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.

 

if you know the from the flat area on the axle housing is 2 degrees off (which way?) then you can still use that for measuring, you just have to do a little simple math, right?

 

I would think that the problem with that is that the center housing is a casting and the angle could vary from one housing to the next so it might be 2 degrees or it could be more or less and negative or positive inclination.

Easiest thing to make sure it's right is to just yank out the pinion flange to driveshaft flange bolts and slide the shaft forward and use the pinion flange to measure from.

 

post pictures of the proper procedure.

 

You could take the two degrees into account, but the finish/smoothness/accuracy of the case has some tolerance and should be avoided, if possible. For rough measurements if you are using the bottom of the case you simply need to add two degrees to your measurement. The image below illustrates what is going on for clearer explanation.

 

me thinks Gus likes SolidWorks

 

 

LOL, not me, that's one of my engineers...