Thread: Custom alighnment

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I'm going to align a customer's 56 GMC 1/2 ton. It has the original straight axle, an aftermarket steering gear and P/S. Currently the caster is 1.5* positive and the vehicle wanders pretty severely. I'm thinking of wedging that up to about 4.5* positive. Any thoughts?

Shouldn't caster on a straight axle be negative (kingpin tilted to the rear)? Or have I got my +/- backwards?

Henry.....

Sometimes the axle has a tapered shim to set the caster. Due to either drink or inattention, the shims go in backwards, making the kingpins lean forward at the top......the vehicle is really squirrelly and wanders more than a retiree with a motor home. Early Fords have something like 6 deg + caster and yes, tilting the top back is in the + direction.

Glodenrog, Check to see if it has the wedges....bet they are backwards.

mike

Hey robot, would that possibley be a case of been there done that??? (Add me to the list, by the way!!!) (And I was sober)

Dave,
One time someone that I know personally (very), put an axle in with the shims backwards so that the kingpins tilted forward at the top. Then, that person drove 1000 miles in one trip. The vehicle would change lanes on its own, it was a real chore to keep it in the lane on a two lane road. I er....he drove the trip without stoping. It was a real chore. After the 1000 miles, the caster problem was discovered..... quick fix, long-lasting lesson.

mike

Originally posted by goldenrog
I'm going to align a customer's 56 GMC 1/2 ton. It has the original straight axle, an aftermarket steering gear and P/S. Currently the caster is 1.5* positive and the vehicle wanders pretty severely. I'm thinking of wedging that up to about 4.5* positive. Any thoughts?

I believe you are on the right track goldenrog.
with the caster set correctly, a car will wonder towards the ditch on a ball road, so what do you do to the caster to make the car go straight on a ball road? set this way it would wonder left on a flat road.