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Control Arm Adjustment. Control Arm Movement Concepts Inboard shim adjustment Outboard shim adjustment Slotted frame / Eccentric cam Symmetrical lower arm adjustment Asymmetrical Upper and Lower control arm adjustment . Positive Camber Change (Symmetrical Upper Control Arm).
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Control Arm Adjustment • Control Arm Movement Concepts • Inboard shim adjustment • Outboard shim adjustment • Slotted frame / Eccentric cam • Symmetrical lower arm adjustment • Asymmetrical Upper and Lower control arm adjustment
Positive Camber Change (Symmetrical Upper Control Arm) • Move front and rear of upper control arm outward equal amounts • 1/16” equals 1/4° • 1/8” equals 1/2° • 1/4” equals 1 degree Front
Negative Camber Change (Symmetrical Upper Control Arm) • Move front and rear of upper control arm inward equal amounts • 1/16” equals 1/4° • 1/8” equals 1/2° • 1/4” equals 1 degree Front
Positive Caster Change (Symmetrical Upper Control Arm) • Move the front of the control arm outward and the rear of the control arm inward equal amounts • 1/32” equals 1/2 degree • 1/16” equals 1 degree • 1/8” equals 2° Front
Negative Caster Change (Symmetrical Upper Control Arm) • Move the front of the control arm inward and the rear of the control arm outward equal amounts • 1/32” equals 1/2° • 1/16” equals 1° • 1/8” equals 2° Front
Positive Camber & Caster (Symmetrical Upper Control Arm) • Move the front of the control arm outward • 1/16” equals 1/2° caster & 1/4° camber • 1/8” equals 1° caster & 1/2° camber Front
Negative Camber & Caster (Symmetrical Upper Control Arm) • Move the front of the control arm inward • 1/16” equals 1/2° caster & 1/4° camber • 1/8” equals 1° caster & 1/2° camber Front
Positive Camber & Negative Caster (Symmetrical Upper Control Arm) • Move the rear of the control arm outward • 1/16” equals 1/2° caster & 1/4° camber • 1/8” equals 1° caster & 1/2° camber Front
Negative Camber & Positive Caster (Symmetrical Upper Control Arm) • Move the rear of the control arm inward • 1/16” equals 1/2° caster & 1/4° camber • 1/8” equals 1° caster & 1/2° camber Front Menu
Inboard Shims Front Menu
Camber Increase • Remove equal thickness shim from front and rear • 1/16” = 1/4° • 1/8” = 1/2° • 1/4” = 1° Front Remove Remove Shims
Camber Decrease • Add equal thickness shim from front and rear • 1/16” = 1/4° • 1/8” = 1/2° • 1/4” = 1° Front Add Add Shims
Caster Increase • Remove shim from front and add to rear • 1/32” = 1/2° • 1/16” = 1° • 1/8” = 2° Front Move Shims
Decrease Caster • Remove shim from rear and add to front • 1/32” = 1/2° • 1/16” = 1° • 1/8” = 2° Front Move Shims Menu
Outboard Shim (symmetrical) • Reverse the shim movement shown for Inboard Shims • All other factors stay the same • 1/16” equals 1/4° camber • 1/16” equals 1/2° caster Menu
Slotted Frame Adjustment • Upper Control Arm • Changes Camber and/or Caster • Methods: • Hit and Miss • Slotted Formula Menu
Eccentric Cam Adjustment • Upper Control Arm • Changes Camber and/or Caster • Methods: • Same as slotted control arm • More controllable Menu
Ford / Lincoln/ Mercury • Eccentric Adjusters for front camber and caster. • Loosen lock nut and rotate large lower nut to adjust angles. Menu
Reduce specification tolerances to: .25° (1/4) camber tolerance .50° (1/2) caster tolerance Lock the service brakes Level and lock the front sensors View the front bar graph screen for front camber and caster Slotted Control Arm Formula
Camber and Caster Adjustment • Is the null indicator equal distance from center on both bar graphs? • NO - Requires two moves • YES - Requires one move
Null indicators are not equal • Which end of the control arm must move to make both null indicators move toward the center of their respective graphs? • Camber (+) & Caster (+) - front moves out • Camber (-) & Caster (-) - front moves in • Camber (-) / Caster (+) - rear moves in • Camber(+) / Caster (-) - rear moves out
Null indicators are not equal • Move the control arm until both null indicators are equal distance from the center of their respective graphs.
Null indicators are equal • Move the end of the control arm which will make both null indicators move toward the center of their respective graphs.
Symmetrical Lower Control Arm • Reverse the upper control arm movements • All other factors stay the same • 1/16” equals 1/4° camber • 1/16” equals 1/2° caster Menu
Asymmetrical Control Arm Adjustment • The adjuster furthest from the ball joint will: • have the greatest effect on caster • have the least effect on camber Menu
Add or remove shims equally to change camber Add or remove shims from the pack furthest from the ball joint to adjust caster Asymmetric Upper Control Arms GM G20 Van
Asymmetrical Lower Control Arm • Rotate the eccentric closest to the ball joint to adjust camber • Rotate the eccentric furthest from the ball joint to adjust caster Menu
Common Adjustments Front Suspension Lower control arm Lower strut Upper Strut plate Ball joint Strut rod Bushing or threaded insert Rear Adjustments Common Rear Adjustments Menu
Slotted Lower Control Arm 93 F body
Lower Strut Attachment • Lower attachment bolts may permit camber angle adjustment. • Aftermarket kit may be required.
Upper Strut Plate • Camber and/or caster may be adjusted by repositioning the upper strut mount • Aftermarket kit may be required
Ball Joint • A ball joint may be rotated or repositioned to adjust camber and / or caster.
Strut Rod • Loosen one nut and tighten the other to adjust caster • Washers may also be used
Bushing or Threaded Insert • Camber and / or caster may be adjusted by rotating or replacing the insert bushing. Menu
Typical Rear Adjustments Full Contact Shim Eccentric Cam Tie Rod Lower Strut Slotted Control Arm Wedge Strut Rod Menu
Full Contact Shim • Adjust Rear Camber and Toe using full contact shims • Hunter • Northstar • Specialty
Eccentric Cams • Eccentric cams may be used to adjust rear toe and /or camber
Tie Rods • Adjust rear individual toe using tie rod adjustment
Lower Strut • Rear camber may be adjusted by loosening the lower strut retaining bolts and pulling inward or outward
Slotted Control Arm • Rear lower control arms may be slotted to permit toe and camber adjustments
Wedge • A “wedge” be used to adjust rear camber • Wedges may also be used to adjust front camber
Strut Rod • A rear strut rod may be used to adjust individual rear toe
What Are Equipment Manufacturers Doing To Help Technicians Adjust Various Control Arm Configurations Faster And Better? • A vehicle specific software tool has been developed for vehicles with control arms using shims, cams and slots.
How to turn red bar graphs green fast is the problem – adjust with shims
Corvette with symmetrical A arm - shims outboard of frame – actual shim size
Caprice with symmetrical A arm - shims inboard of frame – actual shim size
Chevy C10 with asymmetrical A arm - shims outboard of frame – actual shim size
Chevy C10 with asymmetrical A arm - shims outboard of frame – actual shim size
Technician time saver – adjust one side only to match the other side
How to turn red bar graphs green fast is the problem – adjust with eccentric cams