C 2500 Truck 2WD V8-454 7.4L (1988)
Power Steering Pump: All Technical Service Bulletins
P/S - Whine Noise
GMC NUMBER:
88-T-174
GROUP. 3B-Steering
DATE:
October, 1988
CORPORATE
NUMBER:
863203
SUBJECT:
POWER STEERING WHINE
MODELS:
1988 C/K WITH POWER STEERING (RPO N41)
The power steering pump on some 1988 C/K trucks may whine on cold start. This can be caused by improper damping of the pump inlet hose to the inlet
tube. This condition can allow air to be pulled into the pump system. Low power steering fluid level may also contribute to the condition.
FIGURE 1 - POWER STEERING PUMP HOSE CONNECTIONS
Service Procedures (Figure No. 1)
To remedy the above condition, check the pump inlet hose damp for proper installation and the power steering fluid for proper level. Inspect and repair
condition as detailed below.
Inspecting Clamps and Hoses
Check Oetiker clamp (3) on the pump inlet hose assembly (2) for tightness. When the clamp is initially installed, some degree of spring back is normal.
The spring back should result in no more than a 1.5 mm (.06 in.) gap in the damp as shown in view "C" of Figure No. 1.
If gap is excessive, remove old clamp and install new clamp. New clamp and hose must be installed on tube to dimensions shown in view "C". Crimp
new clamp (3) down to zero gap and allow clamp to spring back. Check for 1.5 mm (.06 in.) maximum gap. Use crimping tool J35910 to obtain
satisfactory crimp. An easy method of checking the clamp gap is to attempt to slip a common size 53 drill bit through the damp against the hose. If the bit
does not slide through, the clamp is tight enough, (the bit is .0595 inches in diameter). If the bit slides easily through the gap, the damp is not tight
