Strange Things Happen...

[The Critic]

Last month, I took my friend's 2006 Prius to a Pep Boys for four Cooper CS4 Tourings and an alignment.

After the alignment, I noticed that the steering wheel was not centered and the car still drifted to the right on the highway. Here were the alignment specs at that time:

Front:

LF Toe: 0.00
RF Toe: 0.05

LF Camber: -0.4
RF Camber: -1.4

Rear:

LR Toe: 0.05
RR Toe: 0.10

LR Camber: -1.2
RR Camber: -1.7

So, I knew I needed to take the car back since the steering wheel was off-center (due to tech error). But according to the results, the RF camber needed some correction as well. So, I purchased a Moog "Fast Cam" bolt, which features 1 degree of +/- correction.

Fast forward to today. I removed the RF upper strut mounting bolt and replaced it with the Moog "fast cam" bolt. I fiddled with the bolt until the washer and bolt head seated flush with the strut. When I was finished, the the washer handle was pointed towards the outside of the car, as was the the "-" imprint on the bolt head (IIRC, this means the lobe was opposite the washer handle). I did not touch the lower bolt aside from checking that it was properly tightened.

My friend and I took the car for a drive down the Hwy 17 and the car suddenly tracked straight. It no longer drifted to the right! Normally, when you install a camber bolt, you are supposed to loosen both strut mounting bolts, then turn the camber bolt in order to get any adjustment. But I didn't do anything besides installing the camber bolt, as I was planning to drive it straight to the shop to have it aligned anyway.

At the shop, they mounted the car back on the rack and took measurements. Now, the LF camber was reading -0.7 degrees and the RF camber was reading -0.9 degrees-- which is right in the middle of the allowable range. The tech went ahead and reset the RF toe to 0.00 degrees (from 0.05 degrees), and sent me on my way. (The LF toe was still at 0.00, so he didn't touch that.) On the drive home, my friend was able to drive at 70mph for minutes at a time without holding the steering wheel-- the car stayed straight!

So, what do you guys think happened? I didn't actually "turn" the camber bolt to perform any form of adjustment, yet the camber problem magically cured itself. Could the chamber have changed simply from the action of removing/reinstalling the upper strut mounting bolt?

[Patrick Wong]

Originally Posted by The Critic

... Could the chamber have changed simply from the action of removing/reinstalling the upper strut mounting bolt?

Yes, this is what apparently happened. A happy ending, so no worries.

[dogfriend]

The difference between -1.4 and -0.9 is not very much in terms of movement of the strut. Also, from the multiple times that I had my car checked when I was trying to get the rear alignment fixed, it seems like there is about a 0.1 degree of uncertainty between measurements, even with the same tech using the same equipment.

[KK6PD]

Well, as we say in the maintenance world,"If it works, don't fix it!"

Nice job on the diagnosis, and the repair. Sometimes, you just get lucky, ENJOY IT!!!