Snapon Caster gauge

[WZ JUNK]

Does anyone have the instructions or some knowledge of how to use this gauge to set caster?  I found instruction for a similar gauge but not for this one and I want to be sure that I get that right information.

John

[Crosley.In.AZ]

Seems like you turn the tire to 20* ( right tire to right , left to the left , one tyre at a time).


Reset the gauge to zero when tyre is turned........ then straighten the tire back to straight forward, and read the caster.  Then adjust accordingly.

tomslik does this stuff all day at Pep Boys...


YMMV.....


 

[Bob Paulin]

If you can tell me where the positive end of the CASTER scale is located - closer to the wheel or furthest from the wheel - I'll tell you how to use it.

That's the major difference between different guages......

[WZ JUNK]

If you can tell me where the positive end of the CASTER scale is located - closer to the wheel or furthest from the wheel - I'll tell you how to use it.

That's the major difference between different guages......

Sorry I did not get back to you sooner.  I have been drag racing all day and I made the post this morning right before I left.  In the morning I will take a picture of the gauge itself so you can have a look at what I have.  Thanks.

John

[WZ JUNK]

If you can tell me where the positive end of the CASTER scale is located - closer to the wheel or furthest from the wheel - I'll tell you how to use it.

That's the major difference between different guages......

Here is the picture.  I hope you can read the gauge.

[WZ JUNK]

I noticed after the post that the picture has a lot of glare in it.  I could take another if need be.  If you enlarge the picture by clicking on it, and strain your eyes, I think you can read the engravings on the gauge.

John

[Bob Paulin]

From what I can see, it appears that the negative end of the caster scale is closest to the wheel, so that would put the positive end furthest away from the wheel.....

So, with this particular guage....

First you turn the front of the wheel outward 20° from straight ahead.....

Reset the caster scale to zero....

Then turn the front of the wheel inward 20° from straight ahead.....

Read your caster scale.

The scale on the end of the guage that reads "Caster Correction" comes in handy when you are standing up on the front-end machine with your head under the hood - or tucked up inside the fender - adjusting the caster.

If you are careful to not move the guage while installing/removing shims, turning eccentrics, or sliding the upper comntrol arm mounts, it will show you approximately how much you are changing the caster without having to go through the wheel turning process.

Of course, once you have done the adjustments, you must take another caster reading.....turning the wheel out first, then in.

BTW - for those whose guages have the positive end of the caster scale closest to the wheel, you simply turn the front of the wheel IN 20° first, ste the caster scale to zero, then out 20° to take the reading.

Also, while this particular Snap-On guage doesn't have this feature, many of the newer alignment guages - especially those intended for racers - have the outer corners cut at an angle.

This angle is, usually, 20° so, if you turn the wheel so the flat corner of the guage is facing you and is parallel with the car's wheelbase, you will be at 20°.....eliminating the need for graduated turntables.

One final tip.....

You MUST have the wheels locked up with a pogo-stick on the brake pedal or something similar when checking caster.

If the front wheel rolls - even the slightest bit - it will give you a false caster reading.

A lot of times it will give you inconsistent readings - causing an increase in blood pressure, the loss of hair, etc.


B.P.

[WZ JUNK]

Thanks Bob.  That is how I thought it worked but I was not sure.  It seems to me that it is reading the total amount in the sweep from 20 degrees one way to 20 degrees the other direction.

John