My 97 4 banger has a 3 inch lift, 1 inch motor mount lift, and a 1 inch body mount lift. Stock transfer case and drive shaft. I have adjustable upper and lower control arms on both the front and rear, as well as adjustable track bars. Also front caster cam delete plates.
I finally got around to adjusting my control arms after installing the lift, and I followed the write up from another site that had me pull the springs and center the bump stops with the spring perch at full bump, then set lowers, then adjust pinion angle etc. for the uppers.
First thing I noticed after reinstalling the tires and dropping the vehicle to the floor was that my front wheels looked too far forward, nearly maxing out the adjustability in the control arms, and in the rear the tires seemed also too far forward, with the control arm adjustments basically bottomed out.
I am pretty sure I set the rear pinion angle correctly, parallel to the transfer case output shaft at 3.2 degrees.
But I am pretty sure I screwed up the front pinon. I read that there is a 12 degree difference between pinion and caster for the LP30. I put my angle finder on the doughnut on the back of the differential, cranked the pinion up to 18 degrees, then subtracting 12, gives me 6 degrees of caster which was my target for 33 inch tires. But I have seen some other math on a few sites that say if you are shooting for 6 degrees, then you go 6 degrees on your pinion, then subtract 12 and you get negative 6, which is actually a positive caster of 6. Which this would mean I currently have 6 degrees of negative caster currently the way I adjusted to 18 degrees. Math is hard.
Needless to say, I am going to do it all over again while the correct size sockets are still scattered around the floor of my garage. But I need some assistance with the caster angle math. My plan was to start at 6 degrees of caster and hope for no vibrations and good drivability. Then adjust up or down to get the best caster angle with no vibrations.
By the way, is it obvious when the vibrations are coming from the front and not the rear driveshaft? I have this nightmare of chasing my tail.
I've been working on this thing for 5 years.
Thank you.
I finally got around to adjusting my control arms after installing the lift, and I followed the write up from another site that had me pull the springs and center the bump stops with the spring perch at full bump, then set lowers, then adjust pinion angle etc. for the uppers.
First thing I noticed after reinstalling the tires and dropping the vehicle to the floor was that my front wheels looked too far forward, nearly maxing out the adjustability in the control arms, and in the rear the tires seemed also too far forward, with the control arm adjustments basically bottomed out.
I am pretty sure I set the rear pinion angle correctly, parallel to the transfer case output shaft at 3.2 degrees.
But I am pretty sure I screwed up the front pinon. I read that there is a 12 degree difference between pinion and caster for the LP30. I put my angle finder on the doughnut on the back of the differential, cranked the pinion up to 18 degrees, then subtracting 12, gives me 6 degrees of caster which was my target for 33 inch tires. But I have seen some other math on a few sites that say if you are shooting for 6 degrees, then you go 6 degrees on your pinion, then subtract 12 and you get negative 6, which is actually a positive caster of 6. Which this would mean I currently have 6 degrees of negative caster currently the way I adjusted to 18 degrees. Math is hard.
Needless to say, I am going to do it all over again while the correct size sockets are still scattered around the floor of my garage. But I need some assistance with the caster angle math. My plan was to start at 6 degrees of caster and hope for no vibrations and good drivability. Then adjust up or down to get the best caster angle with no vibrations.
By the way, is it obvious when the vibrations are coming from the front and not the rear driveshaft? I have this nightmare of chasing my tail.
I've been working on this thing for 5 years.
Thank you.
