NTBA

The NTBA TECH pages

Typically, when your T is turning sharper one way than the other your steering geometry is out of kilter. It is usually easily remidied by re-centering the components that make up the geometry.

1) output shaft in the steering box

2) Pitman arm connected to steering box

3) Steering rod connecting the pitman to the steering arm

First, roll your T and make sure it is tracking straight then disconnect the steering rod from the pitman arm. Now, spin yor steering wheel all the way one direction until it stops. Rotate the wheel opposite direction keeping count of the number of revolutions until it stops. Divide the count in half, and rotate the steering wheel to the center. Look at your pitman arm. It should be straight up & down. Meaning, the center line of the

pitman.gif (8102 bytes)

steering box shaft is vertical to the center line hole where the steering rod connects. If the pitman are is angled towards the rear of your vehicle, you will get more LEFT steering, and if it is towards the front of your vehicle you get more RIGHT steering. Disconnect the pitman arm and reposition it to sit straight up & down, as per the illustration. now adjust the length of your steering rod to fit in the pitman without moving your wheels. This will center your pitman to the wheels and set the proper length of the steering arm. With everything connected, lift your front end and rotate the wheels left and right. Check the travel in both directions.

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There is another alignment which effects your steering but also induces "bump steering". This can be more difficult to correct. Looking from the side of your vehicle, is the steering rod level to the pitman and the steering arm? If not, you have "bump steer". There should be a 90 degree angle between the centerline of the pitman and the centerline of the steering arm. If it isn't, your chasis was poorly designed, and will be fairly difficult to correct. SEE: illustration below

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To correct this, you will have to either shorten/lenghten the pitman arm or raise/lower the steering arm to get it level. Or, move your steering box up/down to get the proper alignment. You will need to study your linkage setup closely and determine the best method to correct the problem. There are several pitman arm lengths available for the Corvair box. And it could be an easy fix for you. You may look at where the steering rod connects to the steering arm. Sometimes you can reverse the connection IE: move from top to bottom. This can give you another 3/4" adjustment or more.

It is important to keep "bump steer" to a minimum. Only the left front wheel can induce "bump steer" because it is where the steering rod connects. The right front is connected by the tierod.

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When your left wheel moves up, in induces right bump steer. And when your left wheel goes down, it induces left bump steer. The interesting thing is, you get more bump steer to the LEFT than to the right! The reason for this is, when the actual center line of the steering arm approaches the "correct" theoretical center line, the pushing effect is amplified.