.  Any time you have it aligned, I would make sure they use the +Z7X specs.  

 

The instruction sheet for the GM lift says at the bottom to always align with the +Z7X specs after install and for future alignments.  

  • Thanks 1
Posted
Just now, Grumpy Bear said:

 

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. 

 

 

You are probably on to something however, the GM 2 inch lift is both front AND rear lift.  So I don't "think" the rake should change?  Control arms don't change, the struts are replaced with taller struts, blocks in the rear.  

Posted
12 minutes ago, newdude said:

 

 

You are probably on to something however, the GM 2 inch lift is both front AND rear lift.  So I don't "think" the rake should change?  Control arms don't change, the struts are replaced with taller struts, blocks in the rear.  

 

That makes some sense. 😉 Be worth measuring before and after next time you do one. Thanks for all the great input you willing give. It IS appreciated. 

Posted (edited)

What necessitates the need for steering re-calibration? I put the Eibach struts, springs and shocks on mine. Got just under 2" on the front and even a slight bit on the back. They had to align it three different times to get the steering wheel centered. However, it does seem its a lot more touchy than it was prior. It seems to track straight but if you bump it ever so slightly one way or the other it goes off that direction.

Edited by Byrds8
Posted (edited)
21 hours ago, Grumpy Bear said:

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:

 

 

 

 

 

 

 

 

 

 

 

 

 

Front end specs are dependent on Ride Height of the car, the moment you change the ride height throw the original specs out, these trucks have different specs for different option codes and spring weight rating and suspension. So that’s why I said that, if it handles and tracks good its FINE, no tire wear and he will be happy. The pre alignment road test is the most important to see and feel whats the vehicle is doing on the road,handling and tracking, this will determin if and how much  you will need to make caster adjustments. The Pre road test is more important than the post road test.   I have done alignments all my life, Caster is not a tire wear angle it’s a Stability angle and Handling/Tracking, can be used to correct for road crown correction, I said if it handles properly don’t worry about it, many cars on the road have caster WAY out of spec and they still track and handle well. Stop over and see me, I will invite you to the school where I teach and we can show you on our Hunter Hawk Eye Alignment machine and help you understand my recommendations.

I personally like 4 deg caster on both sides, 0 deg camber, .010 toe total slit on each side. this way I can get close to 100K miles on quality tires.  I also was able to get those adjustments from mine with a 2” top strut spacer in front and 1” spacer in rear and I have plenty adjustment to move it around, many different spring rates and suspension.

Edited by rbdjr
Posted
1 hour ago, rbdjr said:

Front end specs are dependent on Ride Height of the car, the moment you change the ride height throw the original specs out, these trucks have different specs for different option codes and spring weight rating and suspension. So that’s why I said that, if it handles and tracks good its FINE, no tire wear and he will be happy. The pre alignment road test is the most important to see and feel whats the vehicle is doing on the road,handling and tracking, this will determin if and how much  you will need to make caster adjustments. The Pre road test is more important than the post road test.   I have done alignments all my life, Caster is not a tire wear angle it’s a Stability angle and Handling/Tracking, can be used to correct for road crown correction, I said if it handles properly don’t worry about it, many cars on the road have caster WAY out of spec and they still track and handle well. Stop over and see me, I will invite you to the school where I teach and we can show you on our Hunter Hawk Eye Alignment machine and help you understand my recommendations.

I personally like 4 deg caster on both sides, 0 deg camber, .010 toe total slit on each side. this way I can get close to 100K miles on quality tires.  I also was able to get those adjustments from mine with a 2” top strut spacer in front and 1” spacer in rear and I have plenty adjustment to move it around, many different spring rates and suspension.

Wouldn’t out of spec caster eventually cause increased wear and tear on the suspension and power steering components?  

  • Like 1
Posted

 

 

7 hours ago, SilveradoRST said:

Wouldn’t out of spec caster eventually cause increased wear and tear on the suspension and power steering components?  

Not the caster on his truck, not even close, maybe in extreme cases, but I’m sure you would feel some handling conditions, wander, pull, steering wheel returnability etc

Posted

Hey all, just wanted to provide an update. Went to the dealership and had them look at my alignment. As previously mentioned, it seemed to be aligned to Trail Boss specs. Service Tech was able to dial it in to oem specs. He also noted that the caster was no where near maxed. Drive it about 35 minutes home, mostly highway and everything feels solid and tight. Thanks for all the input fellas!

  • Like 3
Posted (edited)
3 minutes ago, Black and Blue Z71 said:

Hey all, just wanted to provide an update. Went to the dealership and had them look at my alignment. As previously mentioned, it seemed to be aligned to Trail Boss specs. Service Tech was able to dial it in to oem specs. He also noted that the caster was no where near maxed. Drive it about 35 minutes home, mostly highway and everything feels solid and tight. Thanks for all the input fellas!

