I was having this conversation with one of my tech's today and I thought it would be great to post here to help others.
We were discussing how you can make a mistake measuring pinion angle on the S197 axle assembly. The S197 axle housing has a large flat beneath the pinion snout. That flat would be a very convenient place to measure the pinion angle from since an inclinometer can easily be rested on it.
The problem is that flat is not parallel to the pinion flange angle. It is actually two degrees off. As you can imagine, measuring pinion angle from this flat and not knowing there is a two degree difference in it would always result in a pinion angle that is two degrees from the intended angle. The correct, and only way, to properly measure pinion angle would be from the actual flange on the pinion. It is more difficult to measure from the pinion flange (in comparison to the flat on the housing) but unless you do it at the pinion flange you would be off by 2 degrees.
So moral of the story, stick to measuring from the pinion flange when measuring your pinion angle on S197 cars.
We were discussing how you can make a mistake measuring pinion angle on the S197 axle assembly. The S197 axle housing has a large flat beneath the pinion snout. That flat would be a very convenient place to measure the pinion angle from since an inclinometer can easily be rested on it.
The problem is that flat is not parallel to the pinion flange angle. It is actually two degrees off. As you can imagine, measuring pinion angle from this flat and not knowing there is a two degree difference in it would always result in a pinion angle that is two degrees from the intended angle. The correct, and only way, to properly measure pinion angle would be from the actual flange on the pinion. It is more difficult to measure from the pinion flange (in comparison to the flat on the housing) but unless you do it at the pinion flange you would be off by 2 degrees.
So moral of the story, stick to measuring from the pinion flange when measuring your pinion angle on S197 cars.