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2007 Thunder Gray CTS-V
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Discussion Starter #1
I took measurement of thrust angle, camber and rear toe and found the rear end badly needing some adjustment. No big deal I thought, until I raised the car to look at the adjuster and here's what I found:

This is the rear left adjuster has slipped inward to the limit, and it can be seen that there never has been a wrench on this adjuster nor any other suspension adjustment on the whole car. Further, the car has never been wrecked and there are absolutely no dents. the camber is at -2.0 degrees, so with this adjuster at the limit, the problem must be somewhere else. The upper control arm can't be shimmed and I can see no frame damage whatsoever, so my natural conclusion is that the control arm bushings are bad. I can't move them with a pry bar to prove them bad, so I'm asking if there is something about the Caddy suspension I don't know or am not seeing. Is there another way to take out negative camber other than the adjuster on the lower control arm. Second question, is there anything particular about the bushings failing and causing this.

Just for info, LR Camber: minus 2.0 deg, RR Camber minus 1.8 deg, Rear Toe: + 0.3 deg, Thrust angle greater than .8 deg aimed to the right. Front is a liittle better, Right camber minus 0.8 deg, Left Camber minus 0.35 deg, Total Toe +0.3deg. didn't check caster yet.
 

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2005 CTS-V
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I can find nothing in the service literature that addresses your issue. There is technical service bulletin that discusses a kit to provide more negative camber to the front suspension, but none that I can find for the rear suspension.
 

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2007 Thunder Gray CTS-V
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Discussion Starter #3
Thanks. I think I see that the lower outer bushing is not centered in the hub of the spindle, and that part is available from a parts store, so I may go ahead and replace all the bushings, and as a last resort, elongate the adjustment slots to get the right camber.
 

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2007 CTSV Thunder Grey / 2010 SRX 2.8T
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I'm not sure I was following 100%

are you saying you are at -2 degrees currently, and that the picture shown is the adjuster for the upper rear control arm? If my perspective is correct you cannot gain any additional negative camber based on this adjustment. but you could move more positive if you liked. The FAQ indicates that the alignment adjustment likely max out around -2 so I'm not sure if you can expect much more. FAQ alignment specs

I'll try to look under mine and see where I am at, and find my alignment sheet from last year. I think I had it set at -1.5 so in theory there should be a bit of adjustment available on mine. I do have new bushings (poly) in my rear upper control arms.
 

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05 Stealth Gray V
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I haven't aligned mine personally so I'm guessing that is the adjustment on the lower control arm and as it is all the way "in" there is no negative camber left to take out and you've stood the wheel up as far as it's going.

The spec is -1.5 plus or minus a half so technically, it is still within spec.

I aligned front ends for years and have been on here for several years beyond that and this is the first post I can remember seeing about rear camber concerns. Could this be typical for this platform?

In other words, if you can take a pry bar to the suspension components and not get any appreciable "slop", I'd let it roll for now unless it is absolutely eating tires up. Otherwise, you might just be throwing parts at it.

I would also check the cradle mounts. If one side has failed and the other side hasn't, you could get some screwy numbers....
 

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2007 Thunder Gray CTS-V
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Discussion Starter #6
According to Hunter specs, rear camber is -1.0 +/-0.5, so I'm 0.5deg off the limit. so are they right or the factory? If I planned to track the car, I'd crank it out and It is wearing the inside of the tires, so unloaded it must be scuffing. i corrected the toe and thrust angle but had to leave the camber in until I find the fix. I saw a front cradle, but didn't notice a rear one, so back on the lift she goes. One thing, the suspension seems tight. I can drive it, check camber and it is always the same both sides.

The front was out, but it came back no problems.

just to make 100% sure, both the factory spec and the Hunter spec show no sign for the toe angle (which to me means POSITIVE toe, or TOE IN). So both front and rear toe IN, correct?
 

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2007 Thunder Gray CTS-V
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Discussion Starter #8
Yep old guys forget stuff. Growing old is mandatory, growing up, optional. I beat and banged on the rear suspension for a half day trying to get the rear camber out with no luck. All the bolts are clean now, though.

It would be interesting to see what the camber is on other CTS-V's and how much adjustment there is left. ctsv247 has a point, I might be chasing a rabbit on this one.

Anyone near Huntersville NC that wants a quick alignment check, send me a note.
 

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The specs you first posted show -1.5 degrees camber plus or minus a half so somebody is wrong. No sign in front of the toe spec means toe in and if you notice, it could be zero and still be more or less in spec.

Automotive alignment isn't as precise as you might think. Because there is play in all of these suspension components (it there wasn't, the suspension wouldn't be able to move) the alignment is constantly changing in motion and because of this, you will very rarely get the exact same numbers twice when you check and recheck alignment specs. This is more true with toe than camber or caster and you will also see this more on the front than you will on the rear as you have a steering rack adding even more "slop".

