DIY: Low cost method to measure rear caster
07-03-2016, 03:12 PM
#1
Racer
Thread Starter
DIY: Low cost method to measure rear caster
As you are aware, for the first time the rear caster is adjustable on C7 Corvettes. I wanted to know what mine was set to. Local dealers were clueless as to how to check it or adjust it. Research on this forum revealed that the required adapter is available from GMtoolsandequipment.com (P/N CH-47960-10) for $182. Their recommended Digital Angle Gauge (P/N CH-47960) was cost prohibitive (something north of $600).
However, you don’t need the adapter to just measure the caster angle. This can be done using (a) 1.5” long ¼” diameter steel pins cut from 3 foot steel rod (available at Home Depot/Lowes), (b) a flat strip of steel such as a ruler and (c) a magnetic digital angle gauge, preferable back-lit for easy reading. I got one from Amazon for about $33.
The pictures below show how to measure using the steel pins. This method provided good accuracy. By the way, I tested the accuracy of the digital gauge on our granite inspection table and certified inspection blocks. It was SPOT ON! I was amazed.
This pin method provides accuracy, equivalent to using the adapter tool. Using the adapter tool just makes it easier to adjust the caster, i.e. – hands-free. I decided to make my own adapter and use a magnetic-style digital gauge. See pictures below.
Factory rear caster spec is 0.0 +/- 0.8 degrees. Mine measured, left side 89.80 = .20 positive caster; right side 89.85 = .15 positive caster. A friend’s Z51 measured almost the same.
I plan to offer the adapter tool for sale and will post pricing when they are available.
However, you don’t need the adapter to just measure the caster angle. This can be done using (a) 1.5” long ¼” diameter steel pins cut from 3 foot steel rod (available at Home Depot/Lowes), (b) a flat strip of steel such as a ruler and (c) a magnetic digital angle gauge, preferable back-lit for easy reading. I got one from Amazon for about $33.
The pictures below show how to measure using the steel pins. This method provided good accuracy. By the way, I tested the accuracy of the digital gauge on our granite inspection table and certified inspection blocks. It was SPOT ON! I was amazed.
This pin method provides accuracy, equivalent to using the adapter tool. Using the adapter tool just makes it easier to adjust the caster, i.e. – hands-free. I decided to make my own adapter and use a magnetic-style digital gauge. See pictures below.
Factory rear caster spec is 0.0 +/- 0.8 degrees. Mine measured, left side 89.80 = .20 positive caster; right side 89.85 = .15 positive caster. A friend’s Z51 measured almost the same.
I plan to offer the adapter tool for sale and will post pricing when they are available.
Last edited by Rickmd; 07-03-2016 at 03:16 PM. Reason: adding more pictures
The following 5 users liked this post by Rickmd:
16SSA8 (06-01-2018),
cjatrains (04-24-2021),
daleong (07-03-2016),
Jet Vet (07-03-2016),
McCarthy1986 (04-11-2022)
07-03-2016, 03:25 PM
#2
Racer
Thread Starter
This was my first attempt to post photos. Sorry. It didn't work too well. Don't know why they are sideways. Also the description /explanation of each photo didn't transfer.
07-03-2016, 04:49 PM
#3
Pro
Member Since: Jun 2015
Location: New Orleans LA
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St. Jude Donor '15-'16
Thanks for all the effort that went into this project. The pictures look fine to me, and if you have trouble spatially orienting yourself to understand what you are looking at in them you probably shouldn't be fooling with rear caster anyway! 
I track my Z51 regularly and I'm going straight to my speed shop tuesday to add this inspection & adjustment to his list.
JV
I track my Z51 regularly and I'm going straight to my speed shop tuesday to add this inspection & adjustment to his list.
JV
Last edited by Jet Vet; 07-03-2016 at 04:51 PM.