 

 

Good to hear they got you squared away and nice to see an update on this.  

Edited by newdude
  • Like 1
  • 1 month later...
Posted
On 3/9/2022 at 8:32 AM, Black and Blue Z71 said:

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.91821.thumb.jpeg.2130a3665969564b8ef32d8a3845c7a2.jpeg

 

On 3/9/2022 at 8:32 AM, Black and Blue Z71 said:

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.91821.thumb.jpeg.2130a3665969564b8ef32d8a3845c7a2.jpeg

Good evening.  I wanted to check in and see if you were able to get our truck aligned.  I am running into the same problem.  I have a 2021 GMC Sierra SLT 1500.  Just added a BDS 4 inch Suspension lift and the install shop, recommended by BDS, could ot get the truck in alignment.  I do not have a print out or remember what the descrepancies were, but from what I say, looked alot like yours.  So just checking with you.  My truck is still at the shop.  Thanks.

Posted

Hey, yes, the dealership was able to fix my alignment.  Driven roughly 500 miles since I last updated the post and all is good. I had a 1.5 leveling kit installed and the shop used Trail Boss alignment specs which put the truck out of alignment. Possibly the shop is using AT4 specs for your truck? Good luck!

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
  • Latest Articles

  • Posts

    • I’m out of ideas on this truck. 2020 Silverado 1500. 5.3 135,000 miles. Has a p0308 and p050d codes. Smokes From exhaust when cold. Compression test passed. New plugs, wires and coil on cyl 8. Same issue. New coil on 8, no change. Replaced injectors, no change. Bore scope showed oil pooled on the piston after sitting overnight. Pulled head and had machine shop check it out. No cracks. Stem seals looked good, replaced anyways. He also ground valve seats. Put it all back together and still have the same issue. Bore scope shows oil on the piston again. Leaning towards maybe a cracked ring but unsure. Cylinder looked good when the head was off, no scoring or scratches. Any ideas on what else I should look for?  Appreciate the help 
    • Just want to make sure it is covered by Special Coverage N232395310 Evaporative Emission Purge Pump 2021 Silverado 1500 Custom 2.7L L3B ~100k miles I'm getting DTCs P146B and P146F. VIN 3GCPWBEK2MGxxxxxx   I spoke to a person that works at GM and he said it is not covered after checking my VIN.   Is there anyone here who currently works for a GM/Chevrolet dealership and has access to GM Global Warranty Management / Investigate Vehicle History who could explain how the VIN eligibility is determined?   thank you    
    • Thanks for all that information, I might purchase one and see if it will work for me, if not they may let me return it! Yes for sure the tires are definitely within limit for my truck empty, and when I do tow I'll definitely make sure to raise the rear psi for the amount of weight that's going to be on it.
    • Yes exactly, more and more these days people/companies are afraid of liability issues so its easier just to say no rather than risk putting their neck on the line.    I will say with the Autel unit or when I used it last year on my truck, it wasn't like I could choose the 2025 model year or even the 2024 model year as that option was not there to manipulate the placard pressures but had to go back to 2023 or there abouts and then it showed up as an option, odd but that was how the software was then and I can't say one way or the other now as they throw out updates every so often. I still would talk to your tire dealer though to start with and they may do it for nothing but also they may have a comment on a better unit to purchase. All I know is that one of the large tire shops in my area happens to use these Autel units for their use and set them up to use the wifi and all of that jazz for constant updating because each tire tech has one handed to them by the shop but I just plugged it into my laptop to update it and yes if one is bought it has to be registered so you can get the link to do updates and then the unit has to be updated before its even used. I am not at all techy so it took me a bit but anyway just a heads up for anything you buy, most likely it will need to be connected to a computer to access the internet to have it updated to the latest software version before you can put it to use.   If your truck is near empty, those tire pressures you listed are a very safe upper range pressures to carry the weight, both the front and rear as I know they could be run lower yet with an empty truck. And if its a trailer and not some motorcycle your going to strap onto the front of your truck on a rack, you shouldn't have a need to inflate your front tires if your at 55 front already, its the rear ones that would need more air if you have much hitch weight. 
    • Thank you, I'll check that Autel scanner out and see if it will work for me! Ya I can see GM's point of view if they lower the psi set value for someone and the person sell's the truck and the new owner puts the factory tires back on then their could be liability issues cause the psi warning light wasn't coming on when the tires were under inflated for towing their load and then it might be able to be traced back to GM lowering it.
  • GM-Trucks.com Clubs

  • Popular Contributors

×
×
  • Create New...