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Help measuring caster

gearhead22

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Hello all. Currently in the process of installing a MC 3.5” kit. I noticed that MC’s control arm measurements are a bit shorter than every other lift manufacturer so I ended up using Clayton’s length recommendations for their 3.5” kit.

I have the kit all back together but am wondering on how to accurately measure my caster. I’m aware of measuring the pinion flange (0 degrees equals 6 degrees of caster), the ball joints (looking for 6 degrees) and the front spreader holes on the diff housing (90 degrees equals 6 degrees caster).

my issue and questions are, are these measurements done at ride height? Can you check and set it prior to doing the rear portion of a lift? I only have the front installed at the moment. Also, what if the ground the vehicle is sitting on isn’t perfectly level, how can you get an accurate measurement?

right now, if I recall correctly (I’m inside now after calling it quits for the night) I’m getting 8 degrees on the front driveshaft, -2 degrees on the pinion, and 90 degrees on the spreader holes and I think around 10 degrees on the ball joints.

The truck is currently on jack stands, but they’re under the axle so it’s under its own weight. I am quite certain it’s lifted high in the front and leaning towards the back which I would think would skew the results.

how can I measure the caster and set it accurately?
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PuddleJumper

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vehicle must be sitting on it tires holding its own weight to properly measure caster.
 

PuddleJumper

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Why can’t it be on jack stands?
Yeah jack stands are fine if they are on the axles and not the frame. The important bit is the springs holding the truck weight. Also 6 degrees is nice but 4 is within spec and liveable. Don't give yourself a headache chasing a number. IF it says 5.2 or something, just send it.
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