Caster Angle Determination
- With vehicle on level surface, determine frame angle using bubble protractor or inclinometer. Determine caster angle reading from the alignment equipment.
- To determine an actual (corrected) caster angle with various frame angles and caster angle readings from the alignment equipment, one of the following rules applies:
- A "down in rear" frame angle must be subtracted from a positive caster angle reading. See Fig 1 , Example A.
- An "up in rear" frame angle must be added to positive caster angle reading. See Fig 1 , Example B.
- A "down in rear" frame angle must be added to a negative caster angle reading. See Fig 1 , Example C.
- An "up in rear" frame angle must be subtracted from a negative caster angle reading. See Fig 1 , Example D.
- The dimension "BC" is measured 90° from lower surface of crossmember to inboard rear corner of jounce bumper bracket. See Fig 1 , View A. Using dimension "BC" and appropriate ALIGNMENT SPECIFICATIONS table, find the recommended caster angle.
- If an actual (corrected) caster angle (step 2) does not correspond to a recommended caster angle (step 3) within F1°, make necessary shim changes to bring actual (corrected) caster angle in line with recommended caster angle.