Vehicle Pulls/Leads Left or Right (replace Strg Idler Arms/Reset Alignment)

Some owners may comment about an annoying pull to either side while applying the brakes.

To correct the above condition, perform the following: A). preliminary checks, B). alignment preparation, including replacing the steering idler arms with a new low lash idler kit, and C). reset alignment. Use the part number and service procedure listed below.

Notice: Do not overheat the brakes, as damage to the pads or rotors may occur. After a test, allow the brakes to cool before the next test.

1. Adjust the tire pressure to specifications.
2. Road test the vehicle in order to duplicate the condition. The pull usually occurs with warm brakes. Do this by making several mild low speed, 50-70 km/h (30-40 mph), stops and then make several more 80 km/h (50 mph) stops below the ABS threshold.
3. Cross switch the front tire and wheel assemblies.
4. Road test the vehicle. Does the vehicle pull in the same direction?

•	If the vehicle does not pull in the same direction, the probable cause is the tires.

•	If the vehicle does pull in the same direction, proceed to the next step.

5. Inspect the brake system.

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Verify the front brake clearance. Measure the clearances individually and add the clearances together for total clearance before removing the caliper. If the caliper (total clearance) to the steering knuckle stops is under 0.20 mm (0.008 in), correct this by filing metal off at the steering knuckle stops in order to obtain a total clearance of 0.26-0.60 mm (0.010-0.024 in). DO NOT FILE METAL OFF OF THE CALIPER.

•	Inspect all of the front brake components and replace only if necessary.

•	Verify the rear brake clearance/adjustment, including the park brake.

•	Inspect all the rear brake components and replace only if necessary.

1. Remove the frame bracket knockouts using the following steps:

•	Remove the tire and wheel assembly.

•	Note the position of the adjusting cams (lobes down) and the adjusting cam bolts.

•	Remove the upper control arm nuts and the adjusting cams.

•	Remove the upper control arm bolts and the adjusting cams.

•	Reposition the upper control arm in order to access the frame brackets.

•	Remove the frame bracket knockouts using a pry bar or knockout tool.

•	Clean up the slots and elongate the slots even past the ends (as the slots may not be in the center of the brackets and in order to obtain maximum adjustment).

•	Clean any weld that may prevent the cams from fully seating against the brackets.

•	Install the upper control arm to the frame brackets.

•	Install the adjusting cams with the lobes down.

•	Install the upper control bolts and nuts. Hand tighten only at this time.

•	Install the tire and wheel assembly.

•	Repeat for the opposite side.

2. Replace both of the steering idler arms with a low lash idler kit, P/N 12471302. Refer to the Steering Linkage subsection of the appropriate Service Manual.
3. Adjust the rear cams so that the upper control arms are all the way in. Then adjust the front cams so that the cams are all the way out.

Tighten
Tighten the cam nuts to 145 N·m (107 lb ft).

1. Loosen the lower control arm bolts, ensuring that the arms are free.
2. Adjust the vehicle trim "Z" height, one side at a time in small 1/2 turn increments, to 136-140 mm (5.375-5.5 in). Maintain the left front higher than the right. The reason for this is that the left front side is heavier than the right, and when the driver is added the left settles more.

Important: Leave the camber be whatever it comes out after adjusting caster. Because of the frame configuration, the left front camber will probably come out over 1 degree positive.

3. Adjust the caster. The objective is to have the highest caster possible. Leave both the rear cams full in and the right front full out in order to try and obtain a minimum of 5.5 degrees of right caster. Adjust the left caster to be 1.50 to 2.0 degrees less. For severe pulls, try to obtain the 2.0 degrees cross caster. The best procedure found is to leave the right side as is and adjust the left front cams only, whenever possible. Afterwards, a secondary adjustment is to adjust the right front.

Tighten
Tighten the cam nuts to 145 N·m (107 lb ft).

4. Adjust the front toe using the specifications below.

Important: The trim "Z" height measurement should not exceed 150 mm (5.9 in) or driveline vibration may occur.

5. Verify the vehicle trim "Z" height, keeping within the 136-140 mm (5.375-5.5 in) range.

Tighten
Tighten the lower control arm bolts to 133 N·m (98 lb ft).

6. Perform a caster sweep as another alignment adjustment may be necessary.
7. Lower the vehicle and bounce/rock the vehicle in order to settle it.
8. Perform a final toe set using the specifications below.
9. A final sweep for an alignment check may reveal the caster has decreased at the higher trim heights. Do not reset the alignment unless the caster split has been reduced. The higher trim height will produce lower casters. A greater caster split is better unless the vehicle leads to the left.
10. Road test the vehicle for the brake pull.
11. If the vehicle still pulls to the right, try and increase the cross caster by reducing the left caster.
12. If the vehicle still pulls to the left, reduce the cross caster.
13. If the above procedure fails to successfully reduce/eliminate the pull/lead sufficiently to satisfy the customer, further brake work may be required.

Parts are currently available from GMSPO.

For vehicles repaired under warranty, use: