Chevrolet Silverado / GMC Sierra. Service manual — part 2704

DIAGNOSTIC STARTING POINT - POWER STEERING SYSTEM (W/O ELECTRO-HYDRA
HYDRAULIC STEERING)

Begin the system diagnosis by reviewing the system Description and Operation. Refer to Power
Steering System Description and Operation. Reviewing the Description and Operation
information will help you determine the correct symptom diagnostic procedure when a
malfunction exists. Reviewing the Description and Operation information will also help you
determine if the condition described by the customer is normal operation. Refer to Symptoms -
Power Steering System in order to identify the correct procedure for diagnosing the system and
where the procedure is located.

SYMPTOMS - POWER STEERING SYSTEM

Visual/Physical Inspection

Inspect for aftermarket devices which could affect the operation of the power steering
system.

Inspect the easily accessible or visible system components for obvious damage or conditions
which could cause the symptom.

Inspect for leaking power steering components. If necessary, refer to Power Steering Fluid
Leaks.

Verify the power steering reservoir for the proper operating specification. Refer to
Checking and Adding Power Steering Fluid (With Hydroboost) or Checking and
Adding Power Steering Fluid (Without Hydroboost).

Inspect the power steering fluid for the following indications of contamination:

Milky fluid - water

Brown fluid - burnt

Debris in fluid - plastic or dirt

If necessary, flush the power steering system. Refer to Power Steering System Flushing.

Symptoms List

Refer to a symptom diagnostic procedure from the following list in order to diagnose the
symptom:

IMPORTANT: Review the system description and operation in order to

familiarize yourself with the system functions. Refer to Power
Steering System Description and Operation.

2008 Chevrolet Silverado 1500

2008 STEERING Power Steering - Cab & Chassis Sierra, Cab & Chassis Silverado, Sierra & Silverado

Power Steering Fluid Leaks

Rattle, Clunk, or Shudder Noise from the Power Steering System

Whine or Growl Noise from the Power Steering System (Without Hydraulic Booster)
or Whine or Growl Noise from the Power Steering System (With Hydraulic Booster)

Poor Return of Steering Wheel

Steering Effort Hard in One or Both Directions

Steering Effort Too Easy in One or Both Directions

POWER STEERING SYSTEM TEST

Fig. 4: Testing Rack and Pinion System Pressures
Courtesy of GENERAL MOTORS CORP.

Callout

Component Name

2008 Chevrolet Silverado 1500

2008 STEERING Power Steering - Cab & Chassis Sierra, Cab & Chassis Silverado, Sierra & Silverado

Fig. 5: Testing Recirculating Ball System Pressures
Courtesy of GENERAL MOTORS CORP.

1

Power Steering Return Hose

2

Power Steering Pressure Hose

Callout

Component Name

1

Power Steering Return Hose

2

Power Steering Pressure Hose

2008 Chevrolet Silverado 1500

2008 STEERING Power Steering - Cab & Chassis Sierra, Cab & Chassis Silverado, Sierra & Silverado

Test Description

The numbers below refer to the step numbers on the diagnostic table.

5: This step tests the system for restrictions.

7: This step tests the following components for the following conditions:

The pump for internal leaks

The power steering pipes and hoses for kinks

8: This step tests the ability of the pump to regulate flow at maximum pressure.

10: This step tests the ability of the pump to regulate flow under normal operating
conditions.

12: This step tests the internal components of the pump and the gear.

IMPORTANT: Power steering hoses may not look kinked, but have a

layer separation causing the inner hose to collapse and
restrict power steering fluid flow.

Step

Action

Value(s)

Yes

No

DEFINITION: The Power Steering System Test Procedure will perform the following
functions:

Test the operation of the hydraulic power steering system.

Test the operation of the power steering pump and power steering gear.

Identify restrictions in the system.

1

Inspect the power steering fluid for the
following indications of contamination:

Milky fluid - water

Brown fluid - burnt

Debris in fluid - plastic or dirt

Is the fluid free of contamination?

-

Go to Step 3 Go to Step 2

2

Flush the power steering system. Refer to
Power Steering System Flushing.
Did you complete the procedure?

-

Go to Step 3

-

IMPORTANT:

2008 Chevrolet Silverado 1500

2008 STEERING Power Steering - Cab & Chassis Sierra, Cab & Chassis Silverado, Sierra & Silverado