Wheel Alignment Specifications & Procedures - R & V Series GMC Pickup R2500

RIDING HEIGHT

Ensure tires are correctly inflated, cargo compartment is empty and fuel tank is full. Bounce vehicle several times to normalize ride height.

Most vehicles provide front wheel alignment specifications which allow camber and cater adjustment for a large range of ride heights. Ride height for light trucks is listed as in the alignment tables. Ride height measurement points are shown. (Scheme 7)

Scheme 7

CAMBER

Camber is the inward or outward tilt of the wheel as viewed from front of vehicle. Camber is measured from centerline of vehicle. When wheel is tilted outward at top from centerline of vehicle, camber is positive. When wheel is tilted inward at top from centerline of vehicle, camber is negative. Camber is measured in degrees from vertical. Camber is designed into the front axle assembly of all four-wheel drive vehicles and is non-adjustable.

Scheme 8

CASTER

Caster is the tilting of front steering axis. This forward or backward tilt from vertical is viewed from side of vehicle. When axis is tilted backward from vertical, caster is said to be positive, creating a trailing action on front wheels. When axis is tilted forward, caster is negative, causing a leading action on front wheels.

Scheme 9

TOE

Toe is the measured difference in inches of distance between the front edge of the tires and the rear edge of the tires at spindle height. Toe can be measured in inches or degrees.

ADJUSTMENT

Front end alignment specifications should be set while vehicle is in its normally loaded condition.

ACCESS TO SHIM PACKS

On models with 3/4-inch nut, raise vehicle off the ground to allow the proper control arm to drop down far enough to use a socket on the nuts and permit shim adjustment. Torque nut to proper specifications. On models with 7/8 inch nut, remove the upper control arm bumper first, then follow above instructions.

CAMBER ADJUSTMENT

Note. For camber adjustment (Scheme 11)

Adjusting Camber & Caster. Scheme 10

Preliminary Information

All caster specifications are given with a frame angle of zero. To correctly read caster, the angle of the frame must be determined (whether "up" in rear or "down" in rear). (Scheme 11)

Determining Caster

1. Place vehicle on level surface.
2. Measure the frame angle using a bubble protractor or inclinometer. The frame angle is the degree of tilt in the frame from the level position.
3. Determine frame angle.
4. Determine caster angle reading from alignment equipment.
5. The following rules apply when determining actual caster reading: a) A "Down in rear" frame angle must be subtracted from a positive caster reading. b) An "Up in rear" frame angle must be added to a positive caster reading. c) A "Down in rear" frame angle must be added to a negative caster reading. d) An "Up in rear" frame angle must be subtracted from a negative caster reading.
6. Dimension "BC" measured 90 degrees from the lower surface of the crossmember and to the inboard rear corner of the jounce bumper bracket.
7. Using dimension "BC" and the caster, camber, wheel toe-in chart sheet, fine the proper caster angle.
8. If the present caster cycle is not within proper caster angle, make the necessary shim changes.

Measuring Ride Height. Scheme 11

TOE-IN

1. Determine toe-in.
2. Change the length of both tie rod sleeves to affect a toe change. Toe-in can be changed by increasing or decreasing the length of the tie rod ends. When the tie rod ends are mounted ahead of the steering knuckle they must be decreased in length in order to increase toe-in. When the tie rod ends are mounted behind the steering knuckle they must be lengthened in order to increase toe-in.

Adjusting Toe. Scheme 12

TOE-OUT ON TURNS

1. This is a check for bent or damaged parts, and not a service adjustment. With caster, camber and toe-in properly adjusted, check toe-out with weight of vehicle on wheels.
2. Use full-floating turn table under each wheel. Turn left wheel in 20 degrees on scale of turn table and read scale of turn table on right wheel. Reading should be within 2 degrees of left wheel. Repeat test for right wheel.
3. Incorrect readings of toe-out generally indicates a bent steering arm. Replace arm and recheck wheel alignment adjustments. DO NOT attempt to correct by straightening parts.

Wheel Toe-Out On Turns. Scheme 13

STEERING AXIS INCLINATION

1. This is a check for bent or damaged parts, and not a service adjustment. Vehicle must be level, both crosswise and lengthwise. Camber should be properly adjusted.
2. If camber cannot be brought within limits and steering axis inclination is correct, steering knuckle is bent. If camber and steering axis inclination are both incorrect by approximately the same amount, upper and lower control arms are bent.
3. Replace parts and recheck all wheel alignment adjustments. DO NOT attempt to correct by straightening parts.

Scheme 14

VEHICLE CHECKS

Prior to making wheel alignment adjustments, check and adjust the following items

1. Tire pressure must be inflated to manufacturer's recommended specifications.Tires should be equal in size and type. Runout must not be excessive. Tires and wheels should be in balance.
2. Wheel bearings must be properly adjusted. Steering linkage and suspension must not have excessive wear and/or looseness. Check for wear in tie rod ends and ball joints.
3. Steering gear box must not have excessive play. Check and adjust to manufacturer's specifications.
4. Vehicle must be at correct ride height with full fuel load and spare tire in vehicle. No extra load should be on vehicle.
5. Vehicle must be level with floor and with suspension settled. Jounce front and rear of vehicle several times and allow it to settle to normal ride height.
6. Ensure steering wheel spokes are centered with front wheels in straight-ahead position, correct by shortening one tie rod adjusting sleeve and lengthening opposite sleeve equal amounts.
7. Ensure wheel lug nuts are tightened to torque specifications.

R100 - 2WD

WHEEL ALIGNMENT SPECIFICATIONS (R100 - 2WD)

R200 & R300 - 2WD

WHEEL ALIGNMENT SPECIFICATIONS (R200 & R300 - 2WD)

V100, V200 & V300 - 4WD

WHEEL ALIGNMENT SPECIFICATIONS (V100, V200 & V300 - 4WD)

TORQUE SPECIFICATIONS

LUG NUT TORQUE SPECIFICATIONS