Upper Control Arm - GMC G Service Manual

UPPER CONTROL ARM

M Remove or Disconnect (Figures 5 through 13
Tool Required:
J 23742 Ball Joint Separator
• Raise the vehicle and support it with suitable safety
stands. Remove the wheel and tire assembly. Place
an adjustable jackstand under the lower control arm
for support.
1. Caliper.
• Refer to HYDRAULIC FOUNDATION BRAKES
(SEC. 5A2).
2. Cotter pin (15).
3. Upper control arm (28) from the steering knuckle (31).
• Loosen the nut (14), but do not remove it.
• Install J 23742 with the large cupped end over
the lower control arm ball joint stud nut (35).
Expand J 23742 until the upper control arm
separates.
• Nut (14) from the upper ball joint stud and raise
the upper control arm to clear the steering
knuckle.
4. Nuts (27), spacers (19), shims (18), washers (5) and
bolts (6).
f ] Important
• Tape the shims together in their original posi­
tions and tag for proper relocation.
5. Upper control arm (28) from the frame bracket (9).
M Install or Connect (Figures 5 through 13)
NOTICE: For steps 3 and 5, see " Notice" on page
3C-1 of this section.
1. Shims (18) into position on the upper control arm
frame bracket (9).
• Make sure the shims are positioned with con­
cave and convex sides together.
2. Upper control arm (28) to the frame bracket (9).
3. Spacers (19) and nuts (27), washers (5) and bolts (6).
r ] Important
• A normal shim pack will leave at least two
threads of the bolt (6) exposed beyond the nut.
FRONT SUSPENSION 3C-29
• If two threads cannot be obtained, check for
damaged control arm or related parts. The dif­
ference between the front and rear shim packs
must not exceed 7.62 mm (0.30 inches). The
front shim pack must be at least 6.09 mm (0.24
inches).
• Always tighten the thinner shim pack's nut (27)
first for improved shaft to frame clamping force
and torque retention.
R x l Tighten
• R10/1500, G10/1500 and G20/2500 models:
— Nuts (27) to 95 N-m (70 ft. lbs.).
• All other models:
— Nuts (27) to 142 N*m (105 ft. lbs.).
4. Upper control arm (28) to the steering knuckle (31).
• Insert the upper control arm ball joint stud (13)
into the steering knuckle (31).
5. Nut (14) and cotter pin (15).
Tighten
• R10/1500, G10/1500 and G20/2500 models:
— Nut (14) to 68 N«m (50 ft. lbs.).
• All other models:
— Nut (14) to 122 N*m (90 ft. lbs.).
• Tighten the nut if needed to install the cotter pin.
I { | Important
• R10/1500, G10/1500 and G20/2500 models:
— Maximum torque to align the cotter pin is
122 N»m (90 ft. lbs.).
• All other models:
— Maximum torque to align the cotter pin is
175 N-m (130 ft. lbs.).
6. Caliper.
• Refer to HYDRAULIC FOUNDATION BRAKES
(SEC. 5A2).
• Check the front end alignment and reset as required.
• Refer to FRONT END ALIGNMENT (SEC. 3A).
7. Wheel and tire assembly.
• Lower the vehicle.