In other words, you can drive yourself nuts trying to get one perfectly speced by the book. If it drives well and seems to be wearing tires acceptably, leave it be for street duties because perfection isn't an option on a mass produced automobile.

That being said, I would sacrifice a little handling prowess for a few more miles out of my tires so I was thinking about dialing in as much positive camber as I can as any car with a -1.5 degree camber spec will wear tires unevenly to some extent. Some on here have combatted this theory but they are driving their cars harder than I am and I'd bet that applying torque is more of a tire wear issue for them than it is for me as I commute 120 miles on the interstate everyday. In my experience, if the tire isn't flat on the ground, it won't wear evenly across the entire face of the tread. Any fluctuation more than .5 degree from zero either way will tend to accelerate tire wear in my real world, mommy's minivan alignment experience.

I live in Gastonia but work at the BMW plant in Greenville, SC and commute back and forth. Going to the Autofair?
 

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05 Stealth Gray CTS-V, 08 Light Platinum SRX V8, 05 White Diamond STS4 V8 1SG
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A couple things. First, my car has, if I recall, somewhere in the -2d rear negative camber and even -1d negative front camber and I like the way it handles. Second, toe is extremely important for tire wear on vehicles that run with negative camber. Even the slightest negative toe will kill your inner tread. Finally, your alignment is really set for your driving style, with regard to tire wear. Someone who does a ton of highway miles is going to want a more mild alignment than someone who pushes the car on a regular basis. A mild alignment and hard cornering will just end up wearing the outside of the tread since the tire is rolling over, so it goes both ways. Not to mention for me, I like the way the car feels neutral. If I had a spec alignment, I think the car would understeer too much for my preference.

Looking at the "aggressive street" settings on the FAQ, i agree with them for that application, if that helps.

I had an alignment done by this old school guy in NC many years ago and he found no way to adjust rear camber. We didn't really need to but apparently it's on the upper control arm bolts...
 

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2007 Thunder Gray CTS-V
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Discussion Starter #11
I'll be at the Auto Fair,some, but waiting to see what the rain is.

I just got the car and I'm in the long process of restoring the neglect the previous owner used to punish the car. I saw tire wear on the inside edges in the rear and some cupping in the front, so my goal in restoring alignment was to bring the car back to the middle range of the spec so I could further assess the tire wear issue I see.As far as I can tell, there is only one point for adjustment for camber in the rear, the slot in the photo in the first post of this thread. The lower arm has two pivot points, one at the frame and one at the spindle. Both are cylindrical bushings, no ball joint here. The upper arms in the rear are A-arms with a ball joint at the spindle, and two cylindrical bushings that connect to the frame with bolt pockets that have no adjustment. The upper A arm is similar to the upper A arm on a C5/C6 Corvette. Toe is adjusted with a toe link that has a cylindrical bushing on each end. This toe link had the toughest threads to break. They had never been loosened and were corroded tight. However, it is interesting that once broken free, the adjustment is pretty fine and easy to bring into spec.

I'm to the point where I'm ready to take the suspension apart and really learn why the rear camber range is biased to the negative. This is a piddlin' car; one I don't need to use, so I have time to sort it out and I like challenges. Since both sides of the rear are the same, I suspect this is just the way the car was built. if that is the case, I will probably lengthen the adjustment slots to the inside. All I will need is 3/16" more and I think I can get to mid range spec. I'm not as worried about handling performance at this point. Anyone that lives in what we used to call the METROLINA area will tell you there aren't many places any more where you would need an aggressive alignment. Unless you are out at 3 in the morning, the roads are crowded. If you are out at 3am with a CTS-V with tinted windows, you would be a police-magnet.
 

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Slotting the frame isn't the right way to do it but I'd be a liar if I said I never did it to help someone out. The better option is to have the frame "spread". They chain down both sides and push up in the middle and voila, you have positive camber. Not a big deal at the frame shop.

Pulling it apart to inspect it all? You may as well just replace it all because all of it will have wear and all of it will be contributing to some extent to your negative camber situation. You may find one part that is worn more than the others but if you actually had "bad" parts, an experienced front end guy could find it without tearing it down.

Looking at the bump stops will usually tell the story. If they are beat up or deformed or the frame is dented where they've been repeatedly bottoming the car out, someone has been playing dukes of hazard with the car and the frame, sub-frame, uni-body whatever has settled in the process.

What kind of runouts did you get?
 

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2007 Thunder Gray CTS-V
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Discussion Starter #13
I thouight I would update everyone, I think I found the problem in the rear.I can see a small gap between the bushing and the upper control arm pivot bore. It is very hard to see up there, but that 1/16 could be enough to throw the alignment to where it is.
 
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