[cdb95z28]

Originally Posted by Msquared

The other links don't matter. This isn't that complicated. The camber is adjusted by pushing the LCA out to get more negative camber, and the other links don't change their length or position. If you lengthen or push outward the LCA to get negative camber and no other links change their length/position, then the knuckle must also move outward overall (top of knuckle stays in same lateral position, bottom moves outward) as we add negative camber.

In the drawing, it's a view from overhead. It doesn't matter if the red LCAs are in the exact right position (they should be slightly behind the wheel centers), as long as they are ahead of the toe links (which they are). If you look at the actual rear suspension in plan view (i.e., from above), you'll see that the toe links are behind the LCA:

Attachment 1039493

Attachment 1039495

So there is no way that pushing the LCA outward would not increase toe out. The two semi-trailing arms (upper and lower forward-most links) would also pull the knuckle slightly forward and outward as we add negative camber. That may contribute even more to toe out, but I don't know if it's significant. OTOH, changing toe doesn't do anything to camber or caster. There's no need to "work them in unison." Camber changes toe, but not the other way around. As someone else just wrote, you set camber first and then fix the toe.

Aside from all that, it's a nailed-down, well known fact that adding negative camber to the rear of our cars pushes toe negative (out). I've watched it happen as my car was aligned. Toe out is the limiting factor in how much negative camber we can get on the rear of these cars. If it went toward positive toe (in) with negative camber, a lot of us would be running more rear negative camber because a little toe in might actually help some of the on-throttle oversteer characteristics of these cars on corner exit! Put another way, for a track alignment you can just set the toe links at their furthest-outward position (max toe out) and then add negative camber until you get back to zero toe. Bam - you're at max rear negative camber. That's all there is to it. You'll see it when you do your friend's alignment.

[TrackClub]

An update: just picked up my car. They have re-attached upper control arm and that alone gave enough clearance to give me a perfect track alignment, exactly according to my specs.

Thank you all for sharing your suggestions and opinions. It was all very helpful and for that i am grateful!

Cheers!

[m3bs]

Originally Posted by TrackClub

An update: just picked up my car. They have re-attached upper control arm and that alone gave enough clearance to give me a perfect track alignment, exactly according to my specs.

Thank you all for sharing your suggestions and opinions. It was all very helpful and for that i am grateful!

Cheers!

Reattached. Had it come loose?

[Msquared]

Originally Posted by TrackClub

An update: just picked up my car. They have re-attached upper control arm and that alone gave enough clearance to give me a perfect track alignment, exactly according to my specs.

Thank you all for sharing your suggestions and opinions. It was all very helpful and for that i am grateful!

Cheers!

That's...pretty odd. I can't see how that would happen. Is there any chance they replaced that arm because the other one was either damaged (maybe the bushings) or the wrong one? Or yeah (^^^), was it frickin' loose?

[TrackClub]

Not loose, just unbolted it, pushed it over as much as they could and then re bolted it. At least that's the official line.

[m3bs]

I'm thinking there should not be any slop in that connection, unless the bolt, bushing, or bolt holes are worn.

Understood. That's their story and they are sticking to it....

[DaveC113]

Good news!

[TrackClub]

I dont think this dealer would BS me. Small town, small dealer (with tons of Vettes), reputation is key, etc.
But i have no way of verifying it. Bottom line, they knew safety was my numero uno priority, i bought the car for track duty, etc. I dropped off the car last night and the service mgr called me at lunch, so it could not have been anything too involved, defo not a new part.


The print out they handed me nailed the specs exactly. So, i will continue my break in, then take it to an intermediate track and flog it. I know what the car ought to feel like after 60+ track days in my 17, so if anything is amiss i will know pdq. End of month test will be at Mosport, so this will be a first big test. Cheers!

[h018871]

Just found this thread.
1st, congrats on the fix TrackClub
2nd, I had a similar issue except it effected the RR. Couldn't get enough camber without the toe going neg.
There were 2 issues with my car:
1). The cradle was not correctly aligned with the body. I fixed that when I put the solid bushings in.
2). The cam bolt fences/brackets for RR toe were damaged. The forward fence was cracked and folded over on the inboard side and the rear 'pocket' opened up on the inboard side. This kept the eccentric toe pivot point too far inward = neg toe.

Fix was to push the forward fence back into place and weld a bead behind it to support it. For the rear pocket, hammer it closed. All good for now.

I only have a picture of the pocket before I hammered it closed.

[TrackClub]

Originally Posted by h018871

Just found this thread.
1st, congrats on the fix TrackClub
2nd, I had a similar issue except it effected the RR. Couldn't get enough camber without the toe going neg.
There were 2 issues with my car:
1). The cradle was not correctly aligned with the body. I fixed that when I put the solid bushings in.
2). The cam bolt fences/brackets for RR toe were damaged. The forward fence was cracked and folded over on the inboard side and the rear 'pocket' opened up on the inboard side. This kept the eccentric toe pivot point too far inward = neg toe.

Fix was to push the forward fence back into place and weld a bead behind it to support it. For the rear pocket, hammer it closed. All good for now.

I only have a picture of the pocket before I hammered it closed.

Thanks very much for your post!

I hope my car is all well now, but will have my mechanic check it over nevertheless, before i take it out on a track.
I will also take a close peek myself, something i could not do, due to access restrictions to a service bay at the dealer.

Again, thanks for the info! Cheers!

[Scargoes]

In a factory produced vehicle there is always some tolerance between bolted parts. SO what they did was to loosen the link, move to connection so it was loaded one way, then tighten the bolts again. It is not an uncommon practice. But the trick is to get the suspension at 1G(at rest like sitting in the garage and stationary) when you torque the bolts down. Not getting at the suspension at 1G will increase the wear on the rubber bushings due to the extra load on them once the vehicle settles. There is also a slight increase on spring rate due to the bushing being bound up.

[TrackClub]

Originally Posted by Scargoes

In a factory produced vehicle there is always some tolerance between bolted parts. SO what they did was to loosen the link, move to connection so it was loaded one way, then tighten the bolts again. It is not an uncommon practice. But the trick is to get the suspension at 1G(at rest like sitting in the garage and stationary) when you torque the bolts down. Not getting at the suspension at 1G will increase the wear on the rubber bushings due to the extra load on them once the vehicle settles. There is also a slight increase on spring rate due to the bushing being bound up.

I understand the concept, albeit i am not sure if things were not bound up more prior vs after (given my issue).
Is there a test of some sort to ensure all is properly and equally loaded? Or will wear over time tell the story?
Thanks for your input - appreciate it. Cheers!

[Msquared]

The good news is that proper loading before tightening the bolts will have been explicitly covered in the factory service manual. Hopefully, the tech who did the work will have paid attention!

[Scargoes]

Originally Posted by TrackClub

I understand the concept, albeit i am not sure if things were not bound up more prior vs after (given my issue).
Is there a test of some sort to ensure all is properly and equally loaded? Or will wear over time tell the story?
Thanks for your input - appreciate it. Cheers!

There really isn't a test. At my last employer (a manufacturer) all the departments had an assembly jig, similar to what was on the production line, that held all the suspension links at 1G for torquing before instillation. I'm not sure if Chevy service departments have a similar set up. If not, it can be approximated by using a screw jack at the knuckle(not suspension links) to compress the suspension until the axle shaft is horizontal. Then torque the links. Depending on which way you are trying to take up slack, this procedure could make it more difficult or easier.

As for the tech having done it because it is called out for in the service manual, One would hope they would do it. But it's not something I'd expect the average Tech to do because they usually don't care and it cost time.