[hawk02]

I'm getting ready to have a four wheel alignment done. I found this thread over in the mechanical maintenance section:

www.camaro6.com/forums/showthread.php?t=502324

According to the 2017 Camaro service manual, the rear camber and toe alignment bolts are single use fasteners and need to be replaced anytime they are loosened.

The part number for the rear camber bolt listed in the thread says it does not fit a 2017 ZL1.

Has anyone done a rear alignment on their ZL1 and replaced the camber and toe bolts? If so, what part number did you use for the rear camber bolt?

[hawk02]

Paid a visit to my dealer today. The person at the parts counter ran my vin and confirmed the part number for the rear suspension lower control arm inner bolt (a.k.a the camber adjustment bolt) is 11547215.

This is the correct part number even though all the online GM parts sites indicate it does not fit a 2017 Camaro.

[Sooner Cole]

Originally Posted by hawk02

Paid a visit to my dealer today. The person at the parts counter ran my vin and confirmed the part number for the rear suspension lower control arm inner bolt (a.k.a the camber adjustment bolt) is 11547215.

This is the correct part number even though all the online GM parts sites indicate it does not fit a 2017 Camaro.

Good information. I am curious why the bolts are one time use?

[hawk02]

Originally Posted by 17ZL1Camaro

Good information. I am curious why the bolts are one time use?

That's a good question. Especially considering the front toe and camber adjustment bolts are multiple use. Must be the added strain of the drivetrain on the rear suspension parts. Just a guess.

[Stephen12ZL1]

people on the Facebook groups are calling BS on camber adjustment bolts and toe link bolts being “one time use”. I find it hard to believe as well. What happens if you retorque and it needs a slight readjustment? Throw the bolts in the trash again? I doubt it is an issue at all.

[hawk02]

Originally Posted by Stephen12ZL1

people on the Facebook groups are calling BS on camber adjustment bolts and toe link bolts being “one time use”. I find it hard to believe as well. What happens if you retorque and it needs a slight readjustment? Throw the bolts in the trash again? I doubt it is an issue at all.

Well, all I can say is the service manual explicitly says to discard the bolt and install a new bolt. Obviously, everyone can do whatever they feel comfortable with. For me, I will be replacing bolts if alignment is needed.

2017 Chevrolet Camaro | Camaro Service Manual 10049487 | Suspension | Wheel Alignment | Repair Instructions | Document ID: 2859641

Rear Camber Adjustment

Caution: This vehicle is equipped with torque-to-yield or single use fasteners. Install a NEW torque- to-yield or single use fastener when installing this component. Failure to replace the torque-to-yield or single use fastener could cause damage to the vehicle or component.
1. Rear Suspension Lower Control Arm Inner Nut(1)»Remove— Lower Control Arm Replacement
2. Rear Suspension Lower Control Arm Inner Bolt(2)»Remove
DISCARD the bolt.
3. Rear Suspension Lower Control Arm Inner Bolt(2)»Install
Install a NEW bolt.
4. Rear Suspension Lower Control Arm Inner Nut(1)»Install
5. Rotate the rear suspension lower control arm inner bolt (2) until the correct camber measurement is achieved. Wheel Alignment Measurement
6. Check the alignment specification and re-adjust if needed. Wheel Alignment Specifications
Caution: Refer to Fastener Caution.
Note: Tighten the nut and bolt enough to maintain the adjustment. Verify the camber reading prior to tightening the bolt to its final torque.
7. Hold the NEW rear suspension lower control arm inner bolt (2) and tighten the rear suspension lower control arm inner nut (1).
Tighten
First Pass: 115 N•m (85 lb ft)
Final Pass: plus 75-90 degrees

© 2017 General Motors. All rights reserved.

[cwebster]

While getting my Hoosiers mounted today I made an appointment with service for tomorrow to do a 4-wheel alignment. My last 3 sets of tires have been wearing unevenly, partly do to favoritism of the right wheel by the eLSD and partly from poor alignment.

I mentioned these torque-to-yield bolt replacements on the rear and their lead mechanic said "No - I don't think so." I insisted they check their manual and sure enough it's right there in red-and-white. Unfortunately, that's not something they have in stock. Faced with this, the mechanic says "Well, you can always use them one or two more times...". At this point I just told them to order the bolts. I'm not trusting my life to someone's intuition when I could be moving 170 MPH or more.

I was a helicopter crew chief/mechanic for half of my USMC career so I know a little something about high stress fasteners and torque. The "Jesus" nut that holds on rotor heads is one such animal. If the manual says you throw that bolt or nut away, you shit-can it... period. People have lost their lives from failed Jesus nuts. I don't want to be the first ZL1 driver to hit the wall because I cheaped-out on fasteners.

If anyone needs more background information on how this works, check out this very detailed description of torque-to-yield fasteners: How to Understand Angular Torque and Torque to yield

Hopefully, I won't go through tires as fast if they wear more evenly.

--Cal

[waterman]

Good call on replacement. The bolt probably has a high torque spec. due to its application.

Even high tensile grades (US grade 8 or A325) or class (metric 10.9-12.9) bolts used at a high torque spec. can stretch. Either the bolt itself, the threads or both. There is however slight or great, a definite potential for compromise. Head bolts are the classic example of single use fasteners due to the potential for stretch.

With all of the moving parts, thrust and torque associated with suspension, why take the chance? Just my $0.02.

[hawk02]

I just ordered two of each bolt from That GM Parts Guy. $34 with shipping. Cheap insurance to prevent potential failure of the rear suspension far as I'm concerned.

[cwebster]

Originally Posted by waterman

Good call on replacement. The bolt probably has a high torque spec. due to its application.

Even high tensile grades (US grade 8 or A325) or class (metric 10.9-12.9) bolts used at a high torque spec. can stretch. Either the bolt itself, the threads or both. There is however slight or great, a definite potential for compromise. Head bolts are the classic example of single use fasteners due to the potential for stretch.

With all of the moving parts, thrust and torque associated with suspension, why take the chance? Just my $0.02.

Exactly! I think the point some folks aren't getting is that these particular bolts and TTY method are specifically engineered to stretch to the point of plasticity (as explained in the OP reference thread). It WILL NOT return to its original length. More importantly, the next time you apply the same torque-to-yield method it will either break apart or be severely weakened - ready to break.

--Cal

[waterman]

Originally Posted by cwebster

Exactly! I think the point some folks aren't getting is that these particular bolts and TTY method are specifically engineered to stretch to the point of plasticity (as explained in the OP reference thread). It WILL NOT return to its original length. More importantly, the next time you apply the same torque-to-yield method it will either break apart or be severely weakened - ready to break.

--Cal

Plasticity, that was the word that I was looking for. Bravo.

Thanks for your service cwebster.

[Torquem]

It always amazed me the cheapskates that would reuse the torque-to-yield crankshaft bolts on the LS1.

[cwebster]

Originally Posted by waterman

Plasticity, that was the word that I was looking for. Bravo.

Thanks for your service cwebster.

Thank you waterman. I learned a lot of lessons in those 21 years. Hopefully, I can pass on some of what I learned before it's time to go.

Originally Posted by Torquem

It always amazed me the cheapskates that would reuse the torque-to-yield crankshaft bolts on the LS1.

I think a lot of that is just ignorance. I've done a few bonehead things like that too. Back in the 80s I did a simple small block rebuild so I could have a cheap truck. With a growing family and shrinking paycheck, as a young Marine I had to be very frugal (cheap). My decision to not buy new connecting rod nuts was an expensive lesson. I was so proud of myself for match-marking everything when it cranked over and purred like a kitten on the first attempt. 2-miles into my test drive I heard an increasingly loud clacking noise. Before I could turn off the motor I'd thrown a rod through the crankcase. Lesson: I should have at least checked the run-on torque. Some things you can re-use and some things you can't. The key is developing the wisdom to know or learn what you need to make a good decision. Back then we didn't have the Internet so it all depended on books you could lay your hands on and experience of people you knew.

--Cal

[Stephen12ZL1]

Time to call Fastenal and get a bolt for that adjustment point that doesn’t require “s-canning” after every torque event (which I still believe to be BS). This isn’t a helicopter rotor jesus nut either and understand that to be a completely different situation. If this area was so “high stressed” like a helicopter rotor, I would definitely replace. Has anyone ever heard of a bolt in that control arm which failed due to its reuse? I doubt it. Fifth gen cars have the same bolts in that location and I had mine adjusted many times. I suppose I was cheating death, and I’m lucky to be typing this sentence.