C2 rear alignment questions

[Randy S.]

I noticed my RR wheel seems to have excessive camber. Best measurement with some combo squares and bubble levels is neg 2.5 deg.

I jacked the car up and could not feel any excesssive play at the tire and all the trailing arm shims look to be intact.

When last aligned 4 years and 7000 miles ago the shop added trailing arm shims ( new slotted style provided by me) and car was in spec RR @ -0.3 deg and LR @ -0.7 deg.

Is it reasobable to expect alignment to change this much or do I have other issues? I had the car shipped last year and I know he used the 4 slotted holes in the frame for his tie down points.

What should we look for when I get it to an alignment shop?

BTW rear toe in was set at 0.15 deg each wheel. Is there a conversion to inches

PS I am using radial tires

Randy

[Edward J.]

Re: C2 rear alignment questions

Randy, You Right About The Camber, Which is Adjusted With The Cam Bolts On Bracket Under The Rear Diff. The Shims You Refered To Bring The Toe Back Into Spec.s . You May Want To Check The Torque Struts Sometimed These Bushing Do Flatten Out And Are Hard To See, Unless On A Lift. One Last Detail If The Cam Bolts Are Not Properly Torqued The Alignment Will Slip.

[Bill M.]

Re: C2 rear alignment questions

BTW rear toe in was set at 0.15 deg each wheel. Is there a conversion to inches

Randy

Randy:

.06 degrees is about 1/32 inch.

Bill

[John D.]

Re: C2 rear alignment questions

It's no big deal to adjust the camber bolt to bring the top of the wheel out, I have an old modifed wheel alignment head I use. Shoot for levelor slight inboard (-0.5 is the spec I believe). Be sure to drive the car around and let the suspension settle before further adjustments.

[Duke W.]

Re: C2 rear alignment questions

Rapid build up of rear negative camber could be caused from rapid axle side yoke end wear. So you need to get the rear up in the air and measure yoke end play.

Basic tenet of Euclidean geometry:

The arc length subtended by a small angle (which is essentially the same as the chord, which is the toe measurment) is equal to the angle in radians times the radius.

In terms of toe in this means:

Toe (per wheel) = toe angle (per wheel) in radians x tire inflated radius.

There are 2Pi radian in 360 degrees. Tire inflated diameter can be determined by measuring circumference with a tape measure and computing the radius, or you can use half the diameter specified in the manufacturer's specs for the specific installed tire.

Duke

[John H.]

Re: C2 rear alignment questions

When last aligned 4 years and 7000 miles ago the shop added trailing arm shims ( new slotted style provided by me) and car was in spec RR @ -0.3 deg and LR @ -0.7 deg.

Randy -

The trailing arm shims affect only toe-in; they're unrelated to camber. Camber is adjusted via the cam bolts at the inboard end of the strut rods, and can go out of spec as a result of a loose cam bolt, deteriorated bushings at the ends of the strut rod, or excessive wear at the pinion shaft end of the diff side yokes.

[Michael H.]

Re: C2 rear alignment questions

Basic tenet of Euclidean geometry:

The arc length subtended by a small angle (which is essentially the same as the chord, which is the toe measurment) is equal to the angle in radians times the radius.

In terms of toe in this means:

Toe (per wheel) = toe angle (per wheel) in radians x tire inflated radius.

There are 2Pi radian in 360 degrees. Tire inflated diameter can be determined by measuring circumference with a tape measure and computing the radius, or you can use half the diameter specified in the manufacturer's specs for the specific installed tire.

Duke

Huh ? What'd he say ?

[Duke W.]

Re: C2 rear alignment questions

Most of us should have learned the above in high school.

Duke

[Lawrence M.]

Re: C2 rear alignment questions

If I had paid attention in High School I may have wond up driving a Corvette instead of a tank after graduation.

[Michael F.]

Re: C2 rear alignment questions

I went to school in arkansas and never learned no such thing

[Bob R.]

Re: C2 rear alignment questions

Duke,
High school was 50 years ago

[Randy S.]

Re: C2 rear alignment questions

Randy -

and can go out of spec as a result of a loose cam bolt, deteriorated bushings at the ends of the strut rod, or excessive wear at the pinion shaft end of the diff side yokes.

John et al,

How would I check for excessive wear at the pinion shaft end of the differential side yoke? As I said before I could feel no looseness in the wheel when it was jacked up. Will there be "slop" at the yoke/universal joint near the differential?

Randy