Chevrolet Silverado / GMC Sierra. Service manual — part 2743

4. Clean any excess fluid from the vehicle and remove the drain pans.

5. Fill and bleed the power steering system. Refer to Power Steering System Bleeding.

DESCRIPTION AND OPERATION

POWER STEERING SYSTEM DESCRIPTION AND OPERATION

The hydraulic power steering pump is a constant displacement vane-type pump that provides
hydraulic pressure and flow for the power steering gear. The hydraulic power steering pump is
belt-driven.

The power steering fluid reservoir holds the power steering fluid and may be integral with the
power steering pump or remotely located. The following locations are typical locations for the
remote reservoir:

Mounted to the front of the dash panel

Mounted to the inner fender

Mounted to a bracket on the engine

The 2 basic types of power steering gears are listed below:

A recirculating ball system

A rack and pinion system

In the recirculating ball system, a worm gear converts steering wheel movement to movement of a
sector shaft. A pitman arm attached to the bottom of the sector shaft actually moves one tie rod
and an intermediate rod move the other tie rod.

In the rack and pinion system, the rack and the pinion are the 2 components that convert steering
wheel rotation to lateral movement. The steering shaft is attached to the pinion in the steering
gear. The pinion rotates with the steering wheel. Gear teeth on the pinion mesh with the gear
teeth on the rack. The rotating pinion moves the rack from side to side. The lateral action of the
rack pushes and pulls the tie rods in order to change the direction of the vehicle's front wheels.

The power steering pressure hose connects the power steering pump union fitting to the power
steering gear and allows pressurized power steering fluid to flow from the pump to the gear.

The power steering return hose returns fluid from the power steering gear back to the power
steering fluid reservoir. The power steering return line may contain an integral fin-type or line-
type power steering fluid cooler.

2008 Chevrolet Silverado 1500

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

In a typical power steering system, a pump generates hydraulic pressure, causing fluid to flow, via
the pressure hose, to the steering gear valve assembly. The steering gear valve assembly regulates
the incoming fluid to the right and left chambers in order to assist in right and left turns.

Turning the steering wheel activates the valve assembly, which applies greater fluid pressure and
flow to 1 side of the steering gear piston, and lower pressure and flow to the other side of the
piston. The pressure assists the movement of the gear piston. Tie rods transfer this force to the
front wheels, which turn the vehicle right or left.

SPECIAL TOOLS AND EQUIPMENT

SPECIAL TOOLS

Illustration

Tool Number/ Description

J 4245

Internal Snap Ring Pliers

J 6219

Pitman Shaft Seal Installer

J 6278

Bearing Remover and Installer

2008 Chevrolet Silverado 1500

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

J 8001

Dial Indicator Set

J 22610

Keystone Clamp Pliers

J 24319-B

Steering Linkage and Tie Rod Puller

J 25033-C

Pulley Installer

2008 Chevrolet Silverado 1500

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

J 25034-C

Pulley Remover

J 39570

Chassis Ear

J 42640

Steering Column Anti-Rotation Pin

J 44586

Power Steering Gear Oil Seal

Remover/Installer

J 44721

Power Steering Analyzer

2008 Chevrolet Silverado 1500

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