Poor tracking (crabbing)

[alfourfire]

I was told today by another car following me to a car show that my 66 T-bird was not tracking straight and called it "crabbing" which makes sense. Could this be a misalignment of the rear axle? I thought I had a 4-wheel alignment a few years ago but I may be missing something. Any suggestions? Rick

[keiser31]

Sounds exactly like rear axle misalignment. Measure the wheelbase on each side and see if they are different.

[Larry Schramm]

Another term for what you describe is dog tracking. It is caused by the thrust angle of the rear axle off.

Here is a good utube of the condition.

[TexRiv_63]

A 66 Thunderbird has a solid axle in the rear and to my knowledge has no adjustment possible in the back, so a 4-wheel alignment is not possible. Any misalignment severe enough to cause visible dog tracking would be caused by damage to either the axle mounting points or the unibody structure of the vehicle. Has the car ever been in a major wreck?

[nickelroadster]

I don't believe that a 66 Thunderbird was a unibody vehicle but perimeter frames can also be bent. Check the wheelbase carefully and look for damage both front and rear.

[alfourfire]

I don't believe the car was damaged in the past. I did change the rear leaf springs 2 years ago. I thought I set the axle properly, but checking it today there is aprox. 1 inch difference between wheel measurements by tape. I will put it on the lift and check further. Thanks, Rick

[countrytravler]

You probably didn't re tighten the u bolts after putting a couple hundred miles on it. Possible axle shift because of a loose u bolt.

[keiser31]

You probably didn't re tighten the u bolts after putting a couple hundred miles on it. Possible axle shift because of a loose u bolt.

That is what I meant by misalignment. Thanks Dave.