P/S - Reduced Assist When Cold, New O Rings
Number: 92-333-3BSection: 3B
Date: DEC. 1992
Corporate Bulletin No.: 263202R
ASE No.: A4
Subject:
REDUCED POWER STEERING ASSIST WHEN COLD
Model and Year:
1988-92 C/K TRUCKS
Owners of some 1988-92 C/K trucks equipped with power steering may comment that during a cold start condition there is reduced power steering assist.
This condition is caused by the current fluoroelastomer O-rings not providing enough spring force to engage the teflon valve rings under all dimensional stack conditions. This condition occurs during vehicle cold starts, after the vehicle has been subjected to high temperature operating conditions.
To correct this condition, the steering gear valve assembly should be replaced with a new valve assembly that features new hydrogenated nitrile base rubber valve body O-rings to eliminate potential for lack of power steering assist during cold starts. The 1993 C/K production steering gears include the new valve assembly.
SERVICE PROCEDURE:
Tools Required :
J7624 Adjustable Spanner Wrench
J4245 Snap Ring Pliers
J8524-1 Adjuster Plug Bearing Installer
J7079-2 Driver
J2981 0 Seal Protector
J7754-01 0-25 lbs.in. torque wrench
REMOVE (Figure 1)
1. Steering gear from the vehicle.
- Refer to section 3B1 of the appropriate C/K service manual for complete removal instructions.
2. Adjuster plug locknut (245).
3. Adjuster plug assembly (240) using J 7624.
- Retaining ring (244) using J 4245 or equivalent snap ring pliers.
- Washer (243).
- Stub shaft oil seal (242).
- Adjuster plug seal (239)
4. Steering valve assembly (250) and stub shaft o-ring seal (249).
IMPORTANT:
Do not remove the worm shaft (248) and thrust bearing assembly (246, 247) when removing the steering valve assembly. Removing the worm shaft will result in one or more balls (213) dropping out of the steering worm circuit. Loss of any balls in the circuit will require a complete rebuilding of the steering rack and worm assembly.
INSTALL (Figure 1)
1. New stub shaft o-ring seal (249).
IMPORTANT:
The valve body assembly, rings and all seals should be lubricated with power steering fluid before assembly.
2. New steering valve assembly (250) (Figure 2).
IMPORTANT:
Note that pin (A) on the worm gear (248) lines up with slot (B) in the steering valve assembly (250)
3. Stub shaft oil seal (242) to adjuster plug (240) using J 8524-1 and J 7079-2.
- Be sure adjuster plug bearing (241) is seated in adjuster plug (240). Use J 8524-1 and J 7079-2 if necessary.
4. New adjuster plug seal (239) to the adjuster plug assembly (240).
5. Adjuster plug assembly (240) using J 7624.
- Protect the stub shaft oil seal (242) from damage by placing J 29810 over the splined end of stub shaft (251) before installing the adjuster plug (240).
- Adjust thrust bearing preload (Figure 3).
- After adjusting thrust bearing preload, check the turning torque of the stub shaft (251) using J 7754-01 (0-25 lbs.in. torque wrench) and a 12-point socket. Combined torque reading (stub shaft bearing preload and pitman shaft preload) for the gear assembly must not exceed 20 lbs.in. (2.26 N-m). If this reading is exceeded, repeat the adjustment procedure. If necessary, refer to section 3B1A-4 (Unit Repair Manual) for pitman shaft preload. Adjustment of 5-10 lbs.in. (0.57-1.13 N-m.) is desired. If this reading is not obtained, repeat the adjustment procedure.
6. Washer (243).
7. Retaining ring (244).
IMPORTANT:
The retainer projections must not extend beyond the washer (243) when the retaining ring (244) is seated. The washer must be free to rotate.
8. Adjuster plug locknut (245).
9. Steering gear to vehicle.
- Refer to section 3B1 of the appropriate C/K service manual for complete installation and system bleed procedure instructions.
SERVICE PARTS INFORMATION
Parts are currently available from GMSPO.
WARRANTY INFORMATION
For vehicles repaired under warranty use:
Labor Operation Model Labor Time
T7176 C 1.2 hrs.
T7176 K 1.3 hrs.
Use applicable labor time guide for labor hours.
NOTE:
Labor Operation is coded to base vehicle coverage in the warranty